Retinol vs retinal vs adapalene: which one should you use?

Retinal (retinaldehyde) is one conversion step closer to retinoic acid than retinol, so on paper it’s the stronger of the two, while still being a shop ingredient. Adapalene is a different thing: a lab-made acne retinoid that acts on retinoid receptors directly. Tretinoin is retinoic acid itself, prescription only.

One idea makes the whole family click: your skin responds to retinoic acid. Everything on the shelf is either a step on the way to it or a molecule built to act like it. Count the steps and you can roughly predict how strong a product is and how likely it is to sting.

Retinol vs retinal: what’s the difference?

Retinol needs two oxidation steps to become retinoic acid: first into retinal, then into retinoic acid. Retinal skips the first one. Retinyl esters, like retinyl palmitate and retinyl acetate, add a step at the very start, because the ester has to be split off before anything else can happen. A 2019 review in Advances in Dermatology and Allergology puts the end of the ladder in perspective: retinoic acid is roughly 20 times more powerful than retinol.

Types of retinoids compared: strength, irritation, where to buy

Retinal vs retinol: which is better?

On paper, retinal should win, and the little human evidence there is points the same way. In a 2021 split-face trial, 23 Korean adults put a retinal cream (0.05% or 0.1%) on one side of the face and retinol at the same strength on the other for 8 weeks. Both sides improved on wrinkle depth, hydration and elasticity, the retinal side improved more on most measures, and nobody reported side effects. That’s one small study of one formula, though. Think of retinal as a sensible next step once retinol feels easy, not a sure upgrade.

Why retinoid percentages don’t compare

A bigger number on a retinol doesn’t make it stronger than a retinal with a smaller one. Each step on the ladder changes how much ends up as retinoic acid, so a percentage only compares within the same form. And for medicines, small numbers are strong numbers: tazarotene works at 0.05% to 0.1%, adapalene at 0.1%.

Adapalene vs tretinoin: the acne retinoids

Adapalene is selective: it targets particular retinoid receptors, which is part of why DermNet rates it the least irritating of the retinoid medicines. Tretinoin is the original, with nothing to convert, more power and usually more peeling. A 2006 review calls tretinoin the most widely studied retinoid for photoaging, so it’s the one with the deepest evidence for lines and sun damage. For clogged pores and breakouts, adapalene is the usual first step.

Where can you buy adapalene?

Where you live matters. In the US, adapalene 0.1% gel moved from prescription to over the counter in July 2016, and in May 2026 the FDA approved an over-the-counter gel that combines adapalene 0.1% with benzoyl peroxide 2.5%. In the UK and most other countries, adapalene is still prescription only. Tretinoin and tazarotene need a prescription in every country Nubia is in.

Trend check: bakuchiol and HPR

Bakuchiol is a plant compound, not a retinoid, sold as a retinol alternative. The trial most people quote is a 12-week, double-blind study of 44 people in the British Journal of Dermatology (2019): bakuchiol 0.5% twice a day and retinol 0.5% once a day both reduced wrinkle area and hyperpigmentation, with no statistical difference between them, and the retinol group reported more scaling and stinging. Promising, but it’s one small trial.

HPR (hydroxypinacolone retinoate) is an ester of retinoic acid that’s marketed as a low-irritation retinoid. Most published human studies test it blended with retinol, peptides or other retinoids, so it’s hard to tell what HPR does on its own, and the big claims are still early.

Which retinoid should you start with?

Whichever one you choose, Nubia gives it a couple of nights a week to begin, on nights of its own, and waits for your check-ins to say your skin’s happy before it adds another.

Safety note: Pregnant, trying to conceive or breastfeeding? Nubia keeps every retinoid out of your routine, adapalene included, unless your clinician says otherwise.