On this page
A bottle of “detox water”, a three-day juice cleanse, a herbal tea that promises to flush you out: the claim is always that something is building up inside you and the drink will remove it. Here is what your body already does with waste, and what the research found.
Do detox drinks work, according to research?
A critical review of the evidence by A. V. Klein and H. Kiat appeared in the Journal of Human Nutrition and Dietetics (online in 2014, in print in 2015). Their abstract says it plainly: “Although the detox industry is booming, there is very little clinical evidence to support the use of these diets.” To the best of their knowledge, no randomised controlled trials had tested commercial detox diets in people. The few clinical studies reporting that these diets boosted liver detoxification had flawed methods and small samples.
The US National Center for Complementary and Integrative Health (NCCIH) reaches the same view in its fact sheet on detoxes and cleanses. The few studies in people have been of low quality, and there have been no studies on the long-term effects of detox programmes.
What do the liver and kidneys already do?
Biotransformation is a metabolic process that takes place mainly in the liver and helps the body excrete substances, both those it makes and those it takes in (StatPearls, via Europe PMC). Cleveland Clinic describes the liver breaking down toxins so they leave the body in urine and stool, with bile ducts carrying bile from the liver to the small intestine.
The kidneys do the filtering. According to the US National Institute of Diabetes and Digestive and Kidney Diseases, each kidney has about a million filtering units called nephrons. Together they filter about 150 quarts of blood a day, and only 1 to 2 quarts become urine. They remove wastes, extra fluid and the acid your cells produce.
How much of what the kidneys filter becomes urine?
Use the NIDDK figures and one conversion: 1 quart is about 0.95 litres.
Filtered each day: about 150 quarts, roughly 142 litres.
Leaves as urine: 1 to 2 quarts, roughly 1 to 2 litres.
Take the middle value: 1.5 ÷ 150 = 0.01, so about 1 percent leaves.
The other 99 percent: NIDDK says the tubules return most of it to the blood.
So the kidney is not a drain you need to flush. It is a sorting machine that keeps what the body needs and lets waste go. A glass of lemon or jeera water adds to the fluid it handles, but the review found no randomised trial showing that commercial detox diets do more than that.
Do detox drinks help you lose weight?
According to NCCIH, a 2017 review found that juicing and detox diets can cause initial weight loss because you take in fewer calories, but they tend to lead to weight gain once a person goes back to a normal diet. Any lighter feeling during a cleanse is not a measurement. Our explainer on the placebo effect, blinding and trials shows why a study needs a control group before a feeling counts as evidence.
Can a detox cleanse be harmful?
It can. The NCCIH fact sheet lists several risks:
Juices made from high-oxalate foods such as leafy greens and beets can be a health threat to people prone to kidney stones.
Unpasteurised juice can make people sick, seriously so in children, older people and those with weakened immune systems.
Some programmes include laxatives, which can cause diarrhoea and lead to dehydration.
Drinking large amounts of water and herbal tea while eating nothing for days could lead to dangerous electrolyte imbalances.
The US FDA and FTC have acted against several companies selling detox products that contained hidden ingredients.
The same fact sheet tells people with diabetes to talk to their health care team before making major changes to what they eat.
How can you check a detox claim yourself?
Run any detox label through these five questions.
Which toxin? A real claim names a chemical. “Toxins” alone cannot be tested.
Measured how? It should show the level in blood or urine before and after.
Compared with what? It needs a control group, ideally randomised. The review above found no such trial for commercial detox diets.
What is actually in it? Read the back of the pack, especially sugar per serving; here is how to read a nutrition label in India.
Who gains if you believe it? The seller does, whether or not the drink works.
This is the same check we ran on alkaline water and stomach chemistry: start from what the body already does, then ask what the product adds.
If nephrons and excretion still feel hazy from Class 11 biology, the Fermi Concept Library has every concept in biology with its own lesson and its place in the map.
Next time a bottle says detox, ask the five questions and remember the 1 percent: your kidneys are already doing the work.
