Evidence

In a double-blind trial of 150 people with mild-to-moderate acne, a 14% gluconolactone solution and a 5% benzoyl peroxide lotion each reduced inflamed and non-inflamed lesion counts significantly more than the vehicle lotion, and fewer side-effects were reported with gluconolactone than with benzoyl peroxide.

Human trial · 1992 · Certainty Moderate · Gluconolactone · Acne and breakouts

In a prospective, randomized, evaluator-blind, split-face trial of 20 patients with acne vulgaris, two 50% glycolic acid + 0.5% salicylic acid peels significantly reduced total lesion count (P<0.001) and produced fewer side effects than Jessner's solution.

Human trial · 2018 · Certainty Moderate · Glycolic acid · Acne and breakouts

The 2024 American Academy of Dermatology acne guideline lists topical salicylic acid as a conditional recommendation. Strong recommendations in the same guideline go to benzoyl peroxide, topical retinoids, topical antibiotics and oral doxycycline.

Clinical guideline · 2024 · Certainty Moderate · Salicylic Acid · Acne and breakouts

A 2026 systematic review and meta-analysis pooled seven clinical studies of tea tree oil for acne (445 patients in total). Acne severity was lower with tea tree oil than with the control treatments (pooled odds ratio 0.74, 95% CI 0.63 to 0.88), adverse events were mostly local and mild, and the reviewers judged the overall risk of bias as low.

Review article · 2026 · Certainty Moderate · Tea tree leaf extract · Teenage skin Acne and breakouts

In a randomized, double-blind, placebo-controlled trial of 60 people with mild-to-moderate acne, 5% tea tree oil gel was 3.55 times more effective than placebo in improving total lesion counts and 5.75 times more effective in improving the acne severity index over 45 days.

Human trial · 2007 · Certainty Moderate · Tea tree leaf extract · Acne and breakouts Teenage skin

Against topical tretinoin, salicylic acid showed similar values in overall acne improvement (RR 1.00, 95% CI 0.92 to 1.09; one trial, 46 participants). The review graded the certainty of that finding as low.

Review article · 2020 · Certainty Low · Salicylic Acid · Acne and breakouts

Trials of topical salicylic acid for acne reported application-site reactions such as scaling and redness.

Review article · 2020 · Certainty Very low · Salicylic Acid · Acne and breakouts Sensitive skin

In 72 people with mild-to-moderate acne, a 15% azelaic acid gel reduced post-inflammatory erythema (PAHPI) significantly more than placebo at weeks 8 and 12, and lowered melanin content in post-inflammatory hyperpigmentation lesions at week 12.

Human trial · 2024 · Certainty High · Azelaic acid · Acne marks and scars

In 28 people with acne-induced post-inflammatory hyperpigmentation, both a 5% stabilised cysteamine cream and a 4% hydroquinone/3% ascorbic acid cream significantly reduced PAHPI scores and melanin index over 4 months, with similar values between treatments.

Human trial · 2024 · Certainty Moderate · Acne marks and scars

Topical glycerol improves stratum corneum hydration, barrier function and skin mechanical properties. The review also reports reduced irritation response and faster wound healing, and traces the effect to aquaporin-3 transport and to glycerol's own presence in the skin.

Review article · 2008 · Certainty Moderate · Glycerin · Dryness Barrier damage Dehydrated skin

A facial moisturiser containing niacinamide improved stratum corneum barrier function and skin hydration, measured instrumentally, in people with rosacea over four weeks of twice-daily use.

Human trial · 2005 · Certainty Low · Niacinamide · Rosacea Barrier damage Sensitive skin

After facial non-ablative fractional laser treatment, a panthenol mask lowered the erythema and pigmentation indices on days 3, 7 and 14 against a saline dressing, raised stratum corneum moisture, and reduced transepidermal water loss over the same days. Sebum content was also higher in the mask group on days 7 and 14.

Human trial · 2025 · Certainty Low · Panthenol · Barrier damage

Panthenol is treated as non-allergenic, this review argues that frequent exposure, especially on damaged skin, can produce hypersensitivity to it. The likely route is a delayed (type IV) contact reaction; immediate and mixed reactions remain possible. Proposes patch testing with the patient's own product and with panthenol 5% in petrolatum.

Review article · 2026 · Certainty Low · Panthenol · Sensitive skin Barrier damage

US regulation lists dimethicone as a permitted active ingredient in over-the-counter skin protectant products, at 1 to 30 percent. That is a legal status in one market, and it puts dimethicone in the same list as petrolatum, glycerin and colloidal oatmeal.

Official legal text · 1993 · Certainty High · Dimethicone · Barrier damage

In 83 adults with comedones, a serum containing salicylic acid and lipohydroxy acid significantly improved open comedones on the nose, closed comedones on the face, skin pore density, sebum secretion and skin hydration from baseline after 8 weeks; adding a mask improved closed comedones more than the serum alone (-6.56 vs -5.19, p = 0.022).

Human trial · 2023 · Certainty Moderate · Salicylic Acid · Blackheads Closed comedones Large pores

In 23 women, a single application of a 4% alpha-hydroxy acid solution combined with negative-pressure physical action significantly reduced whitehead and blackhead counts at 1, 2 and 4 weeks, and reduced pore area and number at week 1, compared with AHA peeling alone.

Human trial · 2015 · Certainty Low · Glycolic acid Lactic Acid · Blackheads Closed comedones Large pores

In a 12-week randomized trial of 80 subjects aged 12 and over with mild-to-moderate acne, a botanical anti-inflammatory OTC skincare regimen produced significantly lower closed-comedone counts than a benzoyl peroxide comparator at week 4 (P<0.001) and week 12 (P=0.006), with fewer inflammatory lesions at week 4 (P=0.016).

Human trial · 2015 · Certainty Moderate · Bumps and rough texture Closed comedones Teenage skin

In a randomized, placebo-controlled split-face study of 30 healthy Japanese women, a cosmetic containing 4% niacinamide reduced the skin-surface average roughness (Ra) value significantly more than the niacinamide-free control site after 8 weeks (P<0.05).

Human trial · 2008 · Certainty Moderate · Niacinamide · Bumps and rough texture

In a 2-week double-blind split-face study of 37 participants, a biphasic serum with 10% glycolic acid delivered 45.52% greater exfoliation (p<0.001) and improved skin brightness, texture and hydration versus the comparison side.

Human trial · 2026 · Certainty Moderate · Glycolic acid · Bumps and rough texture

In an 8-week randomized, vehicle-controlled split-face study of 23 people with blemish-prone skin, an anhydrous 0.1% retinal / 10% azelaic acid concentrate improved the pore parameter by 22.3% versus vehicle (p=0.015) and skin texture by 5.6% versus vehicle (p=0.0016), and reduced surface irregularities by 12.7% versus vehicle (p=0.0053).

Human trial · 2026 · Certainty Moderate · Retinal Azelaic acid · Bumps and rough texture Large pores

In a 3-month randomized, double-blind, vehicle-controlled trial of 19 volunteers with photodamaged skin, topical ascorbic acid produced a 73.7% greater improvement in optical profilometry Ra and shadows values than the vehicle, with significant clinical improvement in tactile roughness.

Human trial · 1999 · Certainty Moderate · Vitamin C (L-ascorbic acid) · Bumps and rough texture

In a 12-week randomized trial of 80 subjects aged 12 and over with mild-to-moderate acne, a botanical anti-inflammatory OTC skincare regimen produced significantly lower closed-comedone counts than a benzoyl peroxide comparator at week 4 (P<0.001) and week 12 (P=0.006), with fewer inflammatory lesions at week 4 (P=0.016).

Human trial · 2015 · Certainty Moderate · Bumps and rough texture Closed comedones Teenage skin

In 83 adults with comedones, a serum containing salicylic acid and lipohydroxy acid significantly improved open comedones on the nose, closed comedones on the face, skin pore density, sebum secretion and skin hydration from baseline after 8 weeks; adding a mask improved closed comedones more than the serum alone (-6.56 vs -5.19, p = 0.022).

Human trial · 2023 · Certainty Moderate · Salicylic Acid · Blackheads Closed comedones Large pores

In 23 women, a single application of a 4% alpha-hydroxy acid solution combined with negative-pressure physical action significantly reduced whitehead and blackhead counts at 1, 2 and 4 weeks, and reduced pore area and number at week 1, compared with AHA peeling alone.

Human trial · 2015 · Certainty Low · Glycolic acid Lactic Acid · Blackheads Closed comedones Large pores

In a split-face, blinded, placebo-controlled study of 15 volunteers, a grapeseed-oil nanoemulgel applied for 12 weeks significantly reduced facial sebum production and fine and large pores while significantly increasing skin moisture content and elasticity versus placebo (all p<0.05).

Human trial · 2022 · Certainty Low · Grape seed oil · Combination skin Oily skin

In a randomized study of 55 women with oily skin, sebum, hydration and pH were measured separately on the cheeks and in the T-zone before and after six in-clinic sessions. Microneedling lowered T-zone sebum after all six sessions, mandelic-acid peeling lowered it mainly on the cheeks, and the combined protocol lowered it in both areas.

Human trial · 2026 · Certainty Low · Combination skin

In a 21-day prospective study of 42 people with mild-to-moderate acne and oily or combination skin, a salicylic-acid-containing gel used twice daily was associated with a 23.65% fall in sebum, a 40.5% rise in skin hydration, a 49.26% fall in transepidermal water loss and a 23.81% improvement in acne grade (all P < 0.05 except IGA P < 0.001).

Human trial · 2025 · Certainty Very low · Salicylic Acid · Combination skin

In a randomized, double-blind, placebo-controlled trial, a 20% Artemisia absinthium aqueous-extract eye cream produced a significant between-group difference in Mexameter-measured periorbital melanin after treatment (p=0.01), with a greater melanin reduction than placebo.

Human trial · 2023 · Certainty Low · Dark circles

In 33 women, an eye cream lightened dark circles within 7 days by instrumental measurement and within 28 days by clinical assessment over a 56-day study.

Human trial · 2025 · Certainty Low · Dark circles

In a split-face randomized clinical trial of 58 subjects with visible infraorbital dark circles, 8 weeks of a cosmetic eye treatment reduced the validated 10-point dark-circle grade by 0.74 versus baseline and by 0.59 versus the untreated control (P<0.001).

Human trial · 2021 · Certainty Low · Dark circles

In a randomized, double-blind, placebo-controlled split-face trial, 24 people with mixed-type dark circles used a test product containing 3% vitamin C, 0.1% vitamin A and 0.5% vitamin E for eight weeks. Brightness (L*), melanin index and image-analysis lightness improved significantly on the treated side compared with the placebo side.

Human trial · 2016 · Certainty Low · Vitamin C (L-ascorbic acid) Retinol · Dark circles

In a single-blind trial of 11 women, an eye pad containing 3% caffeine and 1% vitamin K in an emu-oil base was worn under one eye and a water pad under the other for four weeks. Visual and instrument assessment found less wrinkle depth and lighter dark circles on the caffeine side.

Human trial · 2015 · Certainty Very low · Caffeine · Dark circles

In a randomized, placebo-controlled, double-blind trial of 102 women with melasma or solar lentigo, a cream with 2.51% arbutin applied twice daily for 8 weeks lightened discolouration in 75.86% of the melasma group and 56.00% of the solar-lentigo group.

Human trial · 2015 · Certainty Moderate · Arbutin · Melasma Dark spots

In a double-blind, vehicle-controlled trial of 30 people with two or more solar lentigines, a serum with 10% L-ascorbic acid and 2% phytic acid lowered the pigmentation index of the treated lesions over three months while the vehicle-treated lesions stayed stable (P <= 0.003 from month 1 to month 4). Six adverse events, mostly halo depigmentation, were judged possibly related to the product.

Human trial · 2011 · Certainty Moderate · Vitamin C (L-ascorbic acid) Phytic Acid · Dark spots

In 30 people with solar lentigines, a stabilised cysteamine cream reduced colourimetric values by 40% and VAS scores by 40% over 12 weeks, versus 2% for both with the vehicle cream.

Human trial · 2024 · Certainty Moderate · Dark spots Sun damage

In 36 people with solar lentigo lesions on the hands, a dermocosmetic lightening product improved papillary brightness, contrast, luminance and redness significantly more than a moisturising control over 12 months.

Human trial · 2019 · Certainty Moderate · Dark spots

In a randomized, double-blind, four-arm crossover study of 51 healthy volunteers with dry skin, an emollient containing glycerol and petrolatum raised corneometry-measured skin moisture significantly above its vehicle (P < 0.0001) over 12 hours. The authors attributed the hydration gain to the glycerol component and the lower water loss to the petrolatum component.

Human trial · 2020 · Certainty Moderate · Glycerin · Dehydrated skin

In a randomized, double-blind, placebo-controlled study of 26 women selected for low stratum corneum water content, applying a lotion and emulsion containing 0.05% sodium trehalose sulfate to the face for 4 weeks decreased transepidermal water loss and increased stratum corneum water content versus the active-free placebo.

Human trial · 2024 · Certainty Moderate · Dehydrated skin

Topical glycerol improves stratum corneum hydration, barrier function and skin mechanical properties. The review also reports reduced irritation response and faster wound healing, and traces the effect to aquaporin-3 transport and to glycerol's own presence in the skin.

Review article · 2008 · Certainty Moderate · Glycerin · Dryness Barrier damage Dehydrated skin

All five 0.1% hyaluronic acid creams tested, from 50 kDa to 2000 kDa, raised skin hydration and overall elasticity above the vehicle cream applied to the other eye at 60 days.

Human trial · 2011 · Certainty Moderate · Hyaluronic acid Sodium hyaluronate · Dehydrated skin

In a randomized, single-blind controlled trial of 54 Japanese women with dry, sensitive facial skin, 4 weeks of a pseudo-ceramide-containing facial spray improved scaling score, stratum corneum water content, TEWL and corneocyte area, while a commercially available spray.

Human trial · 2025 · Certainty Moderate · Dehydrated skin Peeling and flaking

In a double-blind, randomized, half-face controlled trial of 25 Chinese women with sensitive skin, a moisturizer containing 5% fermented tea seed oil significantly improved facial skin hydration versus a base moisturizer over 4 weeks, alongside reductions in redness and facial wrinkles.

Human trial · 2026 · Certainty Low · Dehydrated skin

In adults with mild-to-moderate xerosis (senile xerosis), a cream containing ceramides 1, 3, 6-II improved stratum corneum hydration, transepidermal water loss and skin pH more than a hydrophilic cream, measured at 24 hours and after 28 days of twice-daily use.

Human trial · 2019 · Certainty Moderate · Ceramide NP Ceramide AP Ceramide EOP · Dryness

Topical glycerol improves stratum corneum hydration, barrier function and skin mechanical properties. The review also reports reduced irritation response and faster wound healing, and traces the effect to aquaporin-3 transport and to glycerol's own presence in the skin.

Review article · 2008 · Certainty Moderate · Glycerin · Dryness Barrier damage Dehydrated skin

In a split-face randomized controlled trial of 50 women, a serum with 20% vitamin C, vitamin E and raspberry leaf cell culture extract significantly improved skin radiance measured by Glossymeter GL200, along with skin colour and elasticity, over 2 months.

Human trial · 2020 · Certainty Moderate · Vitamin C (L-ascorbic acid) Tocopherol · Dull skin

In 31 women aged 43-65, a serum combining vitamins C and E with green tea polyphenols produced statistically significant improvements in all clinically graded parameters over 12 weeks, including enhanced skin smoothness and radiance, plus an ultrasound-measured increase in skin density.

Human trial · 2021 · Certainty Low · Vitamin C (L-ascorbic acid) Tocopherol · Dull skin

In 38 children with atopic dermatitis, a cream containing linoleic acid, 5% dexpanthenol and ceramide improved SCORAD significantly more than a 5% urea cream after 4 weeks (P = 0.043); both groups improved from baseline.

Human trial · 2024 · Certainty Moderate · Panthenol · Eczema and atopic dermatitis

In 44 Japanese people with mild atopic dermatitis, a moisturising gel containing a pseudo-ceramide and eucalyptus extract improved dryness significantly more than the untreated side over 4 weeks, and erythema, itchiness, skin hydration and quality of life improved in the treated group.

Human trial · 2019 · Certainty Low · Eczema and atopic dermatitis

In a 42-subject randomized, multicenter, double-blind, placebo-controlled pilot trial, a cream containing 5% potassium azeloyl diglycinate and 1% hydroxypropyl chitosan applied twice daily for 28 days reduced facial erythema in rosacea, measured both with a Mexameter and by clinical grading, compared with placebo.

Human trial · 2012 · Certainty Low · Facial redness

In a randomized split-face controlled trial in people with rosacea-associated erythema and sensitive skin, a dermocosmetic containing mineralizing water, probiotic fractions, hyaluronic acid and niacinamide significantly improved erythema at day 15 (p<0.01) and day 30 (p<0.001), with skin erythema, tightness, dryness, hydration and TEWL improving versus the untreated side (p<=0.05).

Human trial · 2023 · Certainty Low · Hyaluronic acid Niacinamide · Facial redness

In an open randomized, vehicle-controlled trial of 48 people with mild-to-moderate facial seborrheic dermatitis, 4% nicotinamide cream once daily for 12 weeks reduced the combined erythema/scaling/infiltration score by 75% from baseline versus 35% with the vehicle (p<0.05).

Human trial · 2014 · Certainty Low · Niacinamide · Facial redness

In a 28-day randomized, double-blind split-face trial of 35 people with sensitive skin, a moisturising cream outperformed a control cream in improving pruritus, erythema and transepidermal water loss, while both creams improved sensitive-skin symptoms and signs.

Human trial · 2025 · Certainty Low · Facial redness

In 200 people with facial hyperpigmentation, a 0.2% Thiamidol cream reduced mMASI scores by 36.1% at week 12 versus 16.1% with the vehicle cream (all time points P < 0.001).

Human trial · 2026 · Certainty High · Hyperpigmentation

In 91 women with melasma, a skincare routine containing vitamin B3 (niacinamide) and 2-mercaptonicotinyl glycine significantly reduced MASI after 3 months, with roughly 38-41% reduction by 6 months.

Human trial · 2025 · Certainty Moderate · Niacinamide · Hyperpigmentation

In 83 adults with comedones, a serum containing salicylic acid and lipohydroxy acid significantly improved open comedones on the nose, closed comedones on the face, skin pore density, sebum secretion and skin hydration from baseline after 8 weeks; adding a mask improved closed comedones more than the serum alone (-6.56 vs -5.19, p = 0.022).

Human trial · 2023 · Certainty Moderate · Salicylic Acid · Blackheads Closed comedones Large pores

In a 4-week randomized, double-blind controlled trial of 34 men with mild-to-moderate acne, a cleanser formulated with tris(hydroxymethyl)aminomethane and L-arginine significantly reduced the average pore size with keratotic plugs on the cheeks, along with non-inflammatory and inflammatory acne lesions.

Human trial · 2020 · Certainty Moderate · Large pores

In a randomized, double-blind, placebo-controlled split-face trial of 52 Taiwanese subjects, 4% niacinamide alone significantly reduced instrument-measured pore counts at week 8, and 4% niacinamide with 0.03% kinetin produced persistent significant reductions in pore, spot, wrinkle and evenness counts at weeks 8 and 12.

Human trial · 2007 · Certainty Moderate · Niacinamide · Large pores

In an 8-week randomized, vehicle-controlled split-face study of 23 people with blemish-prone skin, an anhydrous 0.1% retinal / 10% azelaic acid concentrate improved the pore parameter by 22.3% versus vehicle (p=0.015) and skin texture by 5.6% versus vehicle (p=0.0016), and reduced surface irregularities by 12.7% versus vehicle (p=0.0053).

Human trial · 2026 · Certainty Moderate · Retinal Azelaic acid · Bumps and rough texture Large pores

In 23 women, a single application of a 4% alpha-hydroxy acid solution combined with negative-pressure physical action significantly reduced whitehead and blackhead counts at 1, 2 and 4 weeks, and reduced pore area and number at week 1, compared with AHA peeling alone.

Human trial · 2015 · Certainty Low · Glycolic acid Lactic Acid · Blackheads Closed comedones Large pores

In 72 women with visible signs of ageing, a niacinamide-containing biomimetic lamellar cream significantly improved the Cutometer R5 elasticity parameter, wrinkle score, TEWL and corneometer values over 4 weeks compared against the untreated side.

Human trial · 2019 · Certainty Moderate · Niacinamide · Loss of firmness

In 60 healthy women aged 40-50, a topical peptide formulation significantly increased stratum corneum water content and skin elasticity after 28 days, and affected dermis echogenicity after 90 days.

Human trial · 2019 · Certainty Low · Loss of firmness

In a randomized, placebo-controlled, double-blind trial of 102 women with melasma or solar lentigo, a cream with 2.51% arbutin applied twice daily for 8 weeks lightened discolouration in 75.86% of the melasma group and 56.00% of the solar-lentigo group.

Human trial · 2015 · Certainty Moderate · Arbutin · Melasma Dark spots

In a randomized, double-blind, controlled study of 90 volunteers with melasma, the arbutin-cream arm showed a significant fall in melasma severity score from 12.65 to 10.84 over 12 weeks; two participants had mild erythema and itching that resolved after stopping the cream.

Human trial · 2019 · Certainty Moderate · Arbutin · Melasma

A 2026 review of the 2015-2025 literature concluded that sun protection plays a central role in the prevention and treatment of pigmentation disorders including melasma and post-inflammatory hyperpigmentation, and that broad-spectrum sunscreens with visible-light protection may enhance protection against hyperpigmentation.

Review article · 2026 · Certainty Moderate · Avobenzone Homosalate Octisalate Octocrylene Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate · Sun protection Melasma

In a randomized trial of 50 female melasma patients, a topical 5% tranexamic acid cream applied twice daily for 12 weeks reduced the Melasma Area and Severity Index by 50.88% (p=0.001).

Human trial · 2025 · Certainty Moderate · Tranexamic acid · Melasma

A 2023 systematic review of 7 randomized controlled trials (139 volunteers) found that topically applied vitamin C made uneven, wrinkled skin appear smoother and lightened pigmentation on objective assessments, though noticeable change may need long-term use.

Review article · 2023 · Certainty Low · Vitamin C (L-ascorbic acid) · Wrinkles and fine lines Melasma

In 90 people with seborrhea, moisturisers containing 2% L-carnitine, 5% epigallocatechin gallate, or both produced statistically significant reductions in sebum level from baseline over 4 weeks, with the EGCG and combination groups showing greater anti-sebum effects than L-carnitine alone (p = 0.009).

Human trial · 2023 · Certainty Moderate · Oily skin

In a double-blind, placebo-controlled trial of 100 Japanese subjects, a 2% niacinamide moisturiser significantly lowered sebum excretion rate after 2 and 4 weeks; in a separate 30-person Caucasian split-face study it significantly reduced casual sebum level after 6 weeks.

Human trial · 2006 · Certainty Moderate · Niacinamide · Oily skin

In a split-face, blinded, placebo-controlled study of 15 volunteers, a grapeseed-oil nanoemulgel applied for 12 weeks significantly reduced facial sebum production and fine and large pores while significantly increasing skin moisture content and elasticity versus placebo (all p<0.05).

Human trial · 2022 · Certainty Low · Grape seed oil · Combination skin Oily skin

In a 12-week single-blind, base-controlled study in healthy men, a cream containing 3% Cannabis seed extract significantly reduced cheek sebum and erythema compared with the extract-free base (p<0.05).

Human trial · 2015 · Certainty Low · Skincare for men Oily skin

In a double-blind randomized controlled trial of acne patients all using adapalene 0.3%/benzoyl peroxide 2.5% gel, adding a ceramide-containing cleanser and facial lotion for 12 weeks yielded significantly lower inflammatory lesion counts than a basic face-wash control, with significantly better TEWL and lower investigator scores for dryness, erythema and scaling.

Human trial · 2023 · Certainty Moderate · Skincare while on acne medication Peeling and flaking

In a half-face randomized controlled study of 64 women, a moisturizing facial cream applied after medical-mask wear improved the treated half-face's skin dryness score by -1.00 and TEWL by -2.95 g/h per cm2 within 10 minutes, versus 0.00 and -0.68 on the untreated half-face (both p<0.001); a cream-plus-mask combination gave larger improvements at 1 hour and later.

Human trial · 2024 · Certainty Moderate · Peeling and flaking

In a double-blind comparative study of 70 women with mild-to-moderate facial dryness, a multi-weight hyaluronic acid plus antioxidant lotion produced significantly greater improvements in clinician-graded visible dryness, roughness and fine lines over 8 weeks than a single-weight hyaluronic acid plus ceramide lotion, with improvements visible from week 2.

Human trial · 2024 · Certainty Moderate · Hyaluronic acid · Peeling and flaking

In a randomized, single-blind controlled trial of 54 Japanese women with dry, sensitive facial skin, 4 weeks of a pseudo-ceramide-containing facial spray improved scaling score, stratum corneum water content, TEWL and corneocyte area, while a commercially available spray.

Human trial · 2025 · Certainty Moderate · Dehydrated skin Peeling and flaking

In a randomized, investigator-blind, split-face trial of 40 Asian acne patients, a moisturizer containing 4-t-butylcyclohexanol, licochalcone A, ceramide and panthenol improved facial hydration more than a traditional moisturizer (p=0.001) and produced lower dryness scores (p=0.021) over 4 weeks.

Human trial · 2026 · Certainty Low · Panthenol · Peeling and flaking

In a randomized, evaluator-blinded study of 32 women, adding a facial hydrating serum to a moisturizer for 2 weeks produced statistically significant improvements in investigator-graded facial dryness and skin softness compared with using the moisturizer alone (P<0.02).

Human trial · 2011 · Certainty Low · Peeling and flaking

In an 8-week open study of 51 people with perioral dermatitis, twice-daily use of a drug-free soothing cosmetic fluid was associated with significant within-group improvement in perioral dermatitis severity (PODSI) and in itching, skin tightness and appearance over time; the improvement was better.

Human trial · 2014 · Certainty Very low · Perioral dermatitis

In 48 people with perioral dermatitis, a skin care cream containing the TRPV1 inhibitor 4-t-butylcyclohexanol significantly reduced perioral dermatitis severity scores, subjective numerical ratings, transepidermal water loss, erythema and improved quality of life over 8 weeks.

Human trial · 2020 · Certainty Very low · Perioral dermatitis

In 24 people with mild-to-moderate plaque psoriasis, a vitamin B12-containing ointment reduced PASI by 87.6% from baseline at week 12 versus 23.1% with a standard glycerol-petrolatum emollient on the opposite side (p < 0.001).

Human trial · 2017 · Certainty Low · Psoriasis

In a randomized, double-blind trial of 60 people with localised psoriasis, a 0.25% zinc pyrithione cream reduced mean PASI from 3.4 to 0.9 over 3 months (p < 0.01) and was significantly better than the emollient base, which changed from 4.3 to 3.9 (p > 0.05).

Human trial · 2011 · Certainty Low · Psoriasis

In moderate-to-severe papulopustular rosacea, once-daily ivermectin 1% cream reduced inflammatory lesion counts by 83.0% from baseline at 16 weeks versus 73.7% for twice-daily metronidazole 0.75% cream (P<0.001, 962 participants), and more subjects reached 'clear' or 'almost clear' on the investigator's global assessment (84.9% vs 75.4%, P<0.001).

Human trial · 2015 · Certainty High · Rosacea

In a randomized controlled trial of 75 patients with erythematotelangiectatic rosacea, a moisturizer containing Centella asiatica extract, ceramide NP and panthenol produced greater improvements in facial redness and barrier measures than the control group at day 28.

Human trial · 2026 · Certainty Moderate · Centella asiatica · Rosacea

Low-dose (anti-inflammatory, sub-antimicrobial) oral doxycycline 40 mg once daily was significantly more effective than placebo at reducing inflammatory lesions in rosacea across two pivotal randomized, double-blind, placebo-controlled, multicenter trials (16 weeks). The 40 mg dose works as an anti-inflammatory.

Review article · 2010 · Certainty Moderate · Rosacea

A facial moisturiser containing niacinamide improved stratum corneum barrier function and skin hydration, measured instrumentally, in people with rosacea over four weeks of twice-daily use.

Human trial · 2005 · Certainty Low · Niacinamide · Rosacea Barrier damage Sensitive skin

In a double-blind, placebo-controlled randomized cross-over study in people with mild acne, one month of topical linoleic acid reduced the overall size of follicular casts and microcomedones by almost 25% on digital image analysis of cyanoacrylate follicular biopsies.

Human trial · 1998 · Certainty Moderate · Linoleic Acid · Sebaceous filaments

In 88 women with sensitive skin, a face cream containing Centella asiatica leaf extract, ceramide NP and panthenol lowered the SS-10 symptom score by 66% at week 2 and 76% at week 4, with irritation, tautness, itching and redness all significantly reduced.

Human trial · 2025 · Certainty Moderate · Centella asiatica Ceramide NP Panthenol · Sensitive skin

In a randomized, double-blind, vehicle-controlled split-body trial of 50 people with sensitive skin, an emollient containing Ceramide NP C15 significantly reduced transepidermal water loss in participants with an impaired skin barrier over 6 weeks.

Human trial · 2026 · Certainty Moderate · Ceramide NP · Sensitive skin

In 110 people with facial sensitive skin, a cream containing panthenol used twice daily for 28 days significantly increased stratum corneum moisture and reduced erythema index, redness (a* value) and transepidermal water loss.

Human trial · 2024 · Certainty Moderate · Panthenol · Sensitive skin

A facial moisturiser containing niacinamide improved stratum corneum barrier function and skin hydration, measured instrumentally, in people with rosacea over four weeks of twice-daily use.

Human trial · 2005 · Certainty Low · Niacinamide · Rosacea Barrier damage Sensitive skin

Panthenol is treated as non-allergenic, this review argues that frequent exposure, especially on damaged skin, can produce hypersensitivity to it. The likely route is a delayed (type IV) contact reaction; immediate and mixed reactions remain possible. Proposes patch testing with the patient's own product and with panthenol 5% in petrolatum.

Review article · 2026 · Certainty Low · Panthenol · Sensitive skin Barrier damage

The CIR expert panel's 1985 assessment of stearyl alcohol reports minimal to mild cutaneous irritation in rabbit tests, and a very low order of irritation and sensitization in clinical patch testing. It concluded that stearyl alcohol is safe as used in cosmetics.

Review article · 1985 · Certainty Low · Cetearyl Alcohol · Sensitive skin

Trials of topical salicylic acid for acne reported application-site reactions such as scaling and redness.

Review article · 2020 · Certainty Very low · Salicylic Acid · Acne and breakouts Sensitive skin

The EU Scientific Committee on Consumer Safety concluded in 2016 that 2-phenoxyethanol is safe as a preservative at a maximum of 1.0%, which is the limit already set in Annex V/29 of the EU Cosmetics Regulation. It estimated a margin of safety of about 50 for children.

Official legal text · 2016 · Certainty High · Phenoxyethanol · Sensitive skin

In a double-blind randomized trial of 180 pregnant women with melasma in their second trimester or later, 5 weeks of liposome-encapsulated Aloe vera leaf gel extract improved MASI scores by 32% versus 10% with the non-liposomal Aloe vera gel control, with a significant between-group difference in mean MASI after treatment.

Human trial · 2017 · Certainty Moderate · Aloe Barbadensis Leaf Extract · Skincare during pregnancy

In a placebo-controlled trial in pregnant women, daily application of a broad-spectrum SPF 10 sunscreen to the face from the second trimester through summer significantly reduced the appearance of melasma compared with placebo among the 30 women with good adherence (14 sunscreen, 16 placebo).

Human trial · 1987 · Certainty Moderate · Skincare during pregnancy

In 20 people with Fitzpatrick skin types IV-V, a broad-spectrum sunscreen containing sclareolide and niacinamide significantly prevented experimentally induced post-inflammatory hyperpigmentation: in stripped, exposed zones the protected skin improved by +5.96 ITA degrees versus -9.88 in unprotected skin (net protection about 16 ITA degrees, p < 0.001).

Human trial · 2026 · Certainty Moderate · Niacinamide · Skincare for deeper skin tones

In 216 Indian adults with Fitzpatrick skin types IV-V and pigmentation irregularities, regular use of two commercial sunscreens over 12 weeks significantly improved the clinical density of pigmented spots, skin radiance and chromameter-measured pigmentation.

Human trial · 2019 · Certainty Low · Skincare for deeper skin tones

In a 12-week randomized, double-blind, placebo-controlled trial of 80 men aged 45-65, a product combining genistein, bakuchiol and vitamins significantly improved cheek skin lightening, colour consistency, forehead spots and skin roughness versus placebo; most other measured parameters showed similar between-group difference.

Human trial · 2026 · Certainty Low · Genistein · Skincare for men

In a placebo-controlled split-face study of 33 healthy Asian men, a once-daily emulsion combining green tea and lotus extracts produced significant improvements in skin roughness, scaliness, smoothness and wrinkling over 60 days, including about 49.99% better smoothness and 23.22% less facial wrinkling from baseline.

Human trial · 2013 · Certainty Low · Skincare for men

In a 12-week single-blind, base-controlled study in healthy men, a cream containing 3% Cannabis seed extract significantly reduced cheek sebum and erythema compared with the extract-free base (p<0.05).

Human trial · 2015 · Certainty Low · Skincare for men Oily skin

In a 12-week base-controlled study of 11 healthy men, a cream containing 4% Tamarindus indica seed extract significantly improved skin elasticity, moisture and Visioscan scaliness, wrinkle, smoothness and roughness parameters (p<=0.05), while the same emulsion the base emulsion showed similar change (p>0.05).

Human trial · 2017 · Certainty Low · Skincare for men

In a double-blind randomized controlled trial of acne patients all using adapalene 0.3%/benzoyl peroxide 2.5% gel, adding a ceramide-containing cleanser and facial lotion for 12 weeks yielded significantly lower inflammatory lesion counts than a basic face-wash control, with significantly better TEWL and lower investigator scores for dryness, erythema and scaling.

Human trial · 2023 · Certainty Moderate · Skincare while on acne medication Peeling and flaking

In 40 people with mild-to-moderate acne all using topical benzoyl peroxide plus adapalene, a moisturiser with ceramides and niacinamide significantly improved non-inflammatory, inflammatory and total acne lesions on that side of the face versus a hydrophilic cream after 8 weeks, and decreased cutaneous irritation.

Human trial · 2024 · Certainty Moderate · Niacinamide Ceramide NP · Skincare while on acne medication

Across six vehicle-controlled studies pooled together (237 on retinol, 234 on vehicle), 0.1% stabilised retinol produced greater improvements from baseline in all signs of photoaging than the vehicle from week 4 through week 12.

Human trial · 2024 · Certainty High · Retinol · Sun damage

In 30 people with solar lentigines, a stabilised cysteamine cream reduced colourimetric values by 40% and VAS scores by 40% over 12 weeks, versus 2% for both with the vehicle cream.

Human trial · 2024 · Certainty Moderate · Dark spots Sun damage

In a 12-week randomized, double-blind trial of 44 people, both 0.5% bakuchiol and 0.5% retinol significantly reduced wrinkle surface area and hyperpigmentation; bakuchiol caused less scaling and stinging.

Human trial · 2019 · Certainty Moderate · Retinol · Sun damage

In a randomized controlled community trial of 903 adults under 55, daily use of a broad-spectrum SPF 15+ sunscreen slowed skin aging over 4.5 years: the daily-sunscreen group showed 24% less photoaging than the discretionary-use group (relative odds 0.76, 95% CI 0.59 to 0.98). The trial measured the act of using a broad-spectrum sunscreen.

Human trial · 2013 · Certainty High · Avobenzone Homosalate Octisalate Octocrylene · Sun protection

A 2026 review of the 2015-2025 literature concluded that sun protection plays a central role in the prevention and treatment of pigmentation disorders including melasma and post-inflammatory hyperpigmentation, and that broad-spectrum sunscreens with visible-light protection may enhance protection against hyperpigmentation.

Review article · 2026 · Certainty Moderate · Avobenzone Homosalate Octisalate Octocrylene Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate · Sun protection Melasma

In a 12-week randomized trial of 80 subjects aged 12 and over with mild-to-moderate acne, a botanical anti-inflammatory OTC skincare regimen produced significantly lower closed-comedone counts than a benzoyl peroxide comparator at week 4 (P<0.001) and week 12 (P=0.006), with fewer inflammatory lesions at week 4 (P=0.016).

Human trial · 2015 · Certainty Moderate · Bumps and rough texture Closed comedones Teenage skin

A 2026 systematic review and meta-analysis pooled seven clinical studies of tea tree oil for acne (445 patients in total). Acne severity was lower with tea tree oil than with the control treatments (pooled odds ratio 0.74, 95% CI 0.63 to 0.88), adverse events were mostly local and mild, and the reviewers judged the overall risk of bias as low.

Review article · 2026 · Certainty Moderate · Tea tree leaf extract · Teenage skin Acne and breakouts

In a randomized, double-blind, placebo-controlled trial of 60 people with mild-to-moderate acne, 5% tea tree oil gel was 3.55 times more effective than placebo in improving total lesion counts and 5.75 times more effective in improving the acne severity index over 45 days.

Human trial · 2007 · Certainty Moderate · Tea tree leaf extract · Acne and breakouts Teenage skin

In a 12-week randomized, double-blind half-face study, a combination of 4-hexylresorcinol and niacinamide improved hyperpigmentation spots (L*), the appearance of fine lines and wrinkles, and skin firmness significantly more than niacinamide alone.

Human trial · 2022 · Certainty Moderate · Niacinamide · Uneven skin tone

In 30 women with melasma or post-inflammatory hyperpigmentation, a serum combining lotus sprout extract, tranexamic acid and niacinamide reduced skin tone unevenness by 38% and 33% respectively over 16 weeks (P < 0.008).

Human trial · 2026 · Certainty Low · Niacinamide Tranexamic acid · Uneven skin tone

Periocular wrinkle depth improved against vehicle with the 50 kDa and 130 kDa hyaluronic acid creams; after 60 days the 300, 800 and 2000 kDa creams matched vehicle on measured roughness.

Human trial · 2011 · Certainty Moderate · Hyaluronic acid · Wrinkles and fine lines

A 0.4% retinol lotion applied to the arm up to three times a week for 24 weeks reduced fine wrinkling significantly more than its vehicle in elderly subjects: score change −1.64 (95% CI −2.06 to −1.22) against −0.08 (−0.17 to 0.01) on a 0–9 severity scale.

Human trial · 2007 · Certainty Moderate · Retinol · Wrinkles and fine lines

In a split-face comparison, 0.075% retinol cream used once nightly for 26 weeks improved fine wrinkling in 27 of 54 participants (50%) against 13 (24%) on the vehicle side, and deep wrinkling in 15 (28%) against 1 (2%).

Human trial · 2009 · Certainty Moderate · Retinol · Wrinkles and fine lines

In a randomized study of 50 women with melasma, topical 3% tranexamic acid serum plus moisturizer reduced periorbital wrinkle grading significantly more than moisturizer alone at weeks 4, 8 and 12, with the benefit persisting after treatment stopped.

Human trial · 2026 · Certainty Moderate · Tranexamic acid · Wrinkles and fine lines

Eight weeks of a low-molecular-weight "nano" hyaluronic acid lotion, serum and cream reduced measured periorbital wrinkle depth by up to 40% and raised corneometer hydration by up to 96%.

Human trial · 2014 · Certainty Low · Hydrolyzed hyaluronic acid · Wrinkles and fine lines

A 2023 systematic review of 7 randomized controlled trials (139 volunteers) found that topically applied vitamin C made uneven, wrinkled skin appear smoother and lightened pigmentation on objective assessments, though noticeable change may need long-term use.

Review article · 2023 · Certainty Low · Vitamin C (L-ascorbic acid) · Wrinkles and fine lines Melasma

In a double-blind, randomized, vehicle-controlled left-right facial study, a moisturizer containing licochalcone A, 1,2-decanediol, L-carnitine and salicylic acid significantly reduced mean non-inflammatory, inflammatory and total lesion counts versus the vehicle moisturizer at week 12 during the maintenance phase after adapalene/benzoyl peroxide treatment.

Human trial · 2020 · Certainty Moderate

In a randomized, double-blind, bilateral paired trial of 25 people with moderate-to-severe xerosis, 40% urea cream was superior to 12% ammonium lactate lotion at day 14 on skin roughness, fissure reduction, thickness and dryness, with skin desquamation measured instrumentally.

Human trial · 2002 · Certainty Moderate · Urea

In a 12-week hemi-member, randomized, double-blind, comparative study of 18 patients over 60 with Bateman purpura, twice-daily 5% topical vitamin C improved skin symptoms and increased dermal thickness and elasticity on the treated side versus control.

Human trial · 2018 · Certainty Moderate · Vitamin C (L-ascorbic acid)

A 2024 review summarises that Centella asiatica's active compounds (asiaticoside, madecassoside, asiatic acid, madecassic acid) support collagen synthesis, moderate inflammation and provide antioxidant protection, and that clinical studies have explored topical Centella asiatica for wound healing and skin recovery.

Review article · 2024 · Certainty Low · Centella asiatica

Nightly 0.075% retinol caused enough irritation for 3 of 57 participants to withdraw from the study; at 0.04% over 13 weeks irritation was reported as minimal, with less improvement in fine wrinkling.

Human trial · 2009 · Certainty Low · Retinol

In the same split-scar trial, 33% of the participants developed contact dermatitis to the vitamin E ointment.

Human trial · 1999 · Certainty Low · Tocopherol

In a double-blind trial that split each scar into two halves. Or made worse, the cosmetic appearance.

Human trial · 1999 · Certainty Low · Tocopherol

Hyaluronic acid of 20-300 kDa crossed the stratum corneum in excised human skin, while hyaluronic acid of 1000-1400 kDa remained in the stratum corneum.

In vitro study · 2016 · Certainty Moderate · Hyaluronic acid Sodium hyaluronate Hydrolyzed hyaluronic acid

In the rabbit ear-canal assay, the nine materials graded positive were eight esters (isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristyl myristate) and cocoa butter.

Animal study · 2007 · Certainty Low · Cetyl Alcohol Cetearyl Alcohol

In reconstituted human epidermis, hyaluronic acid of about 50 kDa penetrated better than the larger grades and increased expression of genes and proteins involved in tight-junction formation and keratinocyte cohesion; its TNF-α expression stayed close from the 20 kDa grade.

In vitro study · 2011 · Certainty Low · Hydrolyzed hyaluronic acid

Glycerin is classified as a humectant in cosmetic ingredient databases: its role in a formula is to hold water.

Official ingredient listing · Certainty High · Glycerin

Retinol, retinyl acetate and retinyl palmitate are restricted under Annex III entry 376 of the EU Cosmetics Regulation: at most 0.05% retinol equivalent in body lotion and 0.3% in other leave-on and rinse-off products, with a mandatory label warning.

Official legal text · 2024 · Certainty High · Retinol

UV filters are permitted up to the maximum concentrations set by each market's regulation.

Official ingredient listing · Certainty High · Avobenzone Homosalate Octisalate Octocrylene

Parabens are preservatives whose permitted concentration is capped by regulation; contact allergy is documented but uncommon.

Official ingredient listing · Certainty Moderate · Methylparaben Propylparaben

Cleansing surfactants remove surface oil along with dirt, which can leave skin feeling tight or dry.

Official ingredient listing · Certainty Moderate · Sodium Lauroyl Sarcosinate Cocamidopropyl Hydroxysultaine Sodium Methyl Cocoyl Taurate

Ceramides, cholesterol and fatty acids are the lipids that make up the skin barrier; formulations add them to replenish it.

Brand claim · Certainty High · Ceramide NP Ceramide AP Ceramide EOP Cholesterol Phytosphingosine

Salicylic acid is a keratolytic: it loosens the bonds between dead skin cells so they shed.

Brand claim · Certainty High · Salicylic Acid

Hyaluronic acid and its salt bind water at the skin surface, giving a plumper look immediately after application.

Brand claim · Certainty Moderate · Sodium hyaluronate Hydrolyzed hyaluronic acid