“Retinol is an active that oxidises when it comes into contact with air and sunlight. It has to be prepared and transported at very low temperatures in an oxygen free environment,” explains Paula Begoun, founder of the brand Paula’s Choice. “Which is a huge challenge!” The doctor Nadine Pomarède, dermatologist and founder of the Dermo Medical Center in Paris and Brussels adds, : “The problem with retinol is keeping it stable enough to be effective.” Which explains why you need to choose this super powerful yet fragile ingredient carefully and keep it a maximum of three months.

Kat Burki, founder of the eponymous brand advises “applying retinol at night so as to protect it from sunlight.” Valérie Leduc, a specialist in cosmetic medicine and cofounder of Maison Epigenetic in Paris also advises “always applying it at night on clean, dry skin so as to avoid irritation.”

And how much?

Levels of concentration vary from 0,01 to 1 %. So how should you choose the version that’s right for you? “It has been shown that low levels of retinol (as low as 0,01 % for example) can be useful in preventing or reducing minor skin issues. Higher concentration levels (so up to 1 %) can be effective on more tenacious imperfections, such as sun damage, deep wrinkles, sagging and acne,” explains Paula Begoun.

It’s not about age but rather about what your skin needs. Originally used to treat acne (and therefore often used on young skin), retinol also works wonders on the signs of age and older skin. Regarding anti-ageing treatments, Kat Burki recommends using it preventatively from “20 to 30 to minimise the appearance of fine lines and wrinkles.”

“A retinol based product can be used with any combination of skincare products,” explains Paula Begoun. “It works perfectly with other products.” Kat Burki adds, “it’s important that retinol is absorbed swiftly. It’s better when it’s not too viscous. Oils and creams can prevent swift absorption so it’s better to apply them after applying retinol.”

But the best combinations are often the simplest. Nadine Pomarède explains: “You can combine it with other antioxidants such as vitamins C and E for complete antioxidant action. You can also use it with hyaluronic acid which has an anti-ageing effect and is also hydrating and helps to counterbalance the drying effect of retinol, especially when you first start to use it.” If you have very sensitive skin it’s best to use it with anti-inflammatory products like “hyaluronic acid, vitamin E, green tea or jojoba oil,” advises Valérie Leduc.