Van Tulleken challenges 1,000% collagen markups in wellness book

Xand van Tulleken’s Make Me Well challenges wellness products including collagen sold at markups of as much as 1,000% in today’s market, according to a Guardian book review published Oct. 16, 2026.

Markup means the increase over cost. At 1,000%, it equals 10 times the base cost added to the price, according to Atlas360 calculations; the review contrasts that market with NHS advice to consider a daily vitamin D dose during autumn and winter.

The book, as described by the review, focuses on the evidence behind wellness products that are sold through shops, social media and private health services. It covers vitamin D, collagen, testosterone, multivitamins, turmeric, krill oil, personalised nutrition, glucose monitoring, wearable technology and private blood screening.

Van Tulleken qualified during a period of strong interest in vitamin D research, the review says. In the early 2000s, large studies were associating the vitamin with outcomes beyond bones, including cancer, heart disease and dementia.

“The range of potential problems to be solved was dizzying,” Van Tulleken writes in Make Me Well, according to the review.

The Guardian review says Van Tulleken examined decades of trials and spoke to a professor who had spent a career on vitamin D. The reviewer says he finds no justification for routine use except among people who are genuinely deficient.

That conclusion is significant because vitamin D is presented in the review as one of the more medically accepted supplements. The NHS advice cited by the review says people should consider taking it during autumn and winter, when sunlight exposure is lower and deficiency risk rises.

The collagen chapter broadens the book’s argument from clinical evidence to supply chains and marketing. The review says Van Tulleken travelled to China while examining ejiao, a donkey-derived collagen product sold as a premium beauty supplement.

According to the review, demand for donkey hides exhausted Chinese supplies and drew in animals from rural communities in African countries. The review links that trade to the wider sale of gummies, powders and other products made from animal-derived collagen.

Van Tulleken also examines the business systems around supplements, the review says, including podcasts, influencers and scientific publishing. “The more research I do, the more I see the same patterns repeatedly: conflicts of interest, industry-funded trials, industry-owned journals and an entire system designed to exploit people,” he writes, according to the review.

The review does not include responses from supplement companies, makers of wearable devices or private screening providers. Its account of the evidence base is presented through the reviewer’s reading of Van Tulleken’s reporting and conclusions.

Van Tulleken’s conclusion, as quoted in the review, is that health for generally healthy people may depend more on habits and communities than purchasable products. “The right people to make you well won’t be health gurus,” he says. “They might be dance instructors or librarians or martial arts teachers or the person who runs your local choir.”