Tretinoin
Also known as Retin-A, all-trans retinoic acid
The most studied topical for photoaging and acne. Slow, unglamorous, and genuinely effective if you survive the first three months.
Generic tretinoin cream is typically $10–30/tube; branded formulations run higher.
How it works
A vitamin A derivative that binds retinoic acid receptors in keratinocytes, accelerating cell turnover, normalising follicular keratinisation and upregulating type I and III collagen synthesis while inhibiting matrix metalloproteinases that degrade existing collagen.
How it's used
Start at 0.025% two or three nights per week on completely dry skin. Pea-sized amount for the whole face. Buffer with moisturiser if irritated. Increase frequency before increasing strength. Daily SPF is non-negotiable — retinoids thin the stratum corneum and increase photosensitivity.
Trade-offs
In favour
- Strongest evidence base of any topical anti-ageing agent
- Treats acne and photoaging simultaneously
- Cheap as a generic
- Improves texture, tone and fine lines over time
Against
- Retinisation period of 8–12 weeks with peeling, redness and purging
- Requires indefinite use to maintain gains
- Prescription-only in most countries
- Not compatible with pregnancy
Risks and side effects
- Contraindicated in pregnancy (teratogenic)
- Severe irritant dermatitis if over-applied
- Photosensitivity — sunburn risk rises materially
How good is the evidence?
Multiple randomised controlled trials and decades of dermatological guideline support for both acne and photoaging.
Sources
- Acne vulgaris management guidelinesAmerican Academy of Dermatology · 2024
- Topical tretinoin for photoaged skin — trial literaturePubMed
Sources point to guideline bodies and literature searches rather than single papers, so they stay accurate as the evidence moves.