Clinical Research Tracker

80% Lactic Acid Peel Versus 50% Glycolic Acid Peel for Melasma: A Randomised Clinical Trial

Indian J Dermatol

RCT found 50% glycolic acid peels more effective than 80% lactic acid peels for melasma (median MASI score decrease 2.85 vs 1.8, P=0.009). Glycolic acid superior despite lower concentration used.

Efficacy, safety, and cost-effectiveness of glycolic acid vs. azelaic acid in melasma

J Family Med Prim Care

RCT comparing 12% glycolic acid to 20% azelaic acid in 80 melasma patients. No significant difference in effectiveness, but glycolic acid was more cost-effective.

Comparative efficacy of topical interventions for facial photoaging: a network meta-analysis

Sci Rep

Network meta-analysis of 23 RCTs (3905 participants). Found glycolic acid effective for reducing skin roughness but did NOT achieve statistical significance for fine wrinkle reduction. Retinoids (tretinoin, retinol, isotretinoin) were superior for wrinkles.

Evaluating the Efficacy and Safety of Alpha-Hydroxy Acids in Dermatological Practice: A Comprehensive Clinical and Legal Review

Almeman AA.

Clin Cosmet Investig Dermatol

Comprehensive clinical and legal review evaluating efficacy and safety of AHAs in dermatological practice.

Effect of 5% glycolic acid complex and 20% glycolic acid on mild-to-moderate facial acne vulgaris

Edraki K, et al.

Chin Med J (Engl)

Counter-intuitive finding: 5% glycolic acid complex outperformed 20% glycolic acid across total lesion count, inflammatory lesion count, skin hydration, and patient satisfaction. Demonstrates that formulation quality and free acid value matter more than nominal concentration.

Clinical outcomes and 5-year follow-up results of keratosis pilaris treated by a high concentration of glycolic acid

Liu J, et al.

World J Clin Cases

Rare long-term (5-year) follow-up study. Showed that glycolic acid benefits for keratosis pilaris did not persist after discontinuation. Important for understanding that continuous use is needed for maintained results.

Glycolic acid adjusted to pH 4 stimulates collagen production and epidermal renewal without affecting levels of proinflammatory TNF-alpha in human skin explants

Narda M, Trullas C, Brown A, et al.

J Cosmet Dermatol

Demonstrated that glycolic acid at pH 4 still stimulates collagen production and desquamation without increasing pro-inflammatory TNF-alpha marker. Clinically relevant for showing partially neutralized formulations retain skin-rejuvenating properties.

Safety review of skin care products for acne-prone skin

Dreno B, Bissonnette R, Gagne-Henley A, et al.

Clin Cosmet Investig Dermatol

Confirmed salicylic acid as a well-established ingredient in acne-prone skincare with a favorable safety profile. Reviewed safety data for common acne treatment ingredients.

Two is better than one: the combined effects of glycolic acid and salicylic acid on acne-related disorders

Decker A, Graber EM.

J Cosmet Dermatol

Prospective study finding over 90% of patients reported significant improvement in acne with combined glycolic acid and salicylic acid treatment.

pH-Dependent Antibacterial Activity of Glycolic Acid: Implications for Anti-Acne Formulations

Yang AJ, et al.

Sci Rep

Discovered that glycolic acid has direct pH-dependent antibacterial activity against Cutibacterium acnes. Non-ionized (free acid) form was more bactericidal. Kills C. acnes by disrupting bacterial cell membranes. Effective at concentrations as low as 0.2%.

Dual Effects of Alpha-Hydroxy Acids on the Skin

Tang SC, Yang JH.

Molecules

Comprehensive review of AHA mechanisms. AHAs at low concentrations (<10%) produce corneodesmolysis for exfoliation, while higher concentrations cause epidermolysis. Reviews evidence for both beneficial and adverse effects including photosensitivity, barrier disruption, and anti-inflammatory properties.

Chemical peels for acne vulgaris: a systematic review of randomised controlled trials

Castillo DE, Yousef K.

BMJ Evidence-Based Medicine

Systematic review of 12 RCTs. Glycolic acid peeling was superior to placebo (RR 2.30, 95% CI 1.40-3.77). However, glycolic acid was not significantly more effective than salicylic acid or Jessner solution when compared head-to-head.

Efficacy of microneedling with 70% glycolic acid peel vs microneedling alone in treatment of atrophic acne scars - a randomized controlled trial

Dayal S, et al.

J Cosmet Dermatol

RCT showing microneedling combined with 70% glycolic acid peels outperformed microneedling alone for atrophic acne scars.

A review of the safety of cosmetic procedures during pregnancy and lactation

Trivedi MK, Kroumpouzos G, Murase JE.

Int J Womens Dermatol

Concluded that glycolic acid and lactic acid peels are considered safe at concentrations below 10% during pregnancy. ACOG considers glycolic acid safe during pregnancy based on minimal systemic absorption.

Comparative effects of retinoic acid or glycolic acid vehiculated in different topical formulations

Ramos-e-Silva M, et al.

Clin Cosmet Investig Dermatol

Found retinoic acid enhanced epithelial thickness suggesting intense renewal, while glycolic acid actually reduced thickness. Retinoic acid more effective for cell renewal and exfoliation at basal layer.

Clinical evaluation of glycolic acid chemical peeling in patients with acne vulgaris: a randomized, double-blind, placebo-controlled, split-face comparative study

Kaminaka C, Uede M, Matsunaka H, Furukawa F, Yamamoto Y.

Dermatol Surg

Split-face RCT for moderate acne. 40% glycolic acid at pH 2.0 showed significantly greater improvement than placebo side. Split-face design considered particularly rigorous as each patient serves as own control.

Glycolic acid peel therapy - a current review

Sharad J.

Clin Cosmet Investig Dermatol

Comprehensive review of glycolic acid peel therapy. Confirmed that glycolic acid peels at 20-70% produce consistent improvements in skin texture via controlled exfoliation and epidermal renewal. Reviewed applications for acne, hyperpigmentation, photoaging, and melasma.

Chemical peels for melasma in dark-skinned patients

Sarkar R, Garg S, Bansal S, Sethi S.

J Cutan Aesthet Surg

Reviewed chemical peel use in dark-skinned patients. Concluded glycolic acid is among the safer options when properly administered with lower concentrations, shorter contact times, and gradual escalation.

A 10% glycolic acid containing oil-in-water emulsion improves mild acne: a randomized double-blind placebo-controlled trial

Abels C, Kaszuba A, Michalak I, et al.

J Cosmet Dermatol

Double-blind placebo-controlled RCT. 10% glycolic acid emulsion at pH 4.0 used once daily significantly improved mild acne vs placebo. Improvement significant by day 45. Tolerability not different from placebo. Largest high-quality glycolic acid acne RCT.

Safety of skin care products during pregnancy

Bozzo P, Chua-Gocheco A, Einarson A.

Can Fam Physician

Reviewed safety of topical skincare ingredients during pregnancy. Systemic absorption from typical OTC glycolic acid concentrations (2-10%) is considered minimal. No human studies specifically evaluated topical glycolic acid effects on fetal development.

Glycolic acid induces keratinocyte proliferation in a skin equivalent model via TRPV1 activation

Kim SJ, Won YH.

J Dermatol Sci

Identified TRPV1 (pH-sensitive ion channel) as the molecular mechanism by which glycolic acid stimulates epidermal renewal. Effect was pH-dependent and could be blocked by TRPV1 antagonists. Provides molecular explanation for accelerated cell turnover.

Clinical and cosmeceutical uses of hydroxyacids

Green BA, Yu RJ, Van Scott EJ.

Clin Dermatol

Review by AHA pioneers. Concluded that AHAs at therapeutic concentrations produce measurable improvements in dermal extracellular matrix composition. Also documented PHA properties including antioxidant effects, MMP inhibition, and minimal UV sensitization.

The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin

Kornhauser A, Wei RR, Yamaguchi Y, et al.

J Dermatol Sci

NIH-funded study confirming that 10% glycolic acid increased UV-induced erythema, DNA damage, and sunburn cell formation in human skin. Salicylic acid showed less UV-sensitizing effect. Demonstrates approximately 20% reduction in minimum erythemal dose.

Glycolic acid peels versus salicylic-mandelic acid peels in active acne vulgaris and post-acne scarring and hyperpigmentation: a comparative study

Garg VK, Sinha S, Sarkar R.

Dermatol Surg

Compared glycolic acid peels to salicylic-mandelic acid peels. Found them equally effective for acne and hyperpigmentation, but salicylic-mandelic combination was better tolerated and more suitable for Indian skin types.

Photocarcinogenesis study of glycolic acid and salicylic acid in SKH-1 mice

National Toxicology Program.

NTP Tech Rep

Long-term US government study (36 male + 36 female mice per group). Glycolic acid at 4% and 10% (pH 3.5) with simulated solar light did NOT alter photocarcinogenesis. Despite enhancing acute UV sensitivity, glycolic acid did not increase cancer risk.

Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety

Mukherjee S, Date A, Patravale V, et al.

Clin Interv Aging

Comprehensive retinoid review. Retinol is converted to retinaldehyde then retinoic acid. Retinoic acid binds nuclear receptors (RARs/RXRs) influencing gene expression for collagen production, cell turnover, and sebum regulation.

Natural skin surface pH is on average below 5, which is beneficial for its resident flora

Lambers H, Piessens S, Bloem A, Pronk H, Finkel P.

Int J Cosmet Sci

Characterized natural skin surface pH at approximately 4.5-5.5. Demonstrated that this acidic environment (acid mantle) supports barrier function and resident beneficial flora.

Alpha Hydroxy Acids - Cosmetic Ingredients: Guidance for Industry on Labeling

US Food and Drug Administration.

US FDA

Official FDA guidance noting AHA-containing products increase sun sensitivity. Requires sun protection guidance on all AHA-containing cosmetic product labeling.

Efficacy and safety of 0.1% retinaldehyde/6% glycolic acid (Diacneal) for mild to moderate acne vulgaris

Poli F, Ribet V, Lauze C, Adhoute H, Morinet P.

Dermatol Surg

Multicentre double-blind RCT. Combination of 0.1% retinaldehyde and 6% glycolic acid effective for mild-moderate acne with acceptable tolerability. Provides clinical evidence that AHA and retinoid can work together safely.

Topical glycolic acid enhances photodamage by ultraviolet light

Kaidbey K, Sutherland B, Bennett P, et al.

Photodermatol Photoimmunol Photomed

Randomized double-blind study. After 4 weeks daily 10% glycolic acid at pH 3.5, UV sensitivity increased ~18% (measured by MED decrease) and sunburn cell formation enhanced. Increased photosensitivity reversed within one week of stopping.

Biological effects of glycolic acid on dermal matrix metabolism mediated by dermal fibroblasts and epidermal keratinocytes

Okano Y, Abe Y, Masaki H, et al.

Exp Dermatol

Demonstrated that glycolic acid promotes collagen synthesis through two pathways: directly via fibroblasts, and indirectly through cytokines released by keratinocytes in the epidermis.

The inhibitory effect of glycolic acid and lactic acid on melanin synthesis in melanoma cells

Usuki A, Ohashi A, Sato H, et al.

Exp Dermatol

Demonstrated that glycolic acid directly inhibits tyrosinase activity (enzyme responsible for melanin production) in cell culture. Suggests glycolic acid lightens pigmentation via both accelerated turnover and reduced melanin synthesis.

The combination of glycolic acid peels with a topical regimen in the treatment of melasma in dark-skinned patients: a comparative study

Sarkar R, Kaur C, Bhalla M, Kanwar AJ.

Dermatol Surg

Glycolic acid peels combined with topical hydroquinone and tretinoin produced greater improvement than topical therapy alone in dark-skinned patients with melasma.

Glycolic acid treatment increases type I collagen mRNA and hyaluronic acid content of human skin

Bernstein EF, Lee J, Brown DB, et al.

Dermatol Surg

Landmark study showing that topical application of 20% glycolic acid lotion to forearm skin twice daily for three months significantly increased type I collagen mRNA and hyaluronic acid content compared to vehicle-treated controls. Suggests promotion of dermal remodeling.

Opinion on Alpha-Hydroxy Acids (SCCNFP/0370/00)

Scientific Committee on Consumer Safety (SCCS).

SCCS/SCCNFP

Official EU scientific committee opinion limiting consumer leave-on products to 4% glycolic acid at pH 3.8 or higher. More restrictive than US CIR guidelines.

Increased in vivo collagen synthesis and in vitro cell proliferative effect of glycolic acid

Kim SJ, Park JH, Kim DH, Won YH, Maibach HI.

Dermatol Surg

Confirmed that glycolic acid directly stimulates fibroblast proliferation and collagen production in a dose-dependent manner. Found glycolic acid produced greater collagen synthesis than lactic acid both in vitro and in vivo.

A double-blind randomized clinical trial on the effectiveness of a daily glycolic acid 5% formulation in the treatment of photoaging

Thibault PK, Wlodarczyk J, Wenck A.

Dermatol Surg

Double-blind randomized trial showing daily 5% glycolic acid was effective for treating signs of photoaging.

Final Report on the Safety Assessment of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates

Andersen FA.

Int J Toxicol

Definitive CIR Expert Panel safety assessment. Concluded glycolic acid safe in consumer products at up to 10% concentration, pH 3.5 or greater, when product includes sun protection directions. Industry reference standard.

Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier

Fartasch M, Teal J, Menon GK.

Arch Dermatol Res

Definitive mechanistic study using electron microscopy. Showed that 4% glycolic acid causes targeted desmosomal breakdown in the stratum disjunctum while leaving the stratum compactum intact. TEWL did not increase, demonstrating exfoliation without barrier compromise.

Glycolic acid peels for postinflammatory hyperpigmentation in black patients. A comparative study

Burns RL, Prevost-Blank PL, Lawry MA, et al.

Dermatol Surg

Studied glycolic acid peels (up to 68%) specifically in Fitzpatrick IV-VI patients with PIH. Peels provided additional benefit beyond standard topical treatment with minimal adverse effects. Important for addressing underrepresented population in dermatological research.

Topical 8% glycolic acid and 8% L-lactic acid creams for the treatment of photodamaged skin. A double-blind vehicle-controlled clinical trial

Stiller MJ, Bartolone J, Stern R, et al.

Arch Dermatol

Double-blind vehicle-controlled RCT comparing 8% glycolic acid to 8% lactic acid for photodamaged skin over 22 weeks. Both acids modestly useful; 76% of glycolic acid users achieved at least one grade improvement. Glycolic showed slight edge over lactic.

A histological comparison of 50% and 70% glycolic acid peels using solutions with various pHs

Moy RL, et al.

Dermatol Surg

Demonstrated that 70% glycolic acid peels cause more tissue necrosis than 50% peels. Lower pH at these concentrations creates more tissue necrosis. Important for understanding professional peel safety margins.

Clinical and histological effects of glycolic acid at different concentrations and pH levels

Decker LC, Graber EM.

Dermatol Surg

Demonstrated histologically that skin irritation increases with concentration at a given pH and increases as pH decreases at a given concentration. Establishes the dual-variable model for glycolic acid dose-response.

Clinical improvement of photoaged skin with 50% glycolic acid. A double-blind vehicle-controlled study

Newman N, Newman A, Moy LS, et al.

Dermatol Surg

Double-blind vehicle-controlled study. Weekly 50% glycolic acid peels improved mild photoaging with histological confirmation of improvement.

Glycolic acid modulation of collagen production in human skin fibroblast cultures in vitro

Moy LS, Howe K, Moy RL.

Dermatol Surg

Showed dose-dependent collagen stimulation by glycolic acid in fibroblast cultures in vitro.

Effects of alpha-hydroxy acids on photoaged skin: a pilot clinical, histologic, and ultrastructural study

Ditre CM, Griffin TD, Murphy GF, et al.

J Am Acad Dermatol

Demonstrated that AHA treatment reversed histologic markers of photoaging in both the epidermis and dermis. Treated skin showed increased epidermal thickness, improved rete ridge pattern, and more evenly distributed melanin.

Guidelines of care for chemical peeling

Drake LA, et al.

J Am Acad Dermatol

Official AAD guidelines for chemical peeling. Recommends minimum 2-week interval between professional peel sessions, pre-peel skin preparation for 2-4 weeks, and medical history review before every peel.

Control of keratinization with alpha-hydroxy acids and related compounds. I. Topical treatment of ichthyotic disorders

Van Scott EJ, Yu RJ.

Arch Dermatol

Foundational AHA research. Tested 60+ substances for effects on keratinization. Alpha-hydroxy acids, particularly glycolic acid, demonstrated the most profound ability to normalize abnormal keratinization in patients with ichthyosis. Launched the field of AHA dermatology.

Chemical Peels - Patient Education Resource

American Academy of Dermatology.

American Academy of Dermatology

Official AAD patient education resource on chemical peels. Recommends peel neutralization based on visual assessment of erythema rather than fixed timer.