Nearly 40% of weight loss products marketed as “natural” contain banned substances, according to a fresh study, raising concerns about potential health risks for consumers.
The findings highlight the dangers of assuming herbal weight loss aids are automatically harmless. A recent scientific evaluation revealed that around one-third of purportedly natural slimming products worldwide are contaminated with synthetic drugs – often including dangerous substances like sibutramine, an appetite suppressant banned in Europe for years.
Dangerous Combination: Marketed as Natural, Artificially Enhanced
The investigation analyzed 26 laboratory studies that examined herbal preparations, teas, and capsules for undeclared additives.
The results showed that nearly 40% of the tested products contained pharmacologically active ingredients that shouldn’t be present. Products purchased from local markets and online shops were more frequently found to be adulterated, while those from pharmacies were less often affected.
Manufacturers often mix prohibited appetite suppressants, stimulants, or diuretics into their products to achieve a rapid effect. This can have serious consequences for consumers, ranging from a racing heart and high blood pressure to severe circulatory problems.
The Rise of “Natural” Solutions
The World Health Organization now recognizes obesity as one of the biggest global health threats. This has created a massive market for herbal remedies, teas, and dietary supplements promising a “natural” solution to weight problems. Many people turn to these options hoping for a gentle way to support their bodies.
Though, the analysis suggests that traditional knowledge is often misused. Plants like Garcinia, turmeric, and green tea historically played a role in ancient medical systems – but as part of holistic therapies, not as quick-fix miracle cures. Today, they are often sold in powder, capsule, or drink form, losing the original context.
High Levels of Contamination in Europe and the Middle East
In laboratory analyses, researchers found substances such as phenolphthalein, a laxative, and ephedrine, a stimulant, in addition to sibutramine. Some products contained multiple drugs simultaneously, sometimes in high doses. The proportion of contamination was particularly high in Europe and the Middle East, where over half of the tested products were affected in some samples.
Lack of Oversight, High Risk
A significant issue is that many of these products are marketed as dietary supplements rather than medications. This means they are subject to less stringent regulations and can easily reach the market. Those purchasing online should always look for appropriate laboratory certificates, which reputable shops readily provide.
Researchers are calling for stricter controls, international collaboration, and better public education. Only through common standards can it be prevented that consumers unknowingly ingest medications through “natural” slimming products.
What You Can Do
- Purchase weight loss products only from pharmacies or trusted shops that also provide laboratory certificates, such as nutrient and contaminant analyses.
- Be skeptical of “fast-acting” claims – these are often warning signs.
- Learn about ingredients and consult a doctor before taking dietary supplements.
- If you experience unexpected side effects, stop taking the product immediately and seek medical advice.
Conclusion
The current study clearly demonstrates that “natural” doesn’t always mean natural. Approximately one-third of tested weight loss teas or slimming capsules contained banned drugs – a serious risk to health. Those seeking to lose weight should focus on proven methods: a balanced diet, exercise, and medically supervised treatments.
Prof. Dr. Klaus Günther, a food scientist and biochemist, conducts research and teaches at the University of Bonn on micronutrients and innovative nutritional research and serves internationally as an honorary professor, and reviewer. He is part of our EXPERTS Circle. The content represents his personal opinion based on his individual expertise.
