All around the world, more and more people are taking dietary supplements that promise better skin and hair, a strengthened immune system or improved performance. Magnesium, vitamin C and others are part of a market worth billions of euros.

Angela Clausen from the consumer advice center in North Rhine-Westphalia has been dealing with this topic for years.

"The problem is that a great many people see dietary supplements as a kind of natural medication, so they use them accordingly: for therapy, and to relieve or heal diseases," she said. "But dietary supplements are only really intended to supplement essential components that we don't get enough of from our diet."

In the best-case scenario, when consumers buy dietary supplements that don't offer any benefits, they're just wasting their money. However, some substances, such as vitamin D, iodine or selenium can be harmful if too much is consumed.

Food supplements are also subject to far fewer controls, precisely because they are not medications. They can be marketed without having been tested for safety, quality, or effectiveness. Consequently, dietary supplements don't always contain the ingredients indicated on the packet, or may not do so in the quantities stated. Sometimes they even contain substances that are dangerous or banned.

On social media, there is even less monitoring of these claims. False promises about the healthy properties of dietary supplements are found everywhere, as demonstrated by a random investigation of hundreds of posts and stories conducted in 2021.

DW Fact Check did its own search for claims about dietary supplements on social media, then took three examples and analyzed them.

Supplements to make you smarter?

Claim: In this TikTok video, which has been viewed around 1.7 million times, a user claims: "You're not stupid, you just don't have enough circulation going to your brain, which is preventing you from focusing, concentrating effectively and it's leading to really poor memory."

Her top four recommended supplements to help with this are ginkgo biloba, bacopa monnieri, L-theanine and magnesium L-threonate.

DW fact check: False

Better cognitive performance and concentration thanks to these dietary supplements — unfortunately, it's too good to be true. Nutritionist Friederike Schmidt from the University of Lübeck analyzed the video for DW.

"The TikToker talks about very specific metabolic mechanisms, and she does initially appear competent," said Schmidt. However, she pointed out that, with regard to many aspects of the preparations the woman mentions, "we actually have no idea what they do and whether they help at all."

For example, one of the claims made in the video is that the plant extract bacopa monnieri raises the level of the neurotransmitter acetylcholine in the brain, which improves memory.

"This is very far-fetched," said Schmidt. "As yet, there has been not one methodologically sound study, let alone several, in which people have been given this plant extract, had more acetylcholine in their brains, and were then better able to remember things."

Angela Clausen from the consumer advice center knows all too well that citing studies of little or no relevance or significance is a common tactic when advertising dietary supplements. "The studies presented are usually a disaster as far as the actual product is concerned," she said.

Overall, the TikToker's claims are not at all scientifically sound. There is no proof that her "top four supplement recommendations" improve cognitive performance in the way she describes.

Turmeric: A miracle cure?

Claim: According to this Spanish-language video, which has had more than 1.5 million views, powdered turmeric dissolved in water can help against eczema. It is also alleged to detoxify the body, prevent arthritis and reduce the risk of cancer. Similar claims can be found here and here, as well as elsewhere.

DW fact check: False

Used as a spice, turmeric has long been held to be good for the digestion. However, according to Clausen, "all these claims are inadmissible; there are no existing studies to support them."

There has indeed been research done into the active ingredient in turmeric, curcumin — but there are no "gold standard studies" relating to the imprecisely defined extracts used in the products. This would mean studies conducted in humans, in which neither the researchers nor the subjects knew who had received the placebo and who the active ingredient, and which have ideally been corroborated by at least one other study conducted by a different working group.

Studies have only shown that a specific turmeric extract, at a specific dosage, has an anti-inflammatory effect in laboratory tests, in a test tube. But these effects can only be attributed to precisely this extract, in precisely this dosage, not simply to turmeric. The effect in humans can be completely different to the effect in a test tube.

"We are very far from being able to say that turmeric definitely helps," said Schmidt. The nutritionist explained that a particular problem with curcumin is that it is very reactive, meaning that in the laboratory it interacts with many other substances — which is presumably also why it is said to be effective against so many different diseases and problems. But this doesn't necessarily mean it will be effective in people.

Better skin, hair, nails and joints with collagen?

Claim: Posts on social media also ascribe many positive attributes to collagen. This viral video claims it will give you firmer skin, stronger nails and shinier, stronger hair, while this TikTok clip asserts that it will also support your joints.

DW fact check: False

Collagen is a protein naturally produced by the body, and it's important for bones, joints, muscles and tendons. Dietary supplements containing collagen are therefore derived from animals, usually slaughterhouse waste.

It's not clear how well the body is able to process collagen received from external sources. Even the best-known supposed effect of collagen — a rejuvenating effect on the skin — is still in need of further research, according to a meta-study conducted in 2023.

"None of these advertising promises are approved for use in the EU, certainly not the one about joint health," said consumer adviser Clausen. There is no conclusive evidence it has this effect, she added. The consumer advice center even successfully sued the manufacturer of Glow25 Collagen Powder in 2022 for using the slogan "Healthy bones and joints."

The suppliers acknowledged that their promises with regard to its effects on skin, hair and nails were inadmissible. Nonetheless, many posts online still make these claims.

Conclusion: Consumers are being misled

With dietary supplements, it's not easy to separate the truth from the hype. Generally speaking, the claims made on social media are often exaggerated, unscientific or have even been prohibited.

"In many cases, we see that people are just spending money on things they don't need," said Schmidt. She described it as "a very tempting idea: that you can do something for your health with a few capsules or powders."

Additional reporting by Julia Vergin.

This article was originally written in German.