Fat Burning Herbs: What the Evidence Really Says

Search for fat burning herbs and you will find long lists: green tea, chili, garcinia, bitter orange, forskolin and more. Many are sold as capsules or powders with words like thermogenic or metabolism boosting on the label.

A tea or capsule sounds simpler than changing habits, so it is worth looking fairly at what these herbs are claimed to do, what research has actually found, and where the real risks are.

What the claims say

The usual promise is that certain plants make your body burn more calories, break down stored fat, block fat from being absorbed or curb your appetite. Green tea is said to speed up calorie burning. Chili is said to heat the body. Garcinia and bitter orange are often packaged with caffeine and sold as fat burners.

Some of these ideas start from a grain of truth. Caffeine, for example, is a real stimulant found in tea, guarana, kola nut and yerba mate. The question is whether the effect is big enough to matter, and whether the products are safe.

What the evidence says

The NIH Office of Dietary Supplements says there is little scientific evidence that weight-loss supplements work. Most ingredients have only been tested in small, short studies, and many products mix several ingredients whose combined effects are unknown.

Green tea. NCCIH says the catechins and caffeine in green tea may have a modest effect on body weight, and results vary. Drinking green tea is considered safe for adults, but liver injury has been reported in some people who used green tea extracts.

Caffeine. Supplements with caffeine may lead to a small weight loss or less weight gain over time, but your body gets used to it, so the effect may fade.

Chili (capsaicin). It has not been studied enough to know whether it helps with weight loss.

Garcinia cambogia. Studies show little to no effect on weight.

Bitter orange. Whether it helps with weight loss is unknown, and it might not be safe. It can raise heart rate and blood pressure and has been linked to chest pain and anxiety.

Forskolin, hoodia and yohimbe. The ODS says forskolin has not been found to affect body weight, hoodia probably does not help, and yohimbe does not help and may be unsafe. In short, no herb has been shown to be a reliable fat burner. At best, a few ingredients show small effects in short studies.

The hidden danger in fat burner products

The FDA does not review supplements for safety or effectiveness before they go on sale. FDA lab tests have found prescription drugs hidden in weight-loss products sold over the counter, including some with herbal in their names.

Many of the products contained sibutramine, a drug withdrawn from the US market in 2010 because of a higher risk of heart attack and stroke. Others contained phenolphthalein, a former laxative ingredient linked to cancer risk, and the prescription diuretics furosemide and bumetanide, which can cause severe dehydration. The FDA warns that words like thermogenesis, secret ingredient or safe because it is natural are signs of health fraud.

What actually helps

The NHS suggests aiming to lose about 0.5 to 1 kg (1 to 2 pounds) a week, and not losing weight suddenly with crash diets. Swap sugary drinks for water, try not to skip meals, since that can lead to more snacking later, and build up to about 150 minutes of activity a week, which you can split into short sessions.

This is where a herb can play a small, honest role. A jug of unsweetened iced herbal tea in the fridge makes it easier to choose it over a sweet soft drink.

Questions people ask

This article is for general information only and is not medical advice. Herbs can interact with medicines and health conditions. Talk to a doctor or pharmacist before trying a herbal remedy, especially if you are pregnant, breastfeeding, giving it to a child, or taking any medication.