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Head-to-head evidence comparison — which supplement is right for you?
Hydroquinone wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Topical cosmetic only. Leave-on glycolic acid is used at roughly 5-15% in lotions/serums (often at low pH), applied to clean skin a few nights per week and building as tolerated; professional peels (20-70%) are applied in-office at intervals. There is no oral, injectable, or systemic dose — it is not ingested. Pair with daily sunscreen. This library does not provide an ingestion protocol.
evening
Leave-on lotion or serum (≈5-15% glycolic acid)
Prescription topical. Hydroquinone is used at 2-4% (often as the triple-combination with a retinoid and a mild corticosteroid), applied to pigmented areas usually at night, in time-limited courses (commonly with treatment breaks) under clinician supervision, always with daily sunscreen. There is no oral or systemic use. Avoid indefinite continuous use because of ochronosis risk. This library does not provide an ingestion protocol.
evening
Hydroquinone 2-4% cream or the triple-combination (with retinoid + mild steroid), under a clinician
Throughout
8-12 weeks
8-16 weeks
First weeks
Throughout
8-12 weeks
Throughout
Months to years
A double-blind randomized clinical trial on the effectiveness of a daily glycolic acid 5% formulation in the treatment of photoaging.
Dermatol Surg (1998) · Rct · n=75
75 volunteers applied 5% unneutralized glycolic acid cream or placebo to face and neck daily for 3 months (double-blind, randomized, placebo-controlled)
Clinical improvement of photoaged skin with 50% glycolic acid. A double-blind vehicle-controlled study.
Dermatol Surg (1996) · Rct · n=41
41 volunteers received a 50% glycolic acid peel vs vehicle weekly for 4 weeks (in-office peel strength)
Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier.
Arch Dermatol Res (1997) · Open label
Electron-microscopy study of human skin after 3 weeks of 4% glycolic acid twice daily
Efficacy and safety of a new triple-combination agent for the treatment of facial melasma.
Cutis (2003) · Rct · n=641
Two pooled 8-week multicenter randomized investigator-blind trials (n=641) of the triple-combination (tretinoin 0.05% + hydroquinone 4% + fluocinolone 0.01%) vs the three dual pairings
Efficacy and safety of a novel triple combination cream compared to Kligman's trio for melasma: A 24-week double-blind prospective randomized controlled trial.
J Eur Acad Dermatol Venereol (2023) · Rct · n=40
24-week double-blind RCT (n=40) using Kligman's trio (hydroquinone + retinoic acid + corticosteroid) as the active gold-standard comparator
Systematic review of randomized controlled trials on interventions for melasma: an abridged Cochrane review.
J Am Acad Dermatol (2014) · Systematic review
Abridged Cochrane review of 20 RCTs (2125 participants) across 23 melasma treatments
Hydroquinone has a higher evidence score (7/10 vs 6/10) and wins in 2 of 3 categories.
For even skin tone, Hydroquinone has a higher relevance score (85 vs 60).
No known interactions between Glycolic Acid and Hydroquinone have been documented in our database. However, always consult a healthcare provider before combining supplements.