Swissmedic warns: Illegal "Slimming preparations" and "detox products" can make you ill (2025)

Slimming preparations and detox products advertised as "wonder drugs" in dubious online shops or on social media can contain undeclared pharmaceutical substances. Among the active substances regularly found by Swissmedic's laboratory when it analyses such preparations is sibutramine, which is harmful to health. Sibutramine was marketed under the brand name Reductil® in Europe and Switzerland until 2010, when it was withdrawn from the market because the risks outweighed the benefits. Products sold illegally on the Internet often contain significantly more sibutramine than the authorised prescription-only medicines used to contain, and the associated health risk is correspondingly high. Swissmedic repeatedly receives reports of undesirable effects such as a racing heart, nausea or dryness of the mouth from people who have taken these products.

The Agency has noticed that illegal imports of allegedly "completely natural" weight reduction or "detox" products have recently started to rise again. The products are mostly sold as herbal teas, "natural" capsules or instant drinks. Social media such as Instagram and Facebook are particularly popular channels for advertising and selling such products. However, "completely herbal wonder drugs" to help people lose weight or detox may contain undeclared pharmaceutical substances.

Samples of slimming teas examined after consumers reported side effects such as abnormal heart rhythms after using them were found to contain large quantities of sibutramine. Medicinal products containing this active substance have not been on the market worldwide since 2010 because of the elevated risk of cardiovascular disease.

In summer 2024, an imported preparation named "MAX Slim 7 Days", which contained approximately 103 mg of sibutramine per capsule, was confiscated. The sibutramine content is seven times greater – and therefore significantly higher – than the maximum daily dose formerly authorised in the medicinal products. The packaging makes no mention of pharmaceutically active substances and the content of the now banned active substance is not disclosed.

This is a huge risk because consumers believe themselves to be safe, since the description on the packaging says the product is "completely herbal". The impact on health can be serious. Taking preparations of this kind can significantly increase both blood pressure and heart rate. Other undesirable effects include dryness of the mouth, headaches and constipation. Swissmedic therefore urges consumers not to take such "wonder slimming aids".