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The 28-day tea-tox: Can trendy new herbal teas and powders really help you slim? 

It is a beguiling prospect: a tablet that can take all the hard work out of dieting, helping you slim down effortlessly, without having to feel a pang of hunger or break a sweat. Of course, no such thing has ever been invented.

But that hasn’t stopped a seemingly endless stream of health products being launched which, to greater or lesser extents, seem to promise just that.

The motivation? Well, 55 per cent of British adults attempted to lose weight last year. And it’s no surprise that the diet industry that has grown around this desire to shape up is worth a staggering £2 billion in the UK alone.

These days, high street chemist shelves heave with products promising to curb the appetite, boost natural calorie-burning and help us achieve the body of our dreams.

The motivation? Well, 55 per cent of British adults attempted to lose weight last year. And it’s no surprise that the diet industry that has grown around this desire to shape up is worth a staggering £2 billion in the UK alone

Many are marketed online directly to younger consumers with names like Flat Tummy Tea, Skinny Sprinkles and Boom Bod.

Others promise to contain ‘all natural’ ingredients said to boost heart health and protect against illness, such as green tea, herbs and fibre. A month’s supply of these concoctions can cost anywhere from £30 to £60.

The dark side of taking these supplements was thrown into sharp relief in October with the story of Jim McCants, a 50-year-old father-of-two who was left in need of a liver transplant after taking concentrated green tea capsules in a drive to get healthy in middle age.

Indeed, there have been at least 80 cases of liver injury linked to green tea supplements reported worldwide – including 17-year-old Madeline Papineau, from Canada, who developed liver and kidney injury, and an 81-year-old woman diagnosed with toxic acute hepatitis.

So what actually is in the latest slimming teas, pills and powders? And do they work – or could they actually be harmful?

We asked leading dietician Dr Sophie Claessens to look into some of the top brands…


Bootea 28-Day Teatox (£37.99,, Ideal Health Slimatee with Green Tea (£2.89, 10 bags,

Key ingredient

Green tea or oolong tea


Green tea (which comes from the same plant as black tea, but is raw rather than fermented so contains more antioxidants) is said to boost your metabolism so you burn more calories, helping you lose weight.

Oolong tea comes from the same tea plant as green tea, and is thought to have similar calorie-burning benefits.


Several studies have shown green tea can boost metabolic rate. This effect is thought to be due to a combination of the caffeine and catechins – antioxidants present in green tea, some fruits, dark chocolate and red wine. Dr Claessens says: ‘The effect is likely to lead to little, if any, change on the scales. You’d need to be drinking an awful lot to make any real difference.’

Even in large doses, the effect on weight loss is minimal. In a study published in 2016 in the journal Clinical Nutrition, overweight women having the equivalent of 15 cups of green tea a day lost less weight than those taking a placebo.


Experts have warned against large amounts of green tea in supplement form as there have been reports of serious liver damage. Drinking green tea itself doesn’t pose any serious health risks.


Skinny Mint 28-Day Ultimate Teatox (£39.90,, Flat Tummy Tea (£49 for four-week programme,




Tea containing ground leaves of the senna plant is said to reduce bloating, help cleanse or ‘detox’ the body and boost digestion.


This herbal supplement is classified by the NHS as a natural medication used to treat constipation. It stimulates your colon to contract more than normal, forcing out essential water and electrolytes (vital salts and minerals) along with faecal matter.

While this loss of bulk can make you feel and look a little slimmer in the short term, it has no impact on fat loss, because calories from food are absorbed in your small intestine long before it reaches the colon.

So any temporary slimming effect on your tummy is simply due to lost water weight and it will return to normal as soon as you replenish your fluids by drinking. ‘Plus the whole principle of detoxing has no scientific substance,’ explains Dr Claessens. ‘Your body doesn’t need help to detox – that’s what the liver and kidney do naturally and they’re very good at it.’


Dr Claessens says: ‘Senna isn’t regulated as it’s a herbal remedy, but it’s recommended that it should never be used for more than seven days. Yet many of these tea programmes are for at least 28 days.’

Taking senna can also be particularly irritating for those suffering from IBS – it could trigger stomach cramps and extreme diarrhoea.

Long-term, it is concerning if food passes too quickly through the body, as you won’t absorb many vital nutrients. The laxative effect of senna may also reduce the effectiveness of the contraceptive pill, with some reporting accidental pregnancies after using teas containing it. Laxatives can also be highly addictive, especially to young girls trying to lose weight.


Skinny Sprinkles (£39.98 for 60 servings,, Boombod 7 Day Achiever (£29.99 for 21 sachets,




Dubbed a ‘gastric band in a glass’, glucomannan is a type of fibre that absorbs water (water-soluble) and is derived from the roots of the konjac plant, often used as a food-thickener. A gel-like substance is created in the stomach, taking up space and making you feel full.

Glucomannan usually comes in powder form, to be added to water and taken before meals, up to three times a day.


Glucomannan is the only ingredient approved for contributing to weight loss by the EU Commission. ‘There is some decent evidence to show its effectiveness and if you’re someone who finds it easy to stop eating when you feel full, it could in theory help you,’ says Dr Claessens. ‘But if you’re the kind of person who can be tempted to keep eating despite feeling full, I doubt it will work.’

She adds: ‘Starting your meal with a bowl of healthy soup to fill you up would be just as effective, and an awful lot cheaper.’


‘We think so,’ advises Dr Claessens. ‘It’s not a quick fix but could be useful alongside eating fewer calories and exercising more.’