The combinations of vitamins to prioritise.

The combination of these two active ingredients is safe and offers several benefits. Firstly, let's briefly recall the benefits of each vitamin:

• Vitamin A (or retinol) is considered one of the most effective compounds to combat signs of ageing. Its actions are manifold: it stimulates collagen production, reduces the appearance of brown spots, activates cell renewal, and limits oxidative stress.

• Vitamin B3 (or niacinamide) aids in restoring the skin's barrier function and contributes to the healing process. It diminishes marks and redness left by blemishes, such as post-acne marks. Thanks to its anti-inflammatory properties, niacinamide is a preferred active ingredient for improving the overall appearance of blemish-prone skin.

Niacinamide is a gentle active ingredient that is well tolerated by all skin types. Retinol, on the other hand, is more drying and can cause irritation in individuals with sensitive or even atopic skin.

Niacinamide helps to combat the drying effect of retinol and maintains a good level of hydration in the epidermis due to its strengthening action on the hydrolipidic film.

Furthermore, due to their mutual benefits, the retinol/niacinamide combination is particularly suitable for individuals with some wrinkles, as well as blemishes.

In the evening only, on a clean and dry face, we recommend first applying a few drops of the unifying serum with 12% niacinamide, followed by a few drops of the wrinkle & fine lines serum containing 0.3% retinol.

These two vitamins will act differently to limit the appearance of brown spots:the vitamin C inhibits tyrosinase, an enzyme necessary for the production of melanin, while the niacinamide blocks the transfer of pigments into the cells.

Regarding application, there is no preferential order for applying these two actives on your skin. Prioritise the care with the least thick, most fluid texture first. Thus, a serum is generally applied before a cream with a higher viscosity. For example, for a luminous, smooth and uniform complexion, we advise you to apply morning and evening the unifying serum with 12% niacinamide, then subsequently, the antioxidant face cream based on vitamin C and lemon extract.

Researchers have demonstrated that vitamins C and E, when combined in a single skincare product, can prevent acute damage caused by ultraviolet (UV) rays such as sunburn, as well as photoaging (accelerated skin ageing due to sun exposure) and the risk of skin cancer. Furthermore, these two vitamins are effective depigmenting agents that limit the appearance of brown spots.

Furthermore, the vitamin E, due to its antioxidant properties, stabilises vitamin C in a skincare product, allowing it to remain active for a longer period. As such, many vitamin C serums contain vitamin E (tocopherol). When applied to the hair, a treatment combining vitamins C and E will invigorate the hair fibre while protecting it from external aggressors.

Firstly, let's clarify that despite its name, vitamin F is not a vitamin but a combination of two essential fatty acids: linoleic acid and linolenic acid. It repairs and preserves the skin's barrier function. To restore suppleness to the epidermis, we have combined vitamins E and F in our replenishing shower oil. Vitamin E or tocopherol protects the skin from the damage caused by free radicals.

• KIMBALL A. B. & others. Topical vitamins, minerals and botanical ingredients as modulators of environmental and chronological skin damage. British Journal of Dermatology (2003).

• SHEA C. R. & co. UV photoprotection through the combined use of topical antioxidants vitamin C and vitamin E. Journal of the American Academy of Dermatology (2003).

• BURKE K. E. Interplay of Vitamins C and E as Superior Cosmeceuticals Dermatology and Therapy (2007).

• WAN Y. & al. Nicotinamide reduces overexpression of aquaporin 3 induced by retinoic acid via inhibition of EGFR/ERK in cultured human skin keratinocytes. International Journal of Molecular Medicine (2008).

• BAGATIN E. & al. Cosmeceutical vitamins. Clinics in Dermatology (2009).