PoreWise La Roche-Posay · Serums
Pure Vitamin C12 Serum
Product
- Brand:
- La Roche-Posay
- Product type:
- Serums
- Last checked:
- 2026-10-30
- Formula version:
- Pack label · 2026-10-30 on the brand's Singapore product page (Asian formula)
- Fragrance & alcohol:
- Contains fragrance · Contains alcohol (denatured)
30 ingredients on this list · WATER at number 1 · Vitamin C (L-ascorbic acid) at number 2 · DIMETHICONE at number 3
Product description
A water-based serum built on 12% pure ascorbic acid, buffered with potassium hydroxide; ascorbic acid is the second ingredient on the list. It also carries hyaluronic acid, adenosine and vitamin E, and contains alcohol denat. and fragrance.
Brand's own claims
The brand's own claims, quoted from its own material.
Full ingredient list
Kept exactly as the source printed it, including spelling in the original.
- 1 WATER
- 2 ASCORBIC ACID
- 3 DIMETHICONE
- 4 GLYCERIN
- 5 ALCOHOL DENAT.
- 6 POTASSIUM HYDROXIDE
- 7 POLYSILICONE-11
- 8 SILICA
- 9 PENTAERYTHRITYL TETRAETHYLHEXANOATE
- 10 PEG-20 METHYL GLUCOSE SESQUISTEARATE
- 11 SODIUM HYALURONATE
- 12 ADENOSINE
- 13 POLOXAMER 338
- 14 AMMONIUM POLYACRYLOYLDIMETHYL TAURATE
- 15 HYDROLYZED HYALURONIC ACID
- 16 CAPRYLIC/CAPRIC TRIGLYCERIDE
- 17 CAPRYLYL GLYCOL
- 18 CITRIC ACID
- 19 LAURETH-7
- 20 TRISODIUM ETHYLENEDIAMINE DISUCCINATE
- 21 BIS-PEG/PPG-16/16 PEG/PPG-16/16 DIMETHICONE
- 22 ACETYL DIPEPTIDE-1 CETYL ESTER
- 23 XANTHAN GUM
- 24 PENTYLENE GLYCOL
- 25 POLYACRYLAMIDE
- 26 C13-14 ISOALKANE
- 27 TOCOPHEROL
- 28 PENTAERYTHRITYL TETRA-DI-T-BUTYL HYDROXYHYDROCINNAMATE
- 29 SALICYLIC ACID
- 30 PARFUM
Original label text
AQUA / WATER / EAU ● ASCORBIC ACID ● DIMETHICONE ● GLYCERIN ● ALCOHOL DENAT ● POTASSIUM HYDROXIDE ● POLYSILICONE-11 ● SILICA ● PENTAERYTHRITYL TETRAETHYLHEXANOATE ● PEG-20 METHYL GLUCOSE SESQUISTEARATE ● SODIUM HYALURONATE ● ADENOSINE ● POLOXAMER 338 ● AMMONIUM POLYACRYLOYLDIMETHYL TAURATE ● HYDROLYZED HYALURONIC ACID ● CAPRYLIC/CAPRIC TRIGLYCERIDE ● CAPRYLYL GLYCOL ● CITRIC ACID ● LAURETH-7 ● TRISODIUM ETHYLENEDIAMINE DISUCCINATE ● BIS-PEG/PPG-16/16 PEG/PPG-16/16 DIMETHICONE ● ACETYL DIPEPTIDE-1 CETYL ESTER ● XANTHAN GUM ● PENTYLENE GLYCOL ● POLYACRYLAMIDE ● C13-14 ISOALKANE ● TOCOPHEROL ● PENTAERYTHRITYL TETRA-DI-T-BUTYL HYDROXYHYDROCINNAMATE ● SALICYLIC ACID ● PARFUM / FRAGRANCE
Ingredient analysis
Vitamin C (L-ascorbic acid) · Actives · GLYCERIN · Humectants · DIMETHICONE · Emollients
Humectants
5Bind water and draw it into the upper layers of the skin.
Emollients
3Fill the gaps between corneocytes to soften and smooth the surface.
Preservatives
2Inhibit microbial growth so the product stays safe to use.
Antioxidants
3Slow oxidation of the formula or of skin surface lipids.
Soothing agents
1Used to reduce the sensation of irritation or discomfort.
Chelating agents
2Binds metal ions to keep the formula stable.
Texture agents
6Set the viscosity and feel of a formula.
Solvents
5Dissolve or carry other ingredients.
Emulsifiers
4Keep oil and water mixed in a stable formula.
Evidence
- Skin effect Human trial Certainty: Moderate Primary source
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.
Who it applies to: Pigmentation index, dermoscopic pigmentation and brightness (L*) of solar lentigines over three months, with two months of follow-up.
Study limits: The serum combines two actives. Each person applied the product to one side of the body and the vehicle to the other. 30 people, and six halo-depigmentation events were possibly related to the product. The authors call for larger studies.
- Skin effect Human trial Certainty: Moderate Primary source
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.
Who it applies to: Women aged 30-65 applying the serum to one side of the face for 2 months, with the untreated side as control.
Study limits: Split-face with an untreated.
- Skin effect Human trial Certainty: Moderate Primary source
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.
Who it applies to: Adults aged 36-72 with mild-to-moderate facial photodamage, applying the serum daily for 3 months.
Study limits: Small sample (19) in photodamaged.
- Skin effect Human trial Certainty: Moderate Primary source
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.
Who it applies to: Adults over 60 with Bateman purpura (senile purpura) applying 5% topical vitamin C twice daily for 12 weeks.
Study limits: Small sample (18 patients) and a single-centre study; the population is photodamaged older skin.
- Skin effect Human trial Certainty: Low Primary source
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.
Who it applies to: Instrument-measured brightness, melanin index and skin thickness in mixed-type (pigment plus vascular) dark circles over eight weeks.
Study limits: Three actives were used together. 24 people took part, all with the mixed type of dark circles; a separate 100-person study was used first to choose which measurements to trust. The abstract reports instrument readings.
- Skin effect Human trial Certainty: Low Primary source
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.
Who it applies to: Women aged 43-65 with photoaged facial skin, applying the serum twice daily for 12 weeks.
Study limits: Radiance was a clinical grading parameter.
- Skin effect Review article Certainty: Low Primary source
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.
Who it applies to: Topical vitamin C formulations studied for melasma or photodamage.
Study limits: The included trials were small; the review notes more studies are needed on the ideal concentration and long-term effect.
- Skin effect Human trial Certainty: Moderate Primary source
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).
Who it applies to: Adults in Shanghai with comedones, PIE and PIH, using the serum for 8 weeks.
Study limits: Both groups used active products; improvements were reported against baseline and between the two active groups. Industry-funded. This is the trial found that counted open and closed comedones separately.
- Skin effect Clinical guideline Certainty: Moderate Primary source
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.
Who it applies to: Acne vulgaris in people aged nine and older, as covered by the guideline's scope.
- Skin effect Review article Certainty: Low Primary source
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.
Who it applies to: Topical salicylic acid for mild to moderate acne. Most participants in the review were 12 to 30 years old, and most studies ran longer than eight weeks.
Study limits: The review covers 49 trials with 3880 participants, salicylic acid appears in a small part of them: 41 to 86 participants per comparison. Every salicylic acid comparison was graded low or very low certainty.
- Skin effect Human trial Certainty: Very low Primary source
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).
Who it applies to: Sebum, skin hydration, transepidermal water loss and acne grade over 21 days in people with oily or combination skin.
Study limits: One centre, 21 days, 37 of 42 participants were women, and the research group was affiliated with the product maker.
- Skin effect Brand claim Certainty: High Public database
Salicylic acid is a keratolytic: it loosens the bonds between dead skin cells so they shed.
Who it applies to: Acne and keratolysis, at the concentrations permitted for cosmetic use.
Study limits: Most evidence comes from leave-on acne treatments. A cleanser is on the skin for a minute. · Finding · SALICYLIC ACID
- Irritation Review article Certainty: Very low Primary source
Trials of topical salicylic acid for acne reported application-site reactions such as scaling and redness.
Who it applies to: Topical salicylic acid in acne trials, mainly leave-on use over eight weeks or longer.
Study limits: The review graded the salicylic acid adverse-event comparisons as very low certainty.
- Skin effect Human trial Certainty: Moderate Primary source
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.
Who it applies to: Corneometry (skin moisture) and transepidermal water loss over 12 hours after one application.
Study limits: Measured on the forearms. The significant hydration result comes from the full emollient containing both glycerol and petrolatum.
- Skin effect Review article Certainty: Moderate Primary source
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.
Who it applies to: Leave-on products. The review discusses both healthy skin and skin with dry or barrier-impaired conditions such as atopic dermatitis.
Study limits: A narrative review. It compiles mechanisms and results from other studies.
- Skin effect Official ingredient listing Certainty: High Public database
Glycerin is classified as a humectant in cosmetic ingredient databases: its role in a formula is to hold water.
Who it applies to: Cosmetic formulas generally. · Ingredient database · GLYCERIN
Study limits: Skin effect of to the stratum corneum comes from a separate review of the literature. · Ingredient database · GLYCERIN
- Skin effect Human trial Certainty: Moderate Primary source
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.
Who it applies to: 0.1% hyaluronic acid creams applied twice daily for 60 days to the eye area of women aged 30-60 with periocular wrinkles.
Study limits: Sixty days, and the vehicle sat on the fellow eye. Hydration and elasticity were read by instruments. The volunteers were women aged 30-60 with eye-area wrinkles.
- How deep it gets In vitro study Certainty: Moderate Primary source
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.
Who it applies to: Excised human skin with intact stratum corneum, measured by Raman micro-imaging after topical application.
Study limits: One laboratory's imaging study. Three molecular-weight grades were tested. "remains above" describes intact stratum corneum in this ex vivo setup.
- Skin effect Brand claim Certainty: Moderate Public database
Hyaluronic acid and its salt bind water at the skin surface, giving a plumper look immediately after application.
Who it applies to: Leave-on hydrating products.
Study limits: The effect is largely surface and temporary. In dry air a humectant. · Finding · Sodium hyaluronate · Hydrolyzed hyaluronic acid
- Skin effect Human trial Certainty: Low Primary source
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%.
Who it applies to: A three-step regimen (lotion, serum, cream) built on a low-molecular-weight hyaluronic acid, used for eight weeks on women with a mean age of 45.2.
Study limits: The percentages are within-group changes. 33 participants in one centre, and the material is described as "nano" hyaluronic acid.
- How deep it gets In vitro study Certainty: Low Primary source
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.
Who it applies to: Reconstituted human epidermis incubated with hyaluronic acid of 20, 50, 130, 300, 800 and 1500 kDa.
Study limits: The material tested is a defined ~50 kDa grade.
- Legal limits Official legal text Certainty: High Primary source
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.
Who it applies to: Products sold in the US that make a skin-protectant claim, with dimethicone between 1 and 30 percent.
Study limits: A monograph entry sets what may be sold and what may be claimed. · 1993 · Consumers of over-the-counter skin protectant products in the US.
- Skin effect Human trial Certainty: Low Primary source
In a double-blind trial that split each scar into two halves. Or made worse, the cosmetic appearance.
Who it applies to: Scars after surgical removal of skin cancer, treated twice daily for four weeks with a petrolatum-based ointment.
Study limits: Fifteen people, one centre, published in 1999. Pigmentation, or the job vitamin E does inside a formula, where it slows oxidation of the oils.
- Sensitization Human trial Certainty: Low Primary source
In the same split-scar trial, 33% of the participants developed contact dermatitis to the vitamin E ointment.
Who it applies to: Vitamin E in a petrolatum-based ointment applied to healing surgical wounds, twice daily for four weeks.
Study limits: Small trial (15 people) with a single product.
Related skin concerns
Skin concerns with evidence for ingredients on this list.
Formula history
1 version of this formula on record.