We do not need products to “detox” our bodies – our livers and kidneys have been doing that job just fine for millennia. Yet this doesn’t seem to be stopping some celebs cashing in on promoting “detox teas”, which are marketed as weight loss aids and usually aimed at women.

Actor Jameela Jamil recently called out Cardi B for promoting the brand Teami and Khloe Kardashian for posting a paid partnership with Fat Tummy Co. In a tweet, Jamil said: “If you tell your fans to be thinner, you don’t love your fans. You don’t give a shit about them or their mental health or self worth.”

To find out what detox teas really do to our bodies, HuffPost UK spoke to an NHS dietician and a registered nutritionist. Spoiler: it’s not pretty.

Chloe Hall, a community dietician at Dorset Healthcare University NHS foundation trust, said detox teas do “very little if you’re lucky” and may leave you “running to the bathroom if you’re not”.

“The ingredients in most of them are herbs and there is no evidence that they will help you lose weight,” she says. “Some of the products contain caffeine and if taken in excessive quantities caffeine can leave people feeling anxious, shaky and with heart palpitations.”

Some detox teas contain an ingredient called senna, which is more problematic. Both Flat Tummy Co and Teami sell products containing the ingredients. The plant extract acts as a laxative, according to Laura Thomas PhD, a nutritionist registered with the Association for Nutrition. 

“It’s only intended to be used in the short term, usually around one week, to help relive the symptoms of constipation,” she explained. “Many of these products are sold in courses of 28-days – far more than the one-week recommendation.”

Side effects of senna include stomach cramps and diarrhoea, particularly in those with irritable bowel syndrome, Thomas said. “Long-term diarrhoea can lead to dehydration which can be a risk for other health problems. Furthermore, prolonged use can lead to problems with the bowel working properly on its own,” she adds. 

Thomas said her main concern is the way in which some teas are marketed to influenceable young women “at higher risk of abusing laxatives, a symptom of disordered eating, by popular social media influencers”.

“Vulnerable people are also far more likely to take more than the recommended dose in a desperate attempt to control their weight and look like the social media influencers who are endorsing these products,” she said. “However, any weight lost with these types of products is just water weight and can lead to diarrhoea and dehydration.”

Focusing on weight as a predictor of health isn’t particularly helpful, said Thomas. “If you’d like to make positive health improvements, think about what you can add in to your diet, rather than take away, such as fibre from whole grains or fruits and vegetables, or heart healthy fats from oily fish,” she said.

“On top of that, making sure you’re getting enough sleep and moving your body for fun and enjoyment, rather than worrying about how many calories you’re burning.” 

[Read More: Jameela Jamil: Being Body-Shamed Showed Me We Need To Change Gym Culture]

Hall agreed that making small changes is the best way to achieve and maintain a healthy weight. “There is no one specific food that is going to help it is about the balance of your overall lifestyle which includes diet, activity, sleep and social aspects,” she said. “Reducing portion sizes gradually can help, as can finding an activity you enjoy.”