Retinol (vitamin A) is the superstar active ingredient in cosmetics with efficacy proven by various clinical studies:
- Preserves the collagen present by inhibiting the destructive enzymes matrix metalloproteinases (MMP, which are increased by UVB) and stimulates the production of collagen in the skin for firmer skin as well as those of other important elements of the skin, eg. glycosaminoglycans (GAGs), natural moisturizing factors, or filaggrin for younger looking skin.
- Activates cell renewal: dead cells are replaced with new cells for brighter looking skin
Anti stain properties:
Retinol also reduces dark spots by blocking the transfer of melanin to epidermal cells and by reducing the activity of melanocytes as well as accelerating cell renewal.
Anti acne properties:
Retinol also has an anti-acne effect by reducing the size and secretion of the sebaceous glands and by activating cell renewal.
Retinol is used in cosmetics at percentages between 0.01 to 1%. There are no restrictions on its use but higher percentages will not be authorized by toxicologists, the SCCS recommends a % of 0.3% in order not to exceed the maximum daily dose of vitamin A because it has side effects if this dose is exceeded.
Retinol is part of the retinoid family comprising the following forms:
Only the forms: retinol esters, retinol and retinal are authorized in cosmetics. Retinal is more difficult to formulate and therefore more rarely used. Retinol to work in the skin must convert to retinal and then to retinoic acid. It is only retinoic acid that has the beneficial effects. The more there are conversions, the more the effectiveness for the skin is reduced but the irritating effects are also. Retinol is recommended for use in the evening because it is not very stable against light and heat, which is why it is necessary to have airless packaging.
Note: Retinyl palmitate is an antioxidant widely used to protect a cosmetic formula from oxidation and also to support UV filters in sunscreen products.
- Retinoids in the treatment of skin aging: An overview of clinical efficacy and safety, Clinical Interventions in Aging, 2006
- Retinoids: active molecules influencing skin structure formation in cosmetic and dermatological treatments, Advances in Dermatology and Allergology, 2019
- A comparative study of the effects of retinol and retinoic acid on histological, molecular, and clinical properties of human skin, Journal of Cosmetic Dermatology, 2016