Tretinoin

Also known as: retinoic acid, all-trans retinoic acid, Retin-A

Tretinoin is prescription-strength vitamin A acid and the most studied topical anti-aging and acne drug in dermatology, with FDA approval for both uses. It has decades of randomized controlled trials behind it, including recent meta-analyses pooling over 1,300 patients for photoaging alone. It is the benchmark that other retinoids, including over-the-counter retinol, are measured against. The main tradeoffs are irritation in the first 4 to 8 weeks and the need for a prescription in most countries.

How it works

Tretinoin binds directly to retinoic acid receptors in skin cells, changing which genes are switched on. That speeds up skin cell turnover (which keeps pores from clogging), increases collagen production in the dermis, and disperses melanin pigment more evenly. Because it is already the active form of vitamin A, it needs no conversion in the skin, which is why it works faster and stronger than retinol.

What the evidence says, claim by claim

These are the results measured in studies, not the results shown in ads. Where the research is weak, the grade says so.

For acne

Strong evidence

A meta-analysis of 3 randomized, double-blind, vehicle-controlled trials in 629 patients aged 11 to 49 found tretinoin microsphere gel 0.04% significantly reduced both inflammatory and noninflammatory lesions over 12 weeks versus vehicle. Tretinoin is a first-line acne treatment in major dermatology guidelines, with consistent results across formulations from 0.025% to 0.1%.

Multiple randomized controlled trials or a meta-analysis support this use. The effect is real and repeatable.

Tretinoin microsphere gel in facial acne vulgaris: a meta-analysis (Journal of Drugs in Dermatology, 2008; meta-analysis)

For wrinkles and fine lines

Strong evidence

A 2025 meta-analysis of 8 randomized trials in 1,361 patients (follow-up 16 weeks to 2 years) found tretinoin significantly improved fine wrinkles versus vehicle (mean difference 0.412, 95% CI 0.233 to 0.590). An earlier systematic review of 7 RCTs found consistent improvement in wrinkling, mottled pigmentation, and sallowness starting around 1 month and holding up to 24 months, at concentrations from 0.025% upward.

Multiple randomized controlled trials or a meta-analysis support this use. The effect is real and repeatable.

Tretinoin for Photodamaged Facial Skin: Systematic Review and Meta-Analysis of Randomized Controlled Trials (Dermatology Practical & Conceptual, 2025; meta-analysis)
Topical tretinoin for treating photoaging: A systematic review of randomized controlled trials (International Journal of Women's Dermatology, 2022; systematic-review)

For melasma

Moderate evidence

A 2022 meta-analysis of randomized, investigator-blinded trials found tretinoin effective at lightening melasma as monotherapy, though the triple combination cream (hydroquinone plus tretinoin plus a corticosteroid) consistently outperformed single agents. As a standalone treatment it works more slowly than hydroquinone, often needing 24 weeks or more, so it is usually a supporting player rather than the lead.

Randomized trials support this use, but they are few, small, or short. The effect is probably real. The size of it is less certain.

Self-applied topical interventions for melasma: a systematic review and meta-analysis of data from randomized, investigator-blinded clinical trials (British Journal of Dermatology, 2022; meta-analysis)
Melasma Treatment: An Evidence-Based Review (American Journal of Clinical Dermatology, 2020; systematic-review)

Risks and what can go wrong

Expect redness, peeling, dryness, and stinging in the first weeks (the retinoid uglies); in the microsphere gel meta-analysis these occurred in about 60% of users, mostly mild. It increases sun sensitivity, so daily sunscreen matters. Oral retinoids cause birth defects, and although absorption through skin is minimal, topical tretinoin is still not recommended during pregnancy or breastfeeding. People with eczema or rosacea-prone skin may not tolerate it.

The practical details

Prescription only in the US, in strengths of 0.025%, 0.05%, and 0.1% (cream, gel, or lotion). Standard advice: pea-sized amount at night on dry skin, starting 2 to 3 nights per week and building to nightly as tolerated, with moisturizer and morning sunscreen. Visible acne results typically take 8 to 12 weeks; wrinkle improvement takes 3 to 6 months.