They’re sold on Instagram with before-and-after photos and promises of a flat tummy in 14 days. This guide covers what’s actually in many slimming teas, why the weight comes back, and when using them is a sign of something more.
Many slimming and “flat tummy” teas work as laxatives, so the weight you lose is mostly water and stool, not fat, and it comes back. Frequent use can dehydrate you and lower your potassium, some products hide banned drugs, and using teas to control weight can be an eating-disorder warning sign.
What’s in them
Most slimming and detox teas rely on senna or similar plant laxatives, such as cascara, aloe or rhubarb root. In one US study of diet teas, 11 of the 12 contained senna. Some add caffeine or other stimulants, and the label doesn’t always match what’s inside.
The “detox” claim doesn’t hold up either. A review found no randomised trials of commercial detox diets in people, and there’s no evidence for the old idea that waste in your bowel slowly poisons you.
Why the weight comes back
Laxatives don’t stop your body absorbing calories. That’s why the UK’s NICE guideline tells clinicians to explain that laxatives don’t help with weight loss. In one small study, even extreme purging cut the calories absorbed by only about 12%. The quick drop on the scale is water and stool, and it returns when you stop.
Risks to your body
- Dehydration and low potassium. Using laxatives often or for a long time can cause dehydration and low potassium, which can bring muscle weakness, tiredness and heart rhythm problems. The risk is higher if you also take water tablets, some heart medicines or steroids, or have liquorice.
- The contraceptive pill. Diarrhoea can stop the pill working. On the combined pill, if diarrhoea lasts more than 24 hours, use condoms until seven days after it stops. Severe, watery diarrhoea can also make the progestogen-only pill fail. Ask a pharmacist or doctor.
- Hidden drugs. This is the biggest danger. Regulators keep finding banned drugs in “herbal” slimming products, most often sibutramine, a diet drug withdrawn in the US and Europe in 2010 after a large trial found more heart attacks and strokes among people with heart disease or diabetes who took it. An antidepressant and phenolphthalein, a substance linked to cancer risk, have turned up too. The US Food and Drug Administration has issued over 200 warnings about weight-loss products and says they’re only a fraction of the problem.
- Liver injury. Concentrated green tea extract, not ordinary brewed green tea, has been linked to liver injury, and Europe’s food safety agency couldn’t name a safe amount of the extract.
- Your bowel. Long-term heavy use may harm the bowel, though the evidence is limited, and some people find they take more and more over time.
What a NAFDAC number does and doesn’t mean
Slimming teas aren’t unregulated in Nigeria. NAFDAC requires herbal products and supplements to be registered before they’re sold or advertised, and its advertising rules ban promoting a herbal product as a treatment for obesity.
But a NAFDAC listing for a herbal product means it passed basic safety tests, not that it works. Labels must say “These claims have not been evaluated by NAFDAC”. And numbers can be fake: in 2021, NAFDAC warned that CHARMS Slimming & Tummy Reduction Tea wasn’t registered and carried a fake NAFDAC number. NAFDAC has also warned about slimming products containing sibutramine, some sold through Instagram.
So “NAFDAC approved” in an Instagram post doesn’t mean a tea melts fat. You can check a herbal product’s number in NAFDAC’s online herbal products database.
When it’s more than a diet
Using laxatives or diet pills to control weight is a recognised form of purging, and it can be an early warning sign of an eating disorder. In a large US study of young women, those who used laxatives to control their weight had about six times the odds of being diagnosed with an eating disorder within one to three years. That’s a link, not proof that the teas cause it.
The World Health Organization notes that herbal teas used as purgatives can be explained away as health remedies, which hides what’s really going on. “It’s just a detox” can cover a lot.
Suggested read: Binge Eating Disorder: Signs and Help
It may be more than a diet if you:
- take a tea or laxatives after eating to “undo” it
- feel panicky when you can’t take them
- need more and more over time
- hide how much you use
- let the scale decide your mood for the day
Body pressure is real. In a 2019 survey of students at two Lagos universities, about 6 in 10 were unhappy with their body image. Among those trying to manage their weight, more than a third used herbal mixtures and about 1 in 5 used laxatives. Interestingly, more students wanted to be heavier than thinner. Our piece on eating disorders in Nigeria looks at how pressure from both directions plays out.
If you want to stop
If you’ve been using laxative teas heavily, talk to a doctor before you stop. NICE advises cutting down gradually. After heavy use, bloating, swelling and constipation can happen for a while once you stop, and a doctor can check your salts and support you through it. Temporary bloating isn’t fat, and it isn’t a reason to go back.
If you want to lose weight, a doctor or dietitian can help you find a safer approach. Be wary of anything that promises fast results.
Getting help
If teas, laxatives or dieting have started to take over, you can find a therapist who works with eating disorders and body image by video, voice or chat. Read about recognising an eating disorder and body dysmorphia, see our eating disorders page, or look up bulimia nervosa in our glossary.
Frequently asked questions
Do slimming teas really work?
They can make the scale drop quickly, but most of that is water and stool from the laxative effect, and it comes back. Laxatives don’t stop your body absorbing calories.
Are slimming teas safe?
Not for regular use. Frequent use can cause dehydration and low potassium, some products contain hidden banned drugs, and diarrhoea can stop the contraceptive pill working.
Does a NAFDAC number mean a tea is safe and works?
No. A listing means a herbal product passed basic safety checks, not that its claims are true, and fake numbers have been found. Check the number in NAFDAC’s database.
Can slimming tea affect my birth control pill?
Yes, if it gives you diarrhoea. On the combined pill, diarrhoea for more than 24 hours means using condoms until seven days after it stops. Ask a pharmacist or doctor.
Is using slimming teas a sign of an eating disorder?
Not on its own. But using teas or laxatives to make up for eating, or feeling unable to stop, can be a warning sign and is worth talking to someone about.
Suggested read: Losing a Spouse: Grief and What Comes After
This article is awaiting clinical review. It’s based on published research and health guidelines, and we’ll update it once a clinician has reviewed it.
