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Bottom Line: Clinical trials show that chromium supplements generally do not work for building muscle mass or losing weight. Even though chromium lowers blood glucose in some people, we do not know how it interacts with diabetes medications or what its long-term effects are. Chromium picolonate may be dangerous.

Chromium is an element that is required by the body in very small amounts (0.025 mg a day). Adequate amounts are usually obtained in the diet, from foods like American cheese, meat, fish, fruits, and whole grains. Based on laboratory experiments, scientists think that chromium is involved with maintaining adequate levels of glucose, fats, and insulin activity in the body. Specifically, chromium probably interacts with insulin receptors on cells and enhances the many effects of insulin on cells, including improved glucose uptake. In theory, this would help in type 2 diabetes, since this disease results from a decreased effect of insulin on cells.

Chromium is sometimes combined with GTF (Glucose Tolerance Factor) in over-the-counter products. GTF is a yeast extract that facilitates glucose metabolism in laboratory studies, but this effect has not been confirmed in humans.

Weight loss and muscle gain:
Several clinical trials have tested chromium supplements to see whether they are effective for losing weight and gaining muscle mass. However, most of these clinical trials were small and had inconclusive results. Right now, no clinical trial supports the use of chromium supplements for weight loss or improvements in muscle mass.

Type 2 diabetes:
The use of chromium supplements for treating type 2 diabetes was tested in a randomized controlled trial. For four months, 180 patients took either 100 micrograms of chromium, 500 micrograms of chromium, or a placebo pill twice daily. Both of the groups taking chromium had lower fasting glucose and postprandial (after eating) blood glucose levels than the placebo group. This suggests that chromium is helpful in reducing blood glucose levels in patients with type 2 diabetes, but this study did not address the long-term effects of chromium, and what happens when it is discontinued in these patients. 

According to the FDA, it is 'highly uncertain' that chromium picolinate reduces the risk of insulin resistance and type 2 diabetes.

This product is regulated by the F.D.A. as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.

Trivalent chromium

Chromium III, chromium picolinate, niacin-bound chromium, chromium chloride

Chromium, a naturally occurring element obtained from food, is considered an essential trace element. Patients take this supplement for diabetes, weight loss, and to improve muscle mass. Chromium is poorly absorbed following oral administration, although the salt forms (e.g. chromium picolinate, niacin-bound chromium, and chromium chloride) appear to have better bioavailability. Chromium is believed necessary for glucose and lipid metabolism. It is involved with the activity of insulin ^{(1) (2)}. The role of chromium in weight loss or muscle mass improvement is unclear. Most clinical trials have inadequate sample size or other major design flaws ^{(11) (12) (13) (14) (15) (16)}. Chromium supplementation appears effective in lowering glucose and insulin levels in type 2 diabetics, although additional studies are required ⁽¹⁷⁾. But the FDA has recently issued a letter stating that chromium picolinate does not reduce the risk of insulin resistance or type 2 diabetes ⁽¹⁸⁾. Reported adverse effects for chromium include sporadic case reports of renal failure ^{(4) (8)}, rhabdomyolysis ⁽⁵⁾, liver damage ⁽⁶⁾, and dermatitis ⁽³⁾. Chromium requires transferrin to be absorbed and is renally eliminated ⁽⁶⁾; therefore patients with renal and hepatic dysfunction should not be routinely supplemented. To date there are no known drug interactions. Optimal dosage remains undetermined. GTF or Glucose Tolerance Factor is extracted from yeast and frequently combined with chromium in commercial products. Some studies suggested GTF can facilitate glucose metabolism in animals ⁽¹⁰⁾. However, its effect in humans is inconclusive.

Liver, American cheese, brewer's yeast, wheat germ, meat, fish, fruits, whole grains, brown sugar, alfalfa, and animal fats
⁽¹⁾

Chromium is an essential trace element involved with glucose and lipid metabolism, circulating insulin levels, and the peripheral activity of insulin ⁽¹⁾. In vitro and in vivo studies suggest that chromium potentiates the activity of insulin ⁽⁹⁾. This is thought to occur via enhanced intracellular tyrosine kinase activity that results from an interaction between chromium, low molecular weight chromium-binding substance and activated cell surface insulin receptors ⁽²⁾.

Absorption:
The bioavailability of trivalent chromium is relatively low, ranging from 0.4 to 2.5% of the orally administered dose. Chromium picolinate, trivalent chromium bound to picolinic acid, has a bioavailability of approximately 3%.
Distribution:
Trivalent chromium binds to transferrin and albumin. It distributes throughout the body, but appears to concentrate in the kidney, liver, soft tissue, and spleen. Chromium fits a three compartment pharmacokinetic model.
Excretion:
The biological half-life for urinary excretion of chromium ranges from 0.97-1.51 days. Unabsorbed chromium is excreted in the feces while absorbed chromium is primarily eliminated renally.

Patients with liver or renal insufficiency may have increased susceptibility to adverse effects.
⁽⁷⁾

Rare: Hepatic toxicity ⁽⁶⁾
Case reports: Two cases of renal failure ^{(4) (8)}; one case of acute generalized exanthematous pustulosis, characterized by erythematous lesions, fever, edema, leukocytosis, and eosinophilia ⁽³⁾; one report of rhabdomyolysis in a patient taking chromium picolinate in addition to other dietary supplements ⁽⁵⁾.

Sulfonylureas / Insulin: Theoretically, chromium may have additive hypoglycemic effects.

Lower Hgb A1c, blood glucose, serum insulin, total cholesterol
Small increase in HDL

Several clinical trials have evaluated the efficacy of chromium supplementation for weight loss and muscle mass ^(11-17). Most trials had small sample sizes and conclusive data is lacking. To date, no study supports the use of chromium supplements for weight loss or improvements in muscle mass.

Anderson RA, et al. Elevated intakes of supplemental chromium improve glucose and insulin variable in individuals with type 2 diabetes. Diabetes 1997;46:1786-91.
A prospective, double-blind, randomized evaluation of chromium supplementation in type 2 diabetic patients ages 35-65 years. A total of 180 patients were randomized to 4 months of placebo, 100 mcg chromium twice daily, or 500 mcg chromium twice daily. Primary outcomes measured were change in fasting glucose, hemoglobin A1c, fasting insulin, and 2 hour post prandial glucose levels. The authors report that patients receiving 500 mcg chromium twice daily had statistically significant lower fasting glucose and 2 hour post prandial glucose levels at 2 and 4 months. Both treatment groups had significantly lower fasting and 2 hours post prandial insulin levels at 2 and 4 months, and hemoglobin A1c levels at four months decreased by 1-2 grams per deciliter in each treatment group. The authors did not publish actual baseline values and the statistical methods used are questionable. No adverse events were reported. The long-term effect and withdrawal of chromium supplementation is not addressed.