Do detox diets and juice cleanses actually flush toxins out of your body?

Your body already has a cleaning system, and it never pauses. The liver transforms substances so they can be excreted, the kidneys filter the blood, and the gut, skin and lungs all contribute. The system runs continuously, with no need to be restarted by a cleanse.

A critical review of the evidence, published in 2015 in the British Dietetic Association's journal, the Journal of Human Nutrition and Dietetics, examined whether detox diets are necessary, whether they work, and whether they carry risks. The conclusion: there is very little clinical evidence. The handful of studies that exist are small and methodologically flawed, and no randomised controlled trial has tested a commercial detox diet in humans. The market is growing faster than the evidence.

What a cleanse actually does shows up in a separate review (2017): a juice cleanse produces short-term weight loss, but only because it slashes calorie intake for a few days. The weight returns once normal eating resumes. The 'toxins' in the marketing are rarely named and never measured – there is no before-and-after test showing that anything left the body.

One thing to know: very long juice-only or fasting periods can leave you drained or dizzy. Feeling unwell on a cleanse is a reason to stop, not a sign that it is working.

The word 'toxin' borrows medical weight without pointing to anything measurable. Because it is never defined, the claim cannot be disproved – whatever you feel afterwards can be sold as the cleanse working. After a couple of days on juice you often feel lighter, but that is a calorie deficit and water, not flushed toxins. The brain ties the feeling to the product. And someone profits: cleanses, powders and detox programmes are sold by brands and influencers with affiliate links, in the same channels as every other wellness trend. A growing industry rests on a word that sounds clinical but never has to show a test result.

Your liver and kidneys already do this, for free and around the clock. A juice cleanse can produce short-term weight loss through a calorie deficit, but the weight usually returns once you go back to normal eating. If weight is the goal, a modest, sustainable deficit does the same thing without the rebound. Eat enough protein and fibre, and drink water. If a cleanse leaves you drained, dizzy or cold, stop. That is your body objecting, not toxins leaving.