Collagen supplements have surged in popularity worldwide, with consumers spending an estimated £2 billion annually on products claiming to improve skin, hair, nails, and joint health. However, a new book by doctor and broadcaster Xand van Tulleken raises questions about the effectiveness of these supplements and the broader wellness industry.
Collagen is the most abundant protein in the human body, contributing to the strength and elasticity of skin, cartilage, joints, and ligaments. This biological role underpins claims that ingesting collagen supplements can revitalize these tissues. Yet, van Tulleken explains that the body does not absorb collagen in its whole protein form. Instead, digestive enzymes break down large protein molecules into amino acids, which are then reassembled by the body according to its needs.
This process differs from the absorption of vitamins and minerals, which are smaller molecules that can be more directly utilized by the body. Van Tulleken points out that therapeutic proteins, such as insulin or weight-loss drugs like Wegovy, must be injected because they cannot be absorbed intact through the digestive system. While pharmaceutical advances have produced oral forms of some protein-based drugs through chemical modifications, no such formulation exists for collagen supplements.
Evidence on the efficacy of collagen supplements is mixed. Several clinical trials have reported improvements in skin elasticity and reduced wrinkles among participants. However, a systematic review conducted last year scrutinized these studies based on methodological rigor and funding sources. The analysis found that industry-funded trials and those with lower quality standards tended to show positive outcomes. In contrast, independently funded and higher-quality trials generally failed to demonstrate significant benefits.
Van Tulleken characterized this pattern as indicative of industry bias, stating it is “unusual to see such clear evidence of industry manipulation.” However, some experts urge caution before dismissing all industry-sponsored research. Professor Lee Smith, a public health specialist at Anglia Ruskin University, emphasized that industry-funded trials undergo the same ethical and peer-review processes as other studies. He noted that excluding such research would result in the loss of a substantial portion of the evidence base that informs clinical practice.
As the market for collagen supplements continues to expand, consumers and healthcare professionals are advised to consider the current scientific debates and the varying quality of available research before relying on these products for health benefits.