Who Found the Role of Chromium, and Why a Trace Mineral Became a Label Debate

The history of chromium starts with a 1959 rat study of a glucose tolerance factor and ends with a label debate over picolinate. It shows why a trace mineral's label claims run ahead of the trial record, and what current intake guidance actually says.

The history of chromium starts with rats, not people. In 1959, Mertz and Schwarz reported on a glucose tolerance factor in rats fed stock diets, and the paper's title never mentions chromium. The human evidence came later, and it has not settled into one clear answer. That gap is where the label debate sits. The form printed on a chromium bottle matters as much as the number, and the record behind each form is thinner than the labels suggest. ## In this article - A glucose factor in rats came first - Meta-analyses that point in different directions - The FDA drew a narrow line around picolinate - What labels show, and what adults need - Bottom line ## A glucose factor in rats came first In 1959, Mertz and Schwarz published a paper in the *American Journal of Physiology* titled "Relation of glucose tolerance factor to impaired intravenous glucose tolerance of rats on stock diets" ([PubMed](https://pubmed.ncbi.nlm.nih.gov/13627235/); [DOI](https://doi.org/10.1152/ajplegacy.1959.196.3.614)). PubMed has no abstract for it, and we could not confirm who coined the name "glucose tolerance factor." A decade later, Mertz's review in *Physiological Reviews* took up the broader question, "Chromium occurrence and function in biological systems" ([PubMed](https://pubmed.ncbi.nlm.nih.gov/4888391/); [DOI](https://doi.org/10.1152/physrev.1969.49.2.163)). Most readers hear the chromium part first, and it is easy to read more into the 1959 paper than its title supports. For the cell-level side of how the body handles fuel, see our [mitochondrial health guide](/health/mitochondrial-health-complete-guide). ## Meta-analyses that point in different directions The trials in the 2002 review measured glucose, insulin and HbA1c, and the 2014 review focused on HbA1c and fasting plasma glucose. A [2002 meta-analysis](https://pubmed.ncbi.nlm.nih.gov/12081828/) pooled 15 randomized trials with usable data, covering 618 people. It found no association between chromium and glucose or insulin concentrations in nondiabetic people, and it called the results in people with diabetes inconclusive ([DOI](https://doi.org/10.1093/ajcn/76.1.148)). A [2014 meta-analysis](https://pubmed.ncbi.nlm.nih.gov/24635480/) of 25 randomized trials in people with diabetes read the same question differently. Chromium supplementation significantly improved glycemic control, with HbA1c lower by a mean of 0.55 percentage points, and adverse events did not differ from placebo. The authors called the evidence on combined products limited and inconclusive, and they said long-term benefit and safety still need study ([DOI](https://doi.org/10.1111/jcpt.12147)). Body weight was measured too. The NIH summarizes the research, mostly on chromium picolinate, as showing a very small but statistically significant effect on body weight and body fat, with little clinical significance ([NIH ODS](https://ods.od.nih.gov/factsheets/Chromium-HealthProfessional/)). ## The FDA drew a narrow line around picolinate Picolinate is where the label debate sharpened. A [2006 review titled "Chromium picolinate intake and risk of type 2 diabetes: an evidence-based review by the United States Food and Drug Administration"](https://pubmed.ncbi.nlm.nih.gov/16958312/) reported that FDA issued a letter of enforcement discretion for one qualified health claim about chromium picolinate and insulin resistance, a surrogate endpoint for type 2 diabetes. The agency concluded that the relationship between chromium picolinate intake and insulin resistance is highly uncertain ([DOI](https://doi.org/10.1111/j.1753-4887.2006.tb00220.x)). The NIH says FDA allows only that one qualified claim for chromium picolinate supplements, and it quotes the claim as saying one small study suggests a possible link ([NIH ODS](https://ods.od.nih.gov/factsheets/Chromium-HealthProfessional/)). The narrow line follows from the mixed trial record described above. ## What labels show, and what adults need The NIH fact sheet focuses entirely on trivalent chromium, the form found in foods and supplements. Hexavalent chromium, by contrast, is a toxic by-product of stainless steel and other manufacturing processes ([NIH ODS](https://ods.od.nih.gov/factsheets/Chromium-HealthProfessional/)). On a supplement label, the number to read is elemental chromium. The NIH notes that elemental chromium makes up 12.4 percent of the weight of chromium picolinate, and that the Supplement Facts panel declares the elemental amount, not the weight of the whole compound. Forms differ, and the label names the one inside. Our [G.T.F. Chromium](https://mtangelvitamins.com/products/g-t-f-chromium-chromium-polynicotinate-with-niacin-for-blood-sugar-support-60-capsules?utm_source=learn_hub&utm_medium=content&utm_campaign=blog_post&utm_content=history-of-chromium-from-glucose-tolerance-factor-to-picolinate) lists 200 mcg of chromium from chromium polynicotinate, plus 10 mg of niacin, one capsule a day. The 60-capsule bottle is priced at $13.99, about $0.23 a day. Minerals such as [iron](/blog/history/history-of-iron-supplements-and-the-ferritin-test) and [calcium](/blog/history/history-of-calcium-supplements-from-chalk-to-bone-trials) followed their own routes from remedy to test. Adults need far less than that. The NIH sets adequate intakes at 35 mcg a day for men and 25 mcg for women, aged 19 to 50, with 30 mcg in pregnancy and 45 mcg while breastfeeding. The NIH uses an adequate intake when evidence is too limited to set a recommended dietary allowance. A 200 mcg capsule goes well beyond those estimates. ## Bottom line Read a chromium label for the form and the elemental amount, then compare it with the NIH adequate intake of 25 or 35 mcg a day. Treat the trial record as mixed. The 2002 meta-analysis found no effect in nondiabetic people, the 2014 review reported better glycemic control in people with diabetes, and FDA found the picolinate link highly uncertain. If you take glucose-lowering medication or are pregnant, check with a clinician before you add a high-dose product. ## Frequently asked questions ### What was the glucose tolerance factor, and who named it? The glucose tolerance factor appears in a 1959 paper by Mertz and Schwarz on impaired intravenous glucose tolerance in rats fed stock diets ([PubMed](https://pubmed.ncbi.nlm.nih.gov/13627235/)). PubMed has no abstract for that paper, and we could not confirm who coined the name, so this page does not credit anyone with it. Mertz's 1969 review in *Physiological Reviews* took up chromium's occurrence and function in biological systems ([PubMed](https://pubmed.ncbi.nlm.nih.gov/4888391/)). ### How did chromium move from a lab finding to a supplement? The verified path runs from rat studies in 1959 to a 1969 review, then to human trials that measured glucose, insulin and HbA1c. A 2002 meta-analysis found no link to glucose or insulin in nondiabetic people, while a 2014 meta-analysis reported improved glycemic control in people with diabetes. The regulatory record for picolinate starts with FDA's 2006 review, which judged the evidence highly uncertain. We could not verify the commercial steps, so this page does not describe them. ### Why did chromium picolinate become a regulatory debate? FDA's 2006 review, an evidence-based review by the agency, examined chromium picolinate and risk of type 2 diabetes, using insulin resistance as a surrogate endpoint. The agency issued a letter of enforcement discretion for one qualified health claim and concluded that the relationship was highly uncertain. The NIH says FDA allows only that one qualified claim for picolinate supplements. The debate is about how much a label can say when the trials disagree. ### Which forms of chromium appear on supplement labels? The NIH fact sheet focuses on trivalent chromium, the form found in foods and supplements. Chromium picolinate is the form most of the body-weight research used, and chromium polynicotinate is another form, so the label names the one inside. The Supplement Facts panel declares elemental chromium, which is 12.4 percent of the weight of chromium picolinate. Read the elemental number rather than the compound's total weight. ### What did the early human chromium trials measure? The 2002 meta-analysis covered trials that measured glucose, insulin and HbA1c, and the 2014 meta-analysis focused on HbA1c and fasting plasma glucose. The 2002 review found no association with glucose or insulin in nondiabetic people and called the diabetes results inconclusive. The 2014 review found improved glycemic control across 25 randomized trials of people with diabetes, with adverse events no different from placebo. Other trials, summarized by the NIH, measured body weight and body fat, with a very small, statistically significant change that has little clinical significance. ### How much chromium do adults need, according to current guidance? The NIH sets adequate intakes at 35 mcg a day for men aged 19 to 50 and 25 mcg for women of the same age. The intake is 30 mcg in pregnancy and 45 mcg while breastfeeding. An adequate intake is used when evidence is too limited to set a recommended dietary allowance. The NIH also cites a 2014 European Food Safety Authority review of dietary reference values for chromium. ### How do chromium label claims differ from the research findings? A label can name the nutrient and its form, but the research record is mixed. The 2002 meta-analysis found no effect on glucose or insulin in nondiabetic people, and the 2014 meta-analysis reported improved glycemic control in people with diabetes. Both called for more research. FDA allowed only one qualified claim for picolinate and judged that link highly uncertain. A label that suggests a benefit for everyone goes beyond that record.