Supplements: benefits and risks

Joëlle Flück 16. October 2019

New supplements or food supplements appear on the already huge market each year. This makes it immensely difficult to maintain an overview or even assess the evidence-based supplements. Here you will find the necessary explanations.

Presented by Swiss Sports Nutrition Society

Supplements should be used prudently and sensibly. It is best to discuss this with a specialist and tailor them to your individual needs, because supplements are meant to enhance and not replace your basic diet.

Supplements are generally classified in four different categories: A, B, C and D supplements. The classification takes into account the supplements’ ingredients, their mechanisms of action, and their impact on health and athletic performance. Using supplements that are supported by evidence-based literature and can thus positively affect performance or recovery in specific situations is recommended.

“A supplements” are those supplements that are perfectly legitimate in certain sports situations and are supported by good scientific evidence. While the use of “B supplements” can make absolute sense, the scientific evidence is not yet sufficiently available. “C supplements” are considered to be of little or no use in sports, which is why their use is not recommended. The “D supplements” category ultimately contains all those supplements whose use in sports is prohibited by the World Anti-Doping Agency (WADA) or those which have a very high risk of being contaminated with prohibited substances.

A supplements – the most effective food supplements

This category contains the most well-known sports foods such as sports drinks, gels, energy bars, meal replacement products as well as regeneration products. It has been clearly demonstrated in the past that using them during the load can sustain the performance for longer or even improve it. 

Medical supplements such as probiotics, iron supplements, calcium, vitamin D and multi-vitamin preparations can also be used by athletes. Especially when there are symptoms of a deficiency or if the athlete needs to cure an acute gastrointestinal disease.

Other supplements in this category are described as performance supplements and in certain sports with specific requirements profiles (e.g. load duration and intensity, production of lactic acid or the athletes’ ability to concentrate) show an improvement in performance when compared to a placebo. These supplements are namely beta-alanine, bicarbonate, caffeine and creatine.


B supplements – not enough evidence (yet?)

In this group, several supplements are classified that could potentially be used in sports but have not (yet?) been sufficiently and meaningfully tested. They should therefore only be used and monitored under the direction of a specialist. The current B supplements are carnitine, glucosamine, HMB and beetroot juice.

C and D supplements – use is undesirable

The C and D supplements should be avoided. Not only because there is no given scientific evidence, but also because they have an increased risk of being contaminated with prohibited substances. Take colostrum, for example. While it is not generally prohibited in sports, it is unclear whether its ingredients could trigger a positive doping test for prohibited substances. The supplements in these categories are taboo for all athletes!


Any ingestion of an artificially produced supplement ultimately entails the risk that it has been contaminated with prohibited substances during the manufacturing process. The risk is greater with supplements that can be ordered via the Internet, as there is usually no evidence of the quality of production. All the more reason for avoiding such supplements at all costs.

The risk can be significantly reduced if the supplements are not ordered online, there is evidence of the manufacturing process and quality, or if you use Swiss products from one of the largest Swiss sports nutrition companies, who get their products tested for contamination. 


In general, it is recommended that any supplementation, whether it is medically or athletically indicated, is discussed with a sports nutrition specialist. In addition, the supplementation should be tailored to the requirements profiles of the sport, so that the supplementation can be carried out effectively. Supplementation for adolescent athletes or athletes who have not yet realised their full potential through training stimuli is generally not recommended. Individual support and advice is ultimately the be-all and end-all when it comes to any kind of supplementation.