Collagen regimen: what are the benefits for the skin?

The oral consumption of collagen is said to have significant skin benefits, particularly against the acceleration of skin ageing. A study conducted by Steffen OESSER evaluated the effectiveness of collagen peptides on the formation of eye contour wrinkles and the stimulation of the biosynthesis of procollagen I, a precursor of collagen, of elastin and fibrillin in the skin. One hundred and fourteen women aged between 45 and 65 were given 2.5g of collagen or a placebo, once a day for eight weeks. Skin wrinkles were measured before the start of the treatment, and after four and eight weeks.

The ingestion of collagen resulted in a significant reduction in the volume of eye wrinkles (20%) compared to the placebo group after four and eight weeks of intake. Furthermore, after 8 weeks of intake, a statistically higher content of type I procollagen (65%) and elastin (18%) was detected in the volunteers treated with collagen compared to patients treated with placebo. For fibrillin, a non-significant increase of 6% could be determined in the collagen group compared to the placebo. In conclusion, these results demonstrate that the oral intake of collagen peptides reduces wrinkles around the eyes and has positive effects on the synthesis of the dermal matrix.

A possible explanation for this improvement could be the increase in the biosynthesis of essential dermal macromolecules such as collagen, elastin, and fibrillin. Collagen and elastin are the main components of the dermis that help to maintain the structure, firmness, and elasticity of the skin, and they directly affect wrinkle formation. Indeed, an alteration of the fibres occurs in the dermis of wrinkled skin. Therefore, oral intake of collagen can increase the synthesis of essential macromolecules for maintaining skin elasticity, and thus reduce and prevent signs of ageing.

Furthermore, studies have demonstrated a antioxidant effect of collagen when taken orally. During oxidative stress caused by tobacco, pollution or UV rays, the production of free radicals is observed. These species cause significant damage such as the acceleration of skin ageing. Researchers have found that oral collagen intake can prevent the reduction of the activity of antioxidant enzymes such as superoxide dismutase (SOD). These enzymes have the role of neutralising free radicals, and preventing them from acting on the skin. In addition, free radicals activate the MAPK signalling pathway and the AP-1 protein to increase the expression of matrix metalloproteinases (MMP) and promote the degradation of the matrix's collagen. Studies have proven that the consumption of collagen inhibits the expression of MMP-1 and MMP-3.

Through the promotion of the biosynthesis of matrix macromolecules and antioxidant action, the consumption of collagen could therefore slow down skin ageing.

Masashi OGO and his colleagues sought to investigate the effect of orally ingested collagen peptides on skin hydration status. A trial was conducted on 99 Japanese women, randomly divided into three groups to receive either 1 or 5 g of collagen peptides or a placebo once a day for 12 weeks. Skin water content and transepidermal water loss (TEWL) were assessed before treatment and after 4, 8 and 12 weeks of treatment. The level of natural moisturising factors (NMF) in the stratum corneum was quantified before treatment and after 12 weeks of treatment. The ingestion of collagen increased water content and reduced water loss. Furthermore, the level of NMF in the stratum corneum increased.

The enhancement of the skin's water content following the oral ingestion of collagen can thus be attributed to an increase in the level of NMF in the stratum corneum. Natural Moisturising Factors are hygroscopic substances responsible for maintaining hydration in the stratum corneum of the epidermis. The amino acids contained in the NMFs are predominantly derived from the proteolysis of filaggrin, a skin protein. The NMFs contain also hyaluronic acid, known for its moisturising properties.

Furthermore, oral collagen boosts the synthesis of filaggrin. Oral ingestion of collagen has been found to improve TEWL (Transepidermal Water Loss). This is consistent with the enhancement of filaggrin expression, which is believed to play a role in maintaining the internal structure of keratinocytes and, consequently, in their barrier functions against water loss, but also in the production of NMFs (Natural Moisturising Factors), which then stimulate skin hydration.

Most scientific studies on the benefits of oral collagen intake focus on supplementation in the form of dietary supplements. However, collagen is also found in the foods we consume daily. Many people adopt what is known as the collagen diet. This is a diet that favours foods rich in collagen. Among these foods, we notably find bone broths, meat, and eggs. Other foods can stimulate collagen production, due to their richness in vitamin C, such as citrus fruits, red fruits, and peppers.

Nevertheless, almost no study has focused on a specific effect of a collagen regimen on the skin. Therefore, we cannot assert with certainty any particular skin benefits in this situation.

Furthermore, the majority of studies on the effects of collagen on the skin have been conducted by brands. Therefore, there may be biases present, so these results should be approached with caution.

• OESSER S. & al. Oral intake of specific bioactive collagen peptides reduces skin wrinkles and increases dermal matrix synthesis. Skin Pharmacology and Physiology (2014).

• OGO M. & al. Oral supplementation of collagen peptides improves skin hydration by increasing the natural moisturizing factor content in the stratum corneum: A randomized, double-blind, placebo-controlled clinical trial. Skin Pharmacology and Physiology (2021).

• GE C. & al. Oral Intake of Chicken Bone Collagen Peptides Anti-Skin Aging in Mice by Regulating Collagen Degradation and Synthesis, Inhibiting Inflammation and Activating Lysosomes. Nutrients (2022).