General information, not medical advice. If you are considering a significant dietary change, or have kidney, liver or metabolic conditions, speak to a doctor or registered dietitian first.
Detox is one of the few health words that survives entirely on grammar. It is a verb with no object. You detox — but from what?
In 2009, a network of early-career scientists organised through Sense About Science decided to find out. They bought fifteen products marketed as detoxifying — foot pads, supplements, shampoo, bottled water, a hair straightener — rang the companies behind them, and asked two questions. What do you mean by detox? And which toxin does your product remove?
The answers
Their report, The Detox Dossier, records that not one company could give a comprehensive definition of what they meant by detox, and that no two companies used the same definition.
Where a substance was named at all, it turned out to be something ordinary. One cosmetics brand meant sebum, make-up and oil. A high-street detox brush meant dead skin cells. One supplement meant “basically free radicals.” Another meant fatty deposits. A detox shampoo meant dirt and grime.
Eleven of the fifteen were written up. Some companies dropped out of the exercise when asked to supply the evidence behind their claims.
The authors’ conclusion was blunt: detox, as used in product marketing, is a myth, and the word has no meaning outside the clinical treatment of poisoning and drug withdrawal.
The exception, and what happened to it
One detox marketer did name specific toxins — in detail — and it is instructive to see how that went.
Kinoki Foot Pads were sold on the claim that, applied overnight, they drew contaminants out through the soles of the feet. The Federal Trade Commission’s 2009 complaint against Xacta 3000 Inc. lists the substances the advertising claimed to remove: benzene, isopropyl alcohol, methyl alcohol, aluminium, cadmium, copper, lead, mercury, nickel, thallium, arsenic, asbestos, PCBs, along with heavy metals, parasites and metabolic wastes as categories.
The FTC charged that these claims, and the accompanying promises to treat headaches, depression, fatigue, diabetes, arthritis, high blood pressure and insomnia, were false or unsubstantiated when made.
So the one case where a company answered the question precisely is also the case where a regulator took it to federal court. A named toxin list turned out to be evidence of a bigger problem, not of a working product.
What the trials say
Alexandra Klein and Hosen Kiat reviewed the evidence on detox diets in the Journal of Human Nutrition and Dietetics in 2015. Their finding on commercial detox diets is one sentence and it has not changed since: to the best of their knowledge, no randomised controlled trial has ever been conducted to assess whether they work in humans.
That is a narrower statement than “detox diets have been disproved,” and the distinction matters. The experiment has not been run. A handful of small clinical studies have reported that certain regimens help eliminate persistent organic pollutants, and there is preliminary work on coriander, nori and olestra — mostly in animals. Klein and Kiat describe this literature as methodologically flawed and small-sample. It is a thin signal, not a result.
Colon cleansing has been looked at more directly. Ruben Acosta and Brooks Cash reviewed it in the American Journal of Gastroenterology in 2009 and found no methodologically rigorous controlled trials supporting it for general health promotion — alongside multiple case reports of adverse effects. Their conclusion was that it cannot be recommended.
What the regulators have decided
Britain’s Advertising Standards Authority has ruled on this repeatedly, and the rulings are a useful record because they turn on evidence rather than opinion.
In 2014 the ASA upheld complaints against all ten health claims made for a detox tea, including “cleanse and detoxify,” “increase your metabolism” and “burn fat and counteract fat storage.” In 2015 it upheld against a juice company’s “detoxifier” and “blood purifier.” In 2018 it upheld against Pukka Herbs, rejecting the argument that “detox” functioned as a brand name rather than a health claim.
The Committee of Advertising Practice states its position plainly in its guidance: it has not seen evidence to support the theory that toxins can be removed from the body by means other than the liver and kidneys.
The FTC’s record runs in parallel. In 2008 it obtained a $14.4 million judgment, suspended for inability to pay, against the marketers of a herbal colon-cleansing programme that claimed to cure cancer, AIDS, Alzheimer’s and diabetes. In 2020 it brought an action over a “30 Day Detox Pack,” resulting in a $15.2 million judgment suspended on payment of $1 million — of which more than $930,000 was eventually returned to consumers.
The system that already does this
The reason none of this works is that the job is taken.
The liver handles foreign compounds in two stages. Phase I reactions — oxidation, reduction, hydrolysis, largely via cytochrome P450 enzymes — convert fat-soluble substances toward water-soluble forms. Phase II conjugation then attaches a molecule that makes the result excretable, through five enzyme families: glucuronosyltransferases, sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
The kidneys then clear it. Mean glomerular filtration rate in healthy young adults is about 125 millilitres per minute per 1.73 square metres — on the order of 180 litres of plasma filtered every day.
None of this requires input. There is no off switch to override and no queue to clear. And “boosting” it is not self-evidently desirable: the same Phase I enzymes that detoxify some compounds bioactivate others into more harmful metabolites.
The costs are not zero
The British Dietetic Association notes that detox teas generally work as laxatives, which is not risk-free, and that rapid weight loss on fasting-style regimens is mostly water and glycogen.
There is also a documented harm pathway. A 2018 case report in the American Journal of Kidney Diseases describes a 65-year-old woman with normal baseline kidney function who developed acute oxalate nephropathy after a green-smoothie cleanse. Biopsy showed abundant calcium oxalate crystals. Contributing factors were a remote gastric bypass and a recent course of antibiotics — a combination nobody screens for when a cleanse is bought in a shop.
Why people feel better anyway
They often do, and the explanation is not mysterious. A detox week typically means no alcohol, no cigarettes, more sleep, more vegetables, more water and more exercise, all at once. Those changes have real effects. They are simply not the effects being sold, and none of them require a product.
The useful question to carry into a shop is the one the Sense About Science team asked. Which toxin does this remove, and where is the measurement? Twenty years of regulatory files suggest you will not get an answer — and that the one company that gave a detailed one ended up in court over it.
Sources
- Klein AV, Kiat H. Detox diets for toxin elimination and weight management: a critical review of the evidence. Journal of Human Nutrition and Dietetics 2015;28(6):675-686.
- Acosta RD, Cash BD. Clinical effects of colonic cleansing for general health promotion: a systematic review. American Journal of Gastroenterology 2009;104(11):2830-2836.
- Voice of Young Science / Sense About Science. The Detox Dossier, 2009.
- Federal Trade Commission. Complaint, FTC v. Xacta 3000 Inc. (Kinoki Foot Pads), D.N.J., 2009; and FTC v. Teami LLC, 2020.
- Advertising Standards Authority. Detoxing (general), CAP advice; and rulings on Pukka Herbs Ltd (2018).
- Makkapati S, D’Agati VD, Balsam L. “Green Smoothie Cleanse” Causing Acute Oxalate Nephropathy. American Journal of Kidney Diseases 2018;71(2):281-286.
- British Dietetic Association. Detox diets, Food Fact Sheet.
