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Over 28% of dietary supplements contain undisclosed & banned substances - Research Spotlight

Updated: Apr 10

Sports supplements, protein powder, neil livemore sports nutrition
Are you confident the supplements you consume are low risk for undisclosed substances?

A recent study has found that over 28% of dietary supplements contain undisclosed substances. Some of the most frequently found undeclared substances are sibutramine and anabolic steroids.

Research paper, sports supplements, dietary supplements
A recent paper found a large percentage of supplements had undisclosed substances.

While this may seem shocking, it is nothing new to sports nutritionists but does highlight the importance of supplement safety to the general population and athletes whos careers (and health) may be at risk.

Undeclared substances pose a risk of inadvertent doping and being banned from their sport for athletes.

For the person, it can pose a health concern.

For the athlete, it can mean a ban from the sport, competing and facilities/activities associated with the sport for a period of time.

However, I think everyone can agree that we want to know that what we are consuming, is what's on the label from a health perspective.

Why does this happen?

The quality, identity and purity of the products are not regulated. Manufacturers are not required to provide information about safety before introducing supplements on the market – they are free to establish their own practice guidelines. This can often mean dietary supplements are adulterated and contaminated or fail to contain claimed active ingredients.

Studies have found that many supplements contain undeclared compounds like prohormones or anabolic androgenic steroids (AAS).

In a study where 634 dietary supplements from 15 different countries (Geyer and team 2004), 14.8% of supplements showed anabolic steroids concentrations from up to 190 μg/g.

Baume et al. analysed the purity of supplements from different websites: 103 dietary supplements, including stimulants, amino acids, creatine, and others. They found 18% of the analysed dietary supplements contained undeclared steroids or their precursors.

Although supplements are associated with health, they can have negative outcomes – in the USA 23,000 emergency visits are due to dietary supplement-related adverse events.

So, what can we do?

A food-first approach is always recommended, although often it is a “food first, but not always food only” approach.

Many supplements are not beneficial despite marketing and online claims but there are some supplements that may work for:

  • A specific population.

  • At a specific time

  • For a specific goal

  • When it may be tricky to get from food.

1) Use a simple safe supplementation flow chart to make decisions.

Neil Livemore supplemnts in sports nutrition flow chart
SENr Safe Supplement Decision Flowchart

2) Use batch tested supplements to reduce risk of banned/undisclosed supplements (and log the batch numbers if you are an athlete).

  • In the UK this will be Informed Sport tested supplements (that include the informed sport logo). Their website ( also has tested supplements added to their register.

  • In the USA, it is NSF certified for sport.

Informed Sport Batch Test Supplements

3) Use a qualified SENr sports nutritionist or sports dietician who can help advise on the use of supplements for your specific needs, which can be achieved through foods and which supplements are flushing your money down the drain.

4) Complete a free online course available from UK anti-doping to help educate on clean sport and safe supplementation.

Have more questions? You can contact us on our form below!



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