When should you start using retinol?

There's no single right age to start retinol. The real question isn't how old you are, but what you're trying to do and how much your skin can handle. The evidence that retinoids improve sun-related aging is fairly solid (Mukherjee et al., 2006; Kafi et al., 2007). You can begin in your twenties at a low strength to get ahead of it, but sunscreen and moisture come first. Starting gently matters more than starting early.

Is there a set age to start retinol?

People often say retinol is "for your thirties," but dermatology hasn't fixed a starting age. What matters more is what you want and how well your skin tolerates it. Some people want to soften lines that have already settled in; others have no concerns yet and simply want to get ahead of them. Rather than using your age as the marker, it's more realistic to go by your goals and your skin's tolerance. When aging first crosses your mind, retinol is easy to fixate on, but the bigger picture starts with how to prioritize prevention.

What's the upside of starting early in your twenties?

Much of what we call skin aging comes less from age itself than from sun exposure adding up over time. Collagen begins its slow decline from around the mid-twenties, a shift covered more closely in collagen loss from age 25. Retinoids act on this process and have been reported to improve the texture and fine lines of sun-aged skin (Mukherjee et al., 2006). Even pure retinol has been shown to ease fine wrinkles in naturally aged skin (Kafi et al., 2007). So starting low in your twenties is more about losing less later than about undoing what's already there. Just keep in mind that results are slow, so give it a few months rather than a few weeks.

So how should you actually start?

Begin at a low strength, two or three nights a week. The goal is to give your skin time to adjust, not to pile on more product. Retinol can leave skin more sensitive to daylight, so morning sunscreen is essentially non-negotiable. If you'd like to use vitamin C as well, a simple approach is vitamin C in the morning and retinol at night; the order and pairing are laid out in using vitamin C and retinol together. If you notice stinging, flaking, or redness, it's safer to cut back the frequency before the strength. One more note: if you're pregnant or breastfeeding, it's best to skip retinol and choose something else.

Is it okay not to rush?

Starting retinol sooner doesn't hold off aging by the same margin. Pushing hard while your barrier is weak or easily irritated can cost you more than it gives. With retinol, keeping it gentle over the long run matters more than starting early. Once the basics of sunscreen and moisture are in place, retinol can finally do its part. If you're weighing when to begin, you already care about your skin, so keep that pace.

One thing today

• Make morning sunscreen the habit you keep first. Check week by week whether there were mornings you skipped it; retinol makes skin more sensitive to light.
• Start retinol low, two or three nights a week. In a trial, 0.4% retinol lotion used up to three times a week for 24 weeks improved fine lines (Kafi et al., 2007). Judge it at around six months, not a few weeks.
• If it stings, lower the frequency before the strength. The test is whether the next application stings less after you cut the frequency. If it does not, that is when you lower the strength.