At what concentration does retinol become effective in a cosmetic product?

Several scientific studies have demonstrated the effectiveness of retinol against signs of ageing starting from 0.01%.

As a reminder, the retinol, also known as vitamin A, is a compound that belongs to the retinoid family. It is recognised for effectively acting on the visible signs of skin ageing such as wrinkles, pigmentation spots, or even loss of firmness and radiance. It stimulates cell renewal, tightens pores and refines skin texture. Sensitive to light, this active ingredient is preferably used in the evening, for greater effectiveness.

Note : The European Cosmetic Regulation permits the use of retinol in leave-on products at a maximum concentration of 0.3%. Be aware, overdosing this active ingredient could prove at best unnecessary, at worst dangerous. Indeed, at high concentrations, it can cause significant skin irritations.