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Limited evidenceHeart & metabolic

Chromium

Chromium picolinate is sold for blood sugar and weight loss on the strength of noisy, low-quality meta-analyses. The pooled weight-loss effect is half a kilogram, the glycaemic findings are drowned in near-total heterogeneity, and chromium's status as an essential human nutrient is itself now disputed.

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What the science says

  • Weight loss effect is real but trivially small Limited evidence

    A meta-analysis of 20 included trials, 11 pooled, found chromium beat placebo for weight loss by 0.50 kg (95% CI 0.03-0.97 kg), with high statistical heterogeneity and variable reporting quality. Half a kilogram over several months is clinically meaningless; the review's own authors stated the magnitude is small and the clinical relevance uncertain.

  • Glycaemic effects are unreliable Limited evidence

    A 2020 meta-analysis of 28 trials in type 2 diabetes reported reductions in fasting glucose (-19.0 mg/dL, 95% CI -36.15 to -1.85) and HbA1c (-0.71%, 95% CI -1.19 to -0.23) — but with I-squared of 99.8% for fasting glucose, meaning the trials disagree so violently that the pooled number carries little information. An earlier AJCN meta-analysis found no effect on glucose or insulin in people without diabetes, and well-conducted trials in metabolic syndrome have been null.

  • Not established as an essential nutrient Limited evidence

    No unambiguous case of dietary chromium deficiency has ever been described in a person eating ordinary food, and no chromium-dependent human enzyme has been identified. The European Food Safety Authority concluded chromium is not essential for humans and declined to set an intake recommendation. The "glucose tolerance factor" story that launched the entire supplement category has not held up.

Dosage & safety

Studied doseThe US adequate intake is 35 mcg/day for men and 25 mcg/day for women, derived from observed dietary intakes rather than any measured requirement. Trials use 200-1,000 mcg/day of chromium picolinate or chromium chloride, most commonly 400-600 mcg/day for 8-24 weeks. Picolinate is absorbed better than chloride, but neither form has a demonstrated clinical advantage over the other or over nothing.
SafetyGenerally well tolerated; adverse events reported in trials include watery stools, headache, vertigo and urticaria. There are isolated case reports of renal impairment, rhabdomyolysis and hepatotoxicity with high-dose chromium picolinate, and picolinate has raised unresolved in vitro genotoxicity concerns. Do not confuse trivalent chromium (the supplement form) with hexavalent chromium, an industrial contaminant and established carcinogen — they are chemically and toxicologically distinct. Chromium may add to the glucose-lowering effect of insulin, sulfonylureas and other antidiabetic drugs, so anyone on those should monitor blood glucose. Use caution in kidney or liver impairment; avoid in pregnancy above dietary amounts given the absence of safety data.

How to take it

TimingTiming does not matter, though trials generally split the dose across meals.
With food?With food.
Worth knowingTrivalent chromium in supplements is not the hexavalent chromium of industrial pollution scares — but that safety point is not evidence it does anything for blood sugar.

Interactions

With medications

  • insulin, sulfonylureas and other antidiabetic drugs

    Chromium may add to their glucose-lowering effect. monitor blood glucose closely and tell your doctor you have started it

  • levothyroxine

    Chromium picolinate significantly reduces levothyroxine absorption. separate by at least 3-4 hours

With other supplements

  • iron

    Chromium and iron compete for binding on transferrin, and high-dose chromium may lower iron status over time. separate doses and check ferritin if you take chromium long-term

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does chromium picolinate work for weight loss?

Barely — the evidence is limited. A meta-analysis found chromium beat placebo by only 0.50 kg, an amount the review's own authors called small and of uncertain clinical relevance.

Does chromium lower blood sugar?

The evidence for chromium and blood sugar is limited and unreliable. Pooled diabetes trials disagree so sharply that the average effect carries little information, and trials in people without diabetes found no effect on glucose or insulin.

How much chromium per day?

The US adequate intake for chromium is 35 mcg/day for men and 25 mcg/day for women. Trials used 200–1,000 mcg/day, but no chromium dose or form has a demonstrated clinical advantage over nothing.

Is chromium safe with diabetes medication or levothyroxine?

Chromium may add to the glucose-lowering effect of insulin and sulfonylureas, so monitor blood glucose and tell your doctor. Chromium picolinate also reduces levothyroxine absorption, so separate them by at least 3–4 hours.

Scientific references

Where to buy

NOW Foods, Chromium Picolinate, 200 mcg, 250 Veg Capsules

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