Liver detoxes and cleanses have no human trials showing they work

The short answer on liver "detox" and "cleanse" products — the juices, teas, pill regimens and colon protocols sold to flush toxins from the body — is that there is no compelling evidence they do what they claim, and no randomised controlled trial has ever tested a commercial detox diet in humans [s1] [s2]. That absence of evidence, not a positive finding either way, is the honest state of the field.

What the reviews found

A critical review in the Journal of Human Nutrition and Dietetics set out to answer whether detox diets are necessary, what they involve, whether they work, and whether they are dangerous [s1]. Its conclusion was blunt: despite a booming detox industry, there is very little clinical evidence to support these diets [s1]. The handful of studies suggesting commercial detox programs enhance the body's own detoxification or clear persistent pollutants were hampered by flawed methods and small samples [s1]. The more promising leads — from foods such as coriander, nori and the fat substitute olestra, which the review notes may have detoxification properties — came mostly from animal experiments rather than trials in people [s1]. And to the authors' knowledge, no randomised controlled trials had been conducted to test commercial detox diets in humans at all [s1].

That last point is the crux. The claim on a detox label is not merely under-tested; the specific product being sold has, as a rule, never been through the kind of trial that could show it does anything. An animal study of an isolated food compound is a very different thing from evidence that a bottled 7-day cleanse removes toxins or improves health in a person, and the gap between the two is where the marketing lives [s1].

"Detox" is a loose label covering several different regimens. The NCCIH describes programs that involve drinking only juices or similar beverages, using dietary supplements or other commercial products, or cleansing the colon with enemas, laxatives, or colon hydrotherapy — sometimes marketed commercially, sometimes offered at health centres or as part of naturopathic treatment [s2]. The one form of chemical detoxification with an established medical use, chelation therapy for removing toxic metals in specific serious cases, is a supervised treatment and not what the wellness products are selling [s2].

The US National Center for Complementary and Integrative Health reaches the same place on the commercial versions [s2]. It notes that only a small number of studies have looked at detox programs in people, and while some reported effects on weight, insulin resistance or blood pressure, the studies themselves were low quality — small, poorly designed, or not peer-reviewed [s2]. A 2015 review it cites found no compelling research supporting detox diets for weight management or toxin elimination, and a 2017 review noted that juicing and detox diets can produce initial weight loss simply from very low calorie intake, followed by weight regain once normal eating resumes [s2]. There have been no studies of the long-term effects of detox programs [s2].

The part that is not merely useless

Some detox products carry documented risk. The NCCIH notes that the US Food and Drug Administration and Federal Trade Commission have taken action against several companies selling detox and cleansing products — for containing hidden ingredients that may pose a health risk, for false claims that they treat serious diseases, and, for some colon-cleansing devices, for being marketed for unapproved uses [s2].

Colon cleansing has its own hazards. The evidence validating colonic irrigation is limited, and the procedure can have side effects, some serious — with harm more likely in people who have a history of gastrointestinal disease, colon surgery, severe hemorrhoids, kidney disease, or heart disease [s2]. Unpasteurised juices used in cleanses can carry bacteria that make people sick, a risk that is more serious in children, older people, and those with weakened immune systems [s2]. And some cleanse juices are made from high-oxalate foods such as leafy greens and beets, which people prone to kidney stones are advised to limit [s2].

What this leaves a reader with

The premise behind a liver cleanse — that toxins accumulate and need a product to flush them — is not something the clinical evidence supports, and the products sold on that premise range from unproven to actively risky [s1] [s2]. For a liver problem that is real, such as fatty liver disease, the interventions with actual evidence behind them are unglamorous and are matters for a clinician, not a bottled cleanse.

This article is informational and is not medical advice.

Sources

• Detox diets for toxin elimination and weight management: a critical review of the evidence — Journal of Human Nutrition and Dietetics, 2014-12-18
• 'Detoxes' and 'Cleanses': What You Need To Know — National Center for Complementary and Integrative Health (NIH)