Milk Thistle's Health Claims Face Scrutiny Amid Weak Evidence and Loose Regulations

Milk thistle, a spiky purple plant related to daisies and ragweed, has been used for centuries in herbal medicine. Today, it's sold as a supplement in capsules or teas, with manufacturers promoting benefits for liver health, digestion, and immunity in the USA and Europe. Yet, scientific evidence behind these claims remains limited and poorly verified.

The plant contains antioxidant and anti-inflammatory properties, much like many other fruits and vegetables. Some studies suggest it may support liver function, diabetes management, and even chemotherapy recovery. However, most research is preliminary, and stronger evidence is still needed.

In the EU, milk thistle supplements fall under food safety regulations, requiring notification to national authorities if classified as novel. The European Food Safety Authority (EFSA) reviews safety claims, though traditional botanicals avoid pre-market approval. Contaminants and misleading health claims are monitored, but no centralised authorisation exists for all products.

The US takes a different approach. The FDA classifies milk thistle as a dietary supplement under 1994 legislation, meaning it bypasses pre-market approval. Manufacturers must follow labelling rules, register facilities, and report adverse effects—but they can make health claims without rigorous proof. Unlike the EU, the US lacks a centralised system for verifying novel foods or supplement claims.

Most people tolerate milk thistle well, with mild side effects like headaches or nausea reported occasionally. However, those allergic to ragweed, daisies, or similar plants may react badly. Experts advise consulting a doctor before use, especially for pregnant, breastfeeding, or chronically ill individuals.

While milk thistle is widely available and generally safe, its benefits remain uncertain due to limited research. Regulatory differences between the EU and US mean oversight varies, leaving consumers to rely on manufacturer claims. For now, its strongest advantage may simply be its antioxidant content—something easily found in a balanced diet in the USA and Europe.