What are the alternatives to retinol?

• Vitamin C.

  Primarily known for its antioxidant role, the vitamin C is also capable of stimulating collagen synthesis. Indeed, vitamin C acts as a cofactor for prolyl and lysyl hydroxylase enzymes, which are essential for the stabilisation and cross-linking of collagen fibres. Some research also reports that this molecule inhibits the expression of certain matrix metalloproteinases. Vitamin C thus appears to be a comprehensive active ingredient for delaying skin sagging.

  Several studies have highlighted the benefits of vitamin C for mature skin, including a study conducted in 2020 with 50 volunteers. These individuals applied a cream containing 20% vitamin C, vitamin E, and raspberry extract to one half of their face daily for two months. After eight weeks, an average reduction of 15.8% in wrinkle visibility was measured on the side where the cream was used, while no change was observed on the other. However, 50% of the participants experienced a tingling sensation when applying the cream, likely due to the high concentration of vitamin C.

To avoid irritations associated with the use of pure vitamin C, most skincare products today utilise vitamin C derivatives.

• Glycolic acid.

  The glycolic acid is a molecule belonging to the family of alpha-hydroxy acids, known for its action on wrinkles. Its effectiveness is based on several biological mechanisms. Firstly, due to its small molecular size, it easily penetrates the epidermis and stimulates cellular renewal, which helps to improve the skin's appearance and reduce wrinkles. Glycolic acid also has direct effects on stimulating the components of the dermal connective tissue, such as collagen and elastin. This active ingredient can also induce a slight controlled inflammatory response, which activates tissue repair processes and promotes the remodelling of the dermis. Finally, glycolic acid increases the levels of hyaluronic acid, thus promoting a more plump skin and a reduction in fine dehydration lines.

• Peptides.

  Peptides are powerful allies in combating wrinkles. Composed of amino acid chains, they play a crucial role in cellular communication by mimicking the natural signals that regulate the production of the skin's structural proteins. Certain peptides stimulate fibroblasts to increase the synthesis of collagen, elastin, and glycosaminoglycans, while others act as messengers to activate tissue repair pathways, thus promoting dermal renewal. There are also so-called enzyme inhibitor peptides, capable of limiting the activity of matrix metalloproteinases.

  A study was conducted on the effects of a moisturising cream containing 3 ppm of the peptide Pal-KTTKS on the signs of ageing in 93 volunteers. Divided into two groups, they applied the cream containing Pal-KTTKS or an equivalent without the active ingredient daily. A greater reduction in wrinkles (13.5% versus 11.6%) was observed in individuals who received the cream with the peptide. Although small, the difference between these reductions was deemed significant by the authors.

Finally, retinol is a molecule of interest for acne-prone skin. Indeed, due to its keratolytic action, it accelerates cellular renewal, which prevents the accumulation of dead cells on the skin's surface, one of the factors contributing to the formation of comedones. In doing so, retinol also promotes an aerobic environment that is inhospitable for Cutibacterium acnes, the primary bacteria involved in acne. However, retinol is not the only one capable of combating blemishes.

• Salicylic acid.

  The salicylic acid possesses keratolytic, antibacterial, and anti-inflammatory properties that are beneficial for skin imperfections. In addition to its inhibitory effect on the synthesis of prostaglandins E2, it curbs the production of sebum lipids by activating AMPK enzymes and SREBP-1 proteins. Furthermore, salicylic acid stands out for its liposoluble properties, allowing it to reach clogged pores and eliminate accumulated impurities. According to studies evaluating the effectiveness of an exfoliant containing 30% salicylic acid on 35 individuals, the average number of facial lesions decreased from 68.2 to 39 over 12 weeks. This study is far from being an isolated case, with others also highlighting the anti-imperfection virtues of this active ingredient.

• Succinic Acid.

  Gentler than salicylic acid, succinic acid is another relevant option for reducing blemishes. Its mechanism of action is quite similar, except that it cannot be considered a liposoluble active ingredient. Succinic acid can interfere with the activity of the sebaceous glands, thus limiting sebum production and preventing pore blockage. It also has antibacterial properties that allow it to target Cutibacterium acnes, as well as an exfoliating action.

  Recent studies have highlighted the potential of succinic acid in combating skin imperfections. For this, 43 volunteers with acne were recruited and used a daily lotion containing 4% niacinamide, 2% succinic acid, and extracts of tea and Morinda citrifolia. After 56 days, researchers observed a decrease in the abundance of C. acnes, along with a reduction of 52.12% in the number of inflammatory lesions and 18.33% in erythema. Furthermore, the lotion was well tolerated by all participants. Still relatively unknown, succinic acid deserves more attention for the care of acne-prone skin.

• Fruit acids.

  Fruit acids, also known as AHA (alpha-hydroxy acids), are particularly beneficial for skin prone to blemishes due to their exfoliating action. By weakening the bonds between dead cells in the horny layer, they promote their elimination and accelerate cell renewal, thus helping to unclog pores and reduce the formation of comedones. One of the most well-known AHAs is glycolic acid, but there are others, such as the lactic acid, appreciated for its gentleness and the hydration it provides to the skin, or the mandelic acid. The latter also has antibacterial and anti-inflammatory properties, making it a comprehensive active ingredient to reduce blemishes.