Retinol is vitamin A. Skin converts it in steps: retinol becomes retinaldehyde (retinal), and that becomes retinoic acid, which is the prescription drug tretinoin2. That extra conversion is why over-the-counter retinol is gentler and slower than a prescription. The AAD says retinol is routinely used to improve uneven tone, pigmentation and texture1.
The rules that come from the sources
- Use the lowest strength you can find. Retinol percentage does not have to be on the label, so check the pack1.
- Use it at night only, and wear sunscreen in the morning. Retinoids can make skin more sensitive to the sun13.
- Start every other night at most. The AAD's dermatologist says to build up slowly, otherwise people end up irritating their skin1. Cleveland Clinic says to apply it only every other day for the first couple of weeks4.
- Use a pea-sized amount for the whole face, and moisturise afterwards4.
- Do a patch test first4.
| When | Nights a week | Notes |
|---|---|---|
| Weeks 1 and 2 | 2 (say Monday and Thursday) | Gentler than the alternate-night advice in the sources |
| Weeks 3 and 4 | 3 | Leave a night off between uses |
| Week 5 on | Every other night, or nightly | Only if your skin is comfortable |
Mixing it with other actives
Cleveland Clinic advises alternating glycolic acid and retinol, on different days or glycolic in the morning and retinol at night, because both can irritate4. The wider rule, no retinol and an exfoliating acid on the same night when you are new to actives, is common practice rather than a trial result. We follow it because the downside is only a slower start.
What to expect, and how long it takes
Some dryness, flaking or redness in the first weeks is common. Cleveland Clinic says visible change takes several weeks, and several months for wrinkles4. In a 24-week trial, a 0.4% retinol lotion applied up to three times a week reduced fine wrinkling on the arms of elderly volunteers compared with a plain lotion5. If your skin stings, is red or flakes badly, take a break. If you have darker skin, irritation can leave dark marks, so slow starts matter more1.
Who should not use it
- Anyone who is pregnant or trying to conceive. The AAD says retinoids should not be used during pregnancy, including retinol in skin care6. The UK teratology service advises the same as a precaution for retinoid creams, because high-dose oral retinoids cause birth defects7.
- If you are breastfeeding, ask your doctor. The sources we read do not give a clear answer.
- People with rosacea, eczema or moderate to severe acne scarring should speak to a dermatologist first1.
