Chromium

What it is

Chromium in supplements is trivalent (+3) chromium, a trace element found naturally in many foods. It is different from hexavalent (+6) chromium, a toxic industrial by-product. Supplements use salts such as chromium picolinate, nicotinate, chloride and histidinate, and very little of any form is absorbed.

What the research says

The evidence is weak and contested. Chromium was long thought to help insulin work, and some meta-analyses report small drops in fasting glucose or HbA1c in type 2 diabetes, but the pooled trials are short, varied and inconsistent, and a well-run Western trial found no effect. A Cochrane review found about 1 kg extra weight loss of debatable clinical relevance from low-quality evidence. In 2014 EFSA concluded there is no convincing evidence that chromium is even an essential nutrient. Case reports link high-dose chromium picolinate to kidney and liver injury.

Evidence grade: Disputed.

What goes wrong

A case report describes a woman with anaemia, haemolysis, liver dysfunction and kidney failure needing haemodialysis after 4 to 5 months of 1,200 to 2,400 μg/day chromium picolinate; she recovered. (Source 1)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: 33-year-old woman taking chromium picolinate for weight loss.
• How long: 4 to 5 months.
• Result: aminotransferases 15 to 20 times normal; serum creatinine 5.3 mg/dL; plasma chromium 2 to 3 times normal.
• Funding: not applicable.

She had ingested chromium picolinate 1200–2400 μg/d for the previous 4–5 months to enhance weight loss.

Kidney failure has also been reported in a healthy young man after two weeks of chromium picolinate-containing supplements. (Source 2)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: 24-year-old healthy man.
• How long: 2 weeks.
• Result: reversible acute renal failure.
• Funding: not applicable.

24-year old healthy male reportedly developed reversible, acute renal failure after taking chromium picolinate-containing supplements for two weeks.

Chromium taken with levothyroxine reduced levothyroxine bioavailability by 17% in a small study, and chromium may add to the glucose-lowering effect of insulin and sulfonylureas. (Source 3)

• Official position, Low certainty.
• Size: small pharmacokinetic study (size not stated in source)
• Who: healthy volunteers.
• How long: single doses.
• Result: L-T4 bioavailability down 17%.
• Funding: not stated.

concomitant L-T4 and chromium picolinate at 1 mg each decreased L-T4 bioavailability by 17%

Position, NIH ODS (updated 2 June 2022): isolated case reports link chromium supplements to anaemia, thrombocytopenia, liver dysfunction, renal failure, rhabdomyolysis, dermatitis and hypoglycaemia. (Source 4)

• Official position, Certainty not rated.
• Size: case reports.
• Who: people taking chromium supplements.
• How long: varied.
• Result: not quantified.
• Funding: government.

According to isolated case reports, chromium supplements might cause weight loss, anemia, thrombocytopenia, liver dysfunction, renal failure, rhabdomyolysis, dermatitis, and hypoglycemia.

What the evidence supports

A trial of 180 people in China reported fasting glucose 15% to 19% lower after four months on 1,000 μg/day chromium picolinate than on placebo (as summarised by the Linus Pauling Institute). (Source 2)

• Randomized trial, Low certainty.
• Size: 180 participants.
• Who: adults with type 2 diabetes in China.
• How long: 4 months.
• Result: fasting glucose 15% to 19% lower at 1,000 μg/day.
• Funding: not stated.

After four months of treatment, fasting blood glucose concentrations were found to be 15% to 19% lower in those who took 1,000 μg/day of chromium compared to those who took the placebo.

What the evidence does not support

The Cochrane authors rated the evidence low quality and could not judge long-term efficacy or safety. (Source 5)

• Systematic review, Low certainty.
• Size: 9 RCTs.
• Who: overweight or obese adults.
• How long: maximum 24 weeks.
• Result: no firm conclusion possible.
• Funding: not stated.

We found no current, reliable evidence to inform firm decisions about the efficacy and safety of CrP supplements in overweight or obese adults.

A meta-analysis of 14 RCTs in type 2 diabetes found no significant effect of chromium picolinate, chromium yeast or brewer's yeast on HbA1c, and only brewer's yeast lowered fasting glucose. (Source 6)

• Meta-analysis, Low certainty.
• Size: 875 participants across 14 RCTs.
• Who: adults with type 2 diabetes, aged 30 to 83.
• How long: 8 to 24 weeks.
• Result: brewer's yeast FPG -19.23 mg/dL (95% CI -35.30 to -3.16, I2 = 21%, n = 137); no significant HbA1c effect for any form.
• Funding: not stated; authors declare no competing interests.

Compared with placebo, Cr yeast, brewer's yeast and Cr picolinate did not show statistically significant effects on A1C.

A 6-month double-blind RCT of 500 or 1,000 μg/day chromium picolinate in obese insulin-treated type 2 diabetes found no difference from placebo in HbA1c or secondary outcomes. (Source 7)

• Randomized trial, Moderate certainty.
• Size: 46 analysed per protocol.
• Who: obese Western adults with insulin-treated type 2 diabetes, HbA1c >8%.
• How long: 6 months.
• Result: HbA1c fell about 0.4% in all three groups equally; no differences in secondary end points.
• Funding: not stated.

In this per-protocol analysis (n = 46), the decrease in A1C was approximately equal across the three groups (0.4%).

A meta-analysis of nine RCTs in people without diabetes found chromium had no effect on fasting glucose (as summarised by the Linus Pauling Institute). (Source 2)

• Meta-analysis, Certainty not rated.
• Size: 309 individuals across 9 RCTs.
• Who: adults without diabetes.
• How long: 8 to 16 weeks; 200 to 1,000 μg/day.
• Result: no effect on fasting glucose.
• Funding: not stated.

reported that chromium at doses of 200-1,000 μg/day for 8-16 weeks had no effect on fasting glucose concentrations in 309 individuals without diabetes.

Position, EFSA (2014): no convincing evidence that chromium is an essential nutrient, so setting intake recommendations would be inappropriate. (Source 4)

• Official position, Certainty not rated.
• Size: not applicable.
• Who: general population.
• How long: not applicable.
• Result: not applicable.
• Funding: government.

In 2014, the European Food Safety Authority Panel on Dietetic Products, Nutrition and Allergies concluded that no convincing evidence shows that chromium is an essential nutrient and, therefore, setting chromium intake recommendations would be inappropriate.

Where the evidence is mixed

A Cochrane review found chromium picolinate produced about 1 kg more weight loss than placebo, of debatable clinical relevance, from low-quality evidence. (Source 5)

• Systematic review, Low certainty.
• Size: 622 participants across 9 RCTs.
• Who: overweight or obese adults.
• How long: 8 to 24 weeks.
• Result: about 1 kg more body weight lost than placebo; only 3 of 9 trials reported adverse events.
• Funding: not stated.

study participants lost around 1 kg of body weight more than participants receiving placebo

The same meta-analysis flagged high heterogeneity as a limitation. (Source 6)

• Meta-analysis, Low certainty.
• Size: 14 RCTs.
• Who: adults with type 2 diabetes.
• How long: 8 to 24 weeks.
• Result: heterogeneity limits the pooled results.
• Funding: not stated.

The high level of heterogeneity may be a limiting factor of this study.

A 2024 systematic review of RCTs reported that several trials found lower glycaemic markers with chromium, mostly in longer trials, but that most studies had significant limitations. (Source 8)

• Systematic review, Low certainty.
• Size: RCTs from 2000 to January 2024 (number not given in abstract)
• Who: adults with type 2 diabetes.
• How long: 2 to 6 months; 50 to 1000 μg/day.
• Result: FPG, insulin, HbA1c and HOMA-IR reported to decrease in several trials; no pooled estimate.
• Funding: not stated.

However, most research findings include significant limitations, such as inconsistent dosage and type of chromium, formulation of supplements, and study duration.

Where the research disagrees

Whether chromium is an essential nutrient

• US Food and Nutrition Board (2001), via NIH ODS, position based on usual intakes: The FNB therefore established AIs for all ages based on usual chromium intakes in healthy populations. (Source 4)
• European Food Safety Authority (2014), position: no convincing evidence shows that chromium is an essential nutrient (Source 4)

Whether chromium improves blood sugar in type 2 diabetes

• 2024 systematic review of RCTs, systematic review of RCTs: Glycemic control markers, including FPG, insulin, HbA1C, and HOMA-IR levels, significantly decrease following chromium supplementation, mainly in studies with a longer intervention period. (Source 8)
• Kleefstra et al. 2006, Diabetes Care, RCT: There is no evidence that high-dose chromium treatment is effective in obese Western patients with type 2 diabetes. (Source 7)

How much

• Reference intake: US Food and Nutrition Board (2001) set Adequate Intakes, not an RDA, based on usual intakes: 35 mcg/day men 19-50, 25 mcg/day women 19-50, 30 and 20 mcg/day from age 51 (NIH ODS 2022, Table 1). EFSA (2014) set no requirement or adequate intake. (Source 4)
• Upper limit: No UL. The US Food and Nutrition Board (2001) did not set one because no adverse effects had been linked to high intakes from food or supplements. (Source 4)
• Studied: 500 or 1,000 μg/day chromium picolinate for 6 months in insulin-treated type 2 diabetes (Kleefstra 2006). (Source 7)
• Studied: 1,200 to 2,400 μg/day chromium picolinate self-taken for 4 to 5 months in a case of kidney and liver injury. (Source 1)

A common belief, and what the research shows

The belief: Chromium picolinate is a proven aid to weight loss.

What the research shows: A Cochrane review found about 1 kg more weight loss than placebo, 'of debatable clinical relevance after 12 to 16 weeks of treatment', and 'The overall quality of evidence was considered low'.

Questions and answers

What is it?

Chromium in food and supplements is trivalent chromium, a trace element found in many foods. It is not the same as hexavalent chromium, which is a toxic industrial by-product. (Source 4)

What does it do in the body?

It is thought to help insulin act, but this is uncertain. Some trials report small drops in blood sugar in type 2 diabetes, and the clinical meaning of those drops is unclear. (Source 4)

Is it good or bad for you?

From food it appears harmless. As a supplement the benefits are small and uncertain, and high doses of chromium picolinate have been linked in case reports to serious kidney and liver injury. (Source 1)

How do you get more of it?

Chromium comes from a wide range of foods. Supplements come in several salt forms, and chromium picolinate is absorbed a little better than chromium chloride, though both are absorbed poorly. (Source 4)

If it is harmful, what reduces it?

Excess chromium from supplements is dealt with by stopping them. In the case report of kidney and liver injury, the patient recovered on supportive care, including dialysis. (Source 1)

Why might someone be low in it or missing it?

Deficiency is not seen in healthy people. Suspected cases have occurred only in people on long-term intravenous feeding without added chromium. (Source 4)

Which whole foods contain it or feed it?

Meats, whole grains, fruits, vegetables such as broccoli and green beans, nuts, spices, brewer's yeast, beer and wine all contain chromium. Levels vary with soil and processing, and most dairy and sugary foods are low. (Source 4)

What happens if you do not have it?

No deficiency disease is established. In patients on long-term intravenous feeding without chromium, abnormal glucose handling that responded to chromium has been described. (Source 2)

How can you test for it?

There is no validated test of chromium status. Blood chromium can be measured, but it does not define deficiency. (Source 4)

References

1. Annals of Pharmacotherapy. Chromium Picolinate Toxicity. 1998. PMID 9562138, DOI 10.1345/aph.17327. Read the source
2. Linus Pauling Institute Micronutrient Information Center, Oregon State University. Chromium. n.d.. Read the source
3. Memorial Sloan Kettering Cancer Center. Chromium (About Herbs; last updated February 24, 2022). 2022. Read the source
4. NIH Office of Dietary Supplements. Chromium: Fact Sheet for Health Professionals (updated June 2, 2022). 2022. Read the source
5. Cochrane. Chromium picolinate supplementation for overweight or obese adults (Cochrane review, plain language summary). 2013. PMID 24293292, DOI 10.1002/14651858.CD010063.pub2. Read the source
6. Nutrition Journal. Effect of chromium supplementation on glycated hemoglobin and fasting plasma glucose in patients with diabetes mellitus. 2015. DOI 10.1186/1475-2891-14-14. Read the source
7. Diabetes Care. Chromium treatment has no effect in patients with poorly controlled, insulin-treated type 2 diabetes in an obese Western population: a randomized, double-blind, placebo-controlled trial. 2006. PMID 16505499. Read the source
8. Environmental Geochemistry and Health. Chromium supplementation and type 2 diabetes mellitus: an extensive systematic review. 2024. DOI 10.1007/s10653-024-02297-5. Read the source