How to use collagen?

Collagen is a fibrous protein found in various body structures such as the skin, cartilage, ligaments or hair. It is also present in numerous cosmetic treatments, primarily for the skin, although some hair-care products are collagen-based. Typically incorporated at 1–2% in these formulations, this molecule helps to boost the skin’s hydration levels by forming a film on its surface. Furthermore, collagen attracts and retains water molecules, thereby protecting the epidermis from dehydration.

In addition to these hydrating properties, the antioxidant effects of collagen, making its use popular in formulations aimed at preventing wrinkles. As demonstrated with collagen hydrolysate, these effects are all the more significant when the peptides have a low molecular weight. Penetrating the skin more readily than the native molecule, collagen peptides can also activate fibroblasts, thereby stimulating the production of collagen, elastin and glycosaminoglycans. This enhances the skin's suppleness, elasticity and hydration.

How to use collagen? : The collagen is an active ingredient well tolerated by the skin and poses no risk of photosensitisation. It can therefore be used morning and evening, without any special precautions, alongside other skincare products. You simply need to follow the specific instructions for each product, notably the recommended frequency and method of application provided by the manufacturer.

In recent years, collagen has also entered the sphere of nutricosmetics. Drinkable collagen, collagen powder to dilute, collagen capsules… It is available in numerous forms, all promising similar benefits: a brighter complexion, more supple skin and stronger hair and nails strengthened. However, one may question the actual effects of these collagen regimens. Indeed, once the protein is ingested, it is broken down into amino acids in order to cross the intestinal barrier. These amino acids can then be utilised by the body to rebuild proteins, but there is no guarantee they will specifically form collagen. The same applies to collagen peptides, which are likewise hydrolysed into amino acids.

Despite these uncertainties, numerous studies have investigated the effects of collagen on skin and hair, revealing favourable outcomes for skin hydration and elasticity, wrinkle appearance, and hair and nail health. With regard to the recommended collagen dosage, it ranges between 2 and 15 g per day. According to studies, the benefits of collagen supplementation may become apparent after two weeks. The duration and frequency of these programmes vary considerably. Suppliers typically recommend a collagen supplementation programme of three to six months once a year, or two to three one-month courses annually.

Although oral collagen supplementation is generally well tolerated, it is advisable to seek medical advice before commencing a course, particularly if you have any food allergies.

Is there evidence for the efficacy of oral collagen in maintaining skin health?

Several studies have assessed the effects of collagen supplementation on the skin. One placebo-controlled study involving 114 women aged 45 to 65 years examined the efficacy of bioactive collagen peptides in reducing periocular wrinkles and stimulating the synthesis of structural proteins in the dermis. Participants received either 2.5 g of collagen peptides or a placebo once daily for 8 weeks. Objective assessment of wrinkle volume was performed before treatment and after 4 and 8 weeks of supplementation. A subgroup also underwent suction skin biopsies to measure the production of procollagen I, elastin and fibrillin, key proteins of the dermal matrix.

The results show a significant reduction of around 20% in the volume of periorbital wrinkles after eight weeks of supplementation compared with placebo. The beneficial effect persisted for four weeks following discontinuation, suggesting a prolonged action on dermal structure. Histological analyses revealed a 65% increase in type I procollagen and an 18% increase in elastin in the collagen peptide group, while fibrillin rose by 6%, not reaching statistical significance. These findings therefore support the idea that regular oral intake of hydrolysed collagen can stimulate the neosynthesis of dermal proteins and enhance skin firmness and texture.

Is there scientific evidence supporting the efficacy of oral collagen supplements for hair care?

The benefits of ingestible collagen for hair have also been assessed. A 2024 study examined the effects of an oral supplement containing hydrolysed collagen and vitamin C on hair health. Participants were monitored over 12 weeks and took the collagen capsule daily. Hair evaluation was performed using a combination of clinical trichoscopy, hair counts, and an imaging system that magnified the scalp surface and follicles up to 60 times, enabling observation of inflammation, scaling and follicular blockage. Measurements were recorded at the start of the study, at 6 weeks and at 12 weeks.

After 12 weeks of daily use, the results showed a mean improvement of 27.6% in the total number of hairs per unit area compared with the placebo, although this difference did not reach statistical significance. Clinical analysis revealed a significant 31.9% increase in the healthy hair appearance score, assessed by an expert on a five-point scale. Moreover, 66.7% of participants perceived their hair as thicker compared with 44.2% in the placebo group. These nuanced results suggest that oral supplementation with hydrolysed collagen and vitamin C could improve perceived hair density and overall appearance over a 12-week period, but further research is needed. Additionally, the supplement studied did not contain collagen alone, so the observed effects cannot be attributed to this single active ingredient.

What evidence exists for the effectiveness of oral collagen in caring for one’s nails?

Finally, collagen supplements are often used to improve nail appearance. A double-blind study was conducted on 54 women with brittle, splitting nails to assess the impact of an oral supplementation combining collagen, peptides and hyaluronic acid. Participants were split into two groups: one receiving the active formulation and one receiving a placebo. The results, shown in the table below, indicate that the supplemented group achieved a slightly greater improvement compared with the placebo group.

However, it is important to note that participants in the placebo group also observed a notable improvement in the condition of their nails. This observation suggests that some effects may be attributed to a placebo effect, and that the limited sample size (54 participants) prevents any definitive conclusions from being drawn. Further studies, involving a larger cohort of volunteers and a rigorous protocol, are required to confirm the efficacy of collagen supplementation on nail health.

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

• GANS E. H. & al. A nutritional supplement formulated with peptides, lipids, collagen and hyaluronic acid optimizes key aspects of physical appearance in nails, hair and skin. Journal of Nutrition and Food Sciences (2014).

• RODRIGUEZ M.I. Collagen: A review on its sources and potential cosmetic applications. Journal of Cosmetic Dermatology (2018).

• AHUIRRE-ÁLVAREZ G. & al. Collagen hydrolysates for skin protection: Oral administration and topical formulation. Antioxidants (2020).

• CHEN C. & al. Effects of oral collagen for skin anti-aging: A systematic review and meta-analysis. Nutrients (2023).

• LACEBY D. & al. A clinical trial shows improvement in skin collagen, hydration, elasticity, wrinkles, scalp, and hair condition following 12-week oral intake of a supplement containing hydrolysed collagen. Dermatology Research and Practice (2024).