Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
The human liver weighs roughly one and a half kilograms, making it one of the body’s largest and hardest-working organs. It’s responsible for a wide range of essential functions, including breaking down fats, carbohydrates and proteins into forms the body can use for energy and repair.
The liver also acts as a storage hub for nutrients such as vitamins, minerals and glycogen, releasing them when the body needs an energy boost. For instance, when blood sugar levels drop, the liver releases stored glycogen to restore balance.
Another key role of the liver is to process and neutralise harmful substances. It converts toxins into less harmful compounds or removes them completely through waste. However, clever marketing has led many people to believe that ‘toxins’ come from certain foods, and that special diets or over-the-counter ‘liver cleanses’ can rid the body of these supposed impurities.
Many people think they can ‘detox’ their body through special diets or products. In reality, this idea is misleading.
To understand why, it helps to know what a toxin actually is. A toxin is a harmful substance that enters the body from the environment. Examples include carbon monoxide from car exhaust, bisphenol A (BPA) from plastics, and heavy metals, such as lead or mercury. Some drugs and poisons also fall into this category.
But toxicity depends on dose. Most of these substances only become dangerous in high concentrations. True medical detoxification occurs in hospitals, when doctors treat patients who have been exposed to life-threatening levels of toxins.
For everyone else, the liver is constantly working behind the scenes to remove unwanted substances through urine and faeces. These include natural byproducts of metabolism, such as those produced when digesting large amounts of protein, which, in excess, can put stress on the liver.
Despite this, many supplements and herbal products promise to ‘cleanse’ or ‘repair’ the liver. But does the liver actually respond to these remedies the way marketing suggests?
Most commercial liver detox supplements contain ingredients like Silybum marianum (milk thistle) and Taraxacum officinale (dandelion). Some blends also include nutrients and plant extracts, such as selenium, phosphatidylcholine, amino acids, artichoke leaf, green tea leaf and turmeric root.
While each company uses different ingredient combinations and dosages, the real question is whether these formulations have been proven to work.
Milk thistle extract, standardised to about 80% silymarin, is the most common ingredient in liver detox products. The use of milk thistle dates back to ancient Greece, when the physician Dioscorides recommended it for liver ailments.
Today, it’s still promoted as a liver tonic, but modern research tells a mixed story. Most studies on milk thistle are low in quality or poorly designed, leaving its effectiveness uncertain.
Some evidence suggests milk thistle, especially when combined with other ingredients, may help improve cholesterol levels, insulin resistance and inflammation. However, there’s no solid proof that it can ‘detoxify’ the liver as supplement labels often claim.
Dandelion has been used medicinally since the 10th century, mainly for treating liver and spleen issues. Over the years, researchers have studied it for various health conditions, but results remain inconsistent or are based on animal testing.
Like milk thistle, there’s no reliable evidence showing that dandelion extract helps the liver remove toxins or supports detoxification in humans. As such, it’s unlikely to deliver the ‘cleansing’ effects that many products advertise.
Looking for real, sustainable ways to support your body without resorting to detox fads? Read this article on what to eat when you’re hungry but trying to lose weight to learn how to nourish your body while still staying on track.
Maintaining a healthy liver doesn’t require fancy cleanses or supplements. The key is to eat a balanced diet and limit substances that force your liver to work overtime, particularly alcohol. Overeating or consuming too much of any single food can also strain the liver.
The best way to support your liver is to follow national dietary guidelines focused on whole foods, fruits, vegetables, lean proteins and healthy fats. This approach is far more effective (and affordable) than relying on products that lack scientific backing.
Curious about how everyday habits affect your health and weight goals? Read this article on whether snacking is bad for weight loss to see how small dietary choices can make a big difference to your wellbeing.
Complementary and herbal medicines are among the fastest-growing health markets globally. This makes it even more important for regulators to encourage companies to conduct proper research and ensure transparency in their claims.
Consumers deserve to know whether a product truly works and whether it’s safe. Evidence for one supplement shouldn’t automatically apply to another, as each formula uses different combinations and doses of ingredients.
For the latest updates on how complementary medicines are regulated, you can visit the Department of Health website, which provides information about the current review of Australia’s complementary medicine framework.
The liver doesn’t need help ‘detoxifying’ itself, as it’s already equipped to handle that job. Most detox products rely on clever marketing rather than strong evidence. To keep your liver functioning at its best, focus on balanced nutrition, moderate alcohol intake and maintaining a healthy lifestyle. That’s the real liver cleanse your body needs.
Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.