Expert opinion: Mark Johnson is a San Diego-based journalist and author of Spitting in the Soup: Inside the Dirty Game of Doping in Sports. Here he lays out the associated risks of sports supplements

In the three years I spent researching my latest book, a theme repeatedly cropped up: for cyclists, using nutritional supplements and herbal medicines is a bad idea, and the products are hopelessly entangled with illegal performance-enhancing drug use.

Nutritional supplements are largely unregulated in Europe and the US. To put it more starkly, animal feed is more closely regulated than these human products.

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Many online-sourced products reach customers without having passed any verification for purity, safety or efficacy.

A 2015 analysis of supplements bought at major US retailers found that as many as five of six products did not include the ingredients on their labels, or contained substances not on the label at all.

Do you know what you're taking?

Do you know what you’re taking?

For a cyclist, using supplements with unknown contents is to play Russian roulette with your health.

Studies have shown that up to 60 per cent of supplements bought online are contaminated with substances not listed on the label.

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WADA’s own analysis revealed that the amount of illegal drugs spiking these pills and powders can be dangerously high.

We know that the majority of elite athletes take supplements, but the evidence suggests few of them appreciate the risks — and research has shown that those who take supplements are more likely to also used banned substances.


Recover with real food


Choosing to support the $30bn global supplements industry seems guided as much by emotion and faith as by rationality. A more sound use for your sterling is to hire a dietician.

Rather than burning money on mostly unproven pills and powders, you are better off making a scientifically grounded analysis of your current diet and nutrient, tweaking your meal plan accordingly — without the well-documented health risks and financial waste inherent to canned pills and powders.