Arginine for the skin: what are the benefits?

As anamino acid, arginine is one of the fundamental units that make up protein constituents. At the cellular level, it is involved in several biological processes, including wound healing, immunity, and cell division. Moreover, arginine is involved in the production of nitric oxide NO, a compound that plays a role in stabilising blood pressure due to its vasodilatory effect. However, although nitric oxide plays a crucial role in maintaining the body's activities, an excessive amount can be harmful to heart health. This is why supplementation with arginine is not recommended for people who have had a heart attack.

This amino acid was first isolated in 1886 from a plant, the yellow lupin, by the German chemist Ernst SCHULZE and his assistant Ernst STEIGER. Thearginine presents itself as a white powder and can be used to formulate cosmetic treatments, intended for skin and hair. In fact, it is one of the most commonly used amino acids in the field of cosmetics.

• Arginine to prevent skin sagging?

  Arginine, or L-arginine, is regularly incorporated into products aimed at preventing skin ageing as it may have an effect on the suppleness and firmness of the skin. A study conducted on rats recently showed that the topical application of a glycerol solution containing 5, 10 or 15% arginine for fifteen days increased the elasticity of their skin. The most significant difference was observed following the application of the 15% arginine solution. Furthermore, in some mice, an increase in the number of collagen and elastin fibres was observed.

  The mechanism at work is still unclear and poorly understood. Indeed, it has been shown that arginine causes an increase in the activity of nitric oxide synthase, an enzyme inducing the production of nitric oxide NO. However, this molecule stimulates theexpression and activation of MMP-1 and MMP-2 in fibroblasts, matrix metalloproteinases responsible for the degradation of extracellular matrix compounds. This mechanism thus contradicts the result of the previously mentioned study. The authors conclude by hypothesising that a low dose of arginine can act on fibroblasts and stimulate the synthesis of collagen and elastin through a post-translational mechanism, without specifying which one.

  Conclusion : It thus appears challenging to determine the effect of arginine on skin ageing.

• Arginine to protect the skin from oxidative stress?

  Formed as a result of prolonged exposure to pollution, tobacco, but especially UV rays, the free radicals are harmful species that can oxidise lipids, proteins and DNA within cells. They thus cause genetic mutations and, at the skin level, they can be sources of melanomas and carcinomas. Antioxidant molecules help to neutralise the effects of free radicals and have a protective effect for the skin and the body.

  It has been demonstrated that arginine possesses a certain antioxidant capacity. A 14-day study conducted on rats revealed a boost in glutathione content, an endogenous antioxidant molecule, following daily administration of 50 mg/100g of body weight. The Nrf2 synthesis pathway, which plays a crucial protective role against oxidative stress, was also upregulated. These findings suggest that arginine availability is a critical factor in suppressing oxidative stress and enhancing the antioxidant response.

  Note : The studies conducted on the antioxidant activity of arginine have been carried out through oral intake. Further research would be necessary to conclude that the use of this amino acid in topical application also has antioxidant effects.

• Arginine to accelerate skin healing.

  The wound healing process involves numerous factors such as platelets, inflammatory cells, and epithelial cells. They all have one thing in common: they are capable of producing NO, either constitutively or in response to inflammatory cytokines. This plays a significant role in healing, from the inflammatory phase through to skin remodelling and has cytostatic, chemotactic and vasodilatory effects. It has also been shown that NO regulates the proliferation and differentiation of several types of cells and modulates angiogenesis, the process of blood vessel formation. By participating in the production of NO, arginine could contribute to effective skin healing.

  Please note : Caution should be exercised regarding the healing effect of arginine as, to date, this has not been demonstrated in clinical trials.

• GAD M. Z. Anti-ageing effects of l-arginine. Journal of Advanced Research (2010).

• MESHRAM A. & SRIVASTAVA N. Diverse potential and pharmacological studies of arginine. Journal of Proteins and Proteomics (2015).

• FATIMA BORIN M. & al. The in vivo impact of L-arginine on skin elasticity in mice. Brazilian Journal of Pharmaceutical Sciences (2017).