Chromium

Barely, if at all. A meta-analysis in overweight adults found a loss of about half a kilogram versus placebo, which is small. One 8-week trial in 42 women with cravings found less hunger and fewer fat cravings on chromium picolinate, but no significant change in body weight. In men lifting weights for 8 weeks, chromium added no extra strength or muscle.

In people with diabetes, modestly. A 2014 meta-analysis of 25 randomized trials found lower HbA1c and fasting glucose, strongest above 200 mcg/day. In people without diabetes, a 2002 meta-analysis of 15 trials found no effect on glucose or insulin. A 2025 analysis in overweight adults found better glucose markers but a small rise in blood pressure.

At trial doses of 200–1,000 mcg/day, side effects were mostly mild: watery stools, headache, vertigo and occasionally hives. No upper limit has been set. Case reports describe kidney and liver injury in a woman taking 1,200–2,400 mcg/day for four to five months. Individual cases cannot show how often this happens, but they are why more is not better.

Ask first. In a small study of 7 healthy volunteers, chromium picolinate taken with levothyroxine reduced how much thyroid hormone was absorbed, so ask your doctor or pharmacist about spacing them several hours apart. With insulin or a sulfonylurea, chromium's own glucose-lowering effect could push blood sugar lower than intended.

No. Hexavalent chromium (chromium 6) is an industrial form, mainly encountered by inhalation, and is a recognized cause of lung cancer. Supplements contain trivalent chromium, a chemically different form. A 2-year government study of chromium picolinate in rats and mice, at doses thousands of times a human serving, found no clear cancer signal.