Nutrition Notes

Collagen: A Clinical Look at Hair and Skin Health

The skin is composed of three layers: epidermis, dermis, and hypodermis. The dermis is the largest of the three skin layers and contains a high amount of collagen. During the aging process or exposure to certain environmental factors including UV light, the skin’s collagen structure may degrade or accumulate abnormally. This may also involve reduced elasticity, deterioration of fibroblast number or function, dermal thinning, and decreases in collagen production. Changes in the hydration of the epidermis and increased vulnerability to damage may also occur.

In laboratory and animal studies, collagen has been shown to influence several proteins related to skin and cellular health. These include IGF-1, VEGF, krt27, Gprc5d, and Ki67. Collagen has also been shown to upregulate Wnt/β-catenin pathways, which are involved in hair follicle cell differentiation, reproduction, and the differentiation of stem cells into hair follicles. Collagen and its fragments have also been shown to induce the differentiation of regulatory T cells and M2 macrophages that contribute to increased skin turnover and healthy tissue remodeling

A randomized clinical trial reported improvements in collagen fiber appearance and significant improvements in parameters related to photoaging (the echogenicity of the dermis) in individuals receiving 500 mg of hydrolyzed collagen daily for 3 months. An 8-week clinical study involving 50 participants reported improvements in certain parameters related to skin hydration, brightness, and eye wrinkles. 

A systematic review and meta-analysis by Pu and colleagues amalgamated data from 26 randomized controlled trials involving over 1700 individuals to investigate the efficacy of hydrolyzed collagen supplementation. The studies lasted between 2 and 12 weeks. Overall, the authors reported significant improvements in skin hydration and elasticity when compared to placebo. Improvements were found to depend on the duration of supplementation and the source of collagen. Bovine-sourced collagen was among those with better outcomes; collagen sourced from chicken was the least efficacious. An animal study exploring the effect of bovine-sourced collagen peptides in aged mice reported increases in skin collagen content and improvements in skin laxity and the ratio of type I to type III collagen. 

Supplementation with collagen may also help support certain aspects of musculoskeletal health. A randomized, double-blind clinical trial explored the potential efficacy of supplementation with collagen peptides in postmenopausal women. The treatment group received 5 g of collagen daily for 48 weeks. Improvements in certain markers related to bone integrity and formation were noted. Several other clinical studies, conducted in both young and elderly adults, have reported improvements in muscle strength, muscle mass, and proteins related to contractile fibers.

While more research is needed, particularly in the clinical setting, evidence suggests that collagen may help support healthy aging. It may also help promote skin, hair, and musculoskeletal health. Dietary sources of collagen include bone broth, gelatin, and certain meats.

By Dr. Cory Ambrose, ND, MAT