Paula's Choice SKIN PERFECTING 2% BHA Liquid Exfoliant vs The Ordinary Glycolic Acid 7% Exfoliating Toner

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 · 83 people · adults with comedones (41 serum+mask, 42 serum alone) · Adults in Shanghai with comedones, PIE and PIH, using the serum for 8 weeks. · 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.

PMID 36999489

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 · Acne vulgaris in people aged nine and older, as covered by the guideline's scope.

PMID 38300170

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 · 46 people · People with mild to moderate acne, mostly aged 12 to 30 · 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. · 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.

PMID 32356369

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 · 42 people · people (37 women, 5 men) with mild-to-moderate acne and oily or combination skin, mean age 25.9 · Sebum, skin hydration, transepidermal water loss and acne grade over 21 days in people with oily or combination skin. · One centre, 21 days, 37 of 42 participants were women, and the research group was affiliated with the product maker.

PMID 40682377

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 · 20 people · patients with acne vulgaris · Patients with acne vulgaris receiving two 50% glycolic acid + 0.5% salicylic acid peels 2 weeks apart (one side vs Jessner's solution on the other). · Small sample (20) and a combination peel (glycolic + salicylic acid); this is a procedural peel.

PMID 29164826

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 · 37 people · participants in a split-face study · Healthy participants using a 10% glycolic acid biphasic serum on one side of the face for 2 weeks. · Short duration (2 weeks) and a single product formulation; the study measured exfoliation and cosmetic parameters.

PMID 41987370

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 · 51 people · healthy volunteers with dry skin (Kligman score 2 or 3) · Corneometry (skin moisture) and transepidermal water loss over 12 hours after one application. · Measured on the forearms. The significant hydration result comes from the full emollient containing both glycerol and petrolatum.

PMID 31532576

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 · Humans in the cited studies, plus animal and in-vitro work on mechanism · Leave-on products. The review discusses both healthy skin and skin with dry or barrier-impaired conditions such as atopic dermatitis. · A narrative review. It compiles mechanisms and results from other studies.

PMID 18510666