Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.
A range of dietary supplements are marketed as just the ticket to improving blood glucose, losing weight, or supporting heart health, but experts generally advise people with type 2 diabetes to avoid most of them.
“There’s not enough evidence to suggest taking supplements, and the effects differ depending on the person and their comorbidities,” says Joyce Y. Lee, PharmD, a health sciences clinical professor at the University of California Irvine School of Pharmacy and Pharmaceutical Sciences. Supplements aren’t a substitute for diabetes medication prescribed by your physician, and some supplements can interact with such diabetes medications, leading to high or low blood sugar.
More effective blood sugar management comes from lifestyle adjustments like eating a balanced diet and exercising regularly, says Dr. Lee. But if you’re still curious about supplementation, know that several vitamins, minerals, and plants should be avoided, and always consult your doctor before adding any dietary supplement to your wellness regimen.
1. Beta Carotene
Beta carotene is a compound that converts into vitamin A in the body. There’s some evidence that beta carotene can be beneficial for metabolic health. An antioxidant, beta carotene may decrease one’s risk of developing obesity and type 2 diabetes due to how it helps neutralize oxidative stress that leads to inflammation.
When consumed via whole foods like carrots, sweet potatoes, and dark leafy greens, beta carotene is safe and healthy. However, Lee recommends against taking beta carotene supplements.
“It’s a supplement that’s been shown to potentially contribute to cancer or worsen cardiovascular outcomes,” she says. “I think the harm outweighs the benefit, and if patients mention beta carotene supplementation, I discourage it.”
2. Bitter Melon
As its name suggests, bitter melon is a bitter, green, vine-growing fruit that looks like a cucumber and contains compounds that may affect glucose metabolism. Bitter melon supplements have been dubbed “natural insulin,” but the reality is a bit more murky, says Amy Kimberlain, RDN, CDCES, founder of Amy’s Nutrition Kitchen based in Miami.
“Studies are inconsistent, making it difficult to draw accurate conclusions about its safety and effectiveness,” she says, recommending that people with type 2 diabetes approach this supplement with caution. Taking bitter melon with other glucose-lowering medications could potentially lower your blood sugar levels too much.
Lee also points out that some people have glucose–6-phosphate dehydrogenase (G6PD) deficiency, a common genetic disorder that makes them more prone to anemia, which may be triggered by taking bitter melon. Your safest move is to consult your prescribing physician about bitter melon, so they can assess potential adverse reactions and medication interactions for you individually.
3. Chromium
Chromium, a mineral found naturally in whole grains, carrots, potatoes, broccoli, and molasses, is important for blood sugar control due to how it enhances insulin function. Problems can occur if you’re deficient in chromium, though most people get enough through their diet.
As important as chromium is for metabolic health, there’s no evidence that taking additional chromium via a dietary supplement will help someone with diabetes. “The American Diabetes Association doesn’t recommend the supplement, as there’s no clear benefit,” says Kimberlain. “Additionally, chromium in supplement form isn’t absorbed as [efficiently] as it is from food sources.”
Chromium supplements may interact with diabetes medications like insulin or sulfonylureas, lowering blood sugar too much when taken together. There are other potential health risks associated with chromium supplementation as well. “Chromium is usually not recommended, especially in people with preexisting kidney and liver issues,” says Lee. “Not everyone knows they have liver or kidney problems.”
4. Vitamin C
Vitamin C–rich foods like strawberries, bell peppers, and citrus can be part of a healthy diabetes diet. There’s also evidence that vitamin C supplementation may support glycemic control and healthy blood pressure.
However, you can run into problems with large doses of vitamin C, says Lee. “High-dose vitamin C could potentially mask low glucose levels, which can be a problem for people with diabetes who use tools and devices that measure their glucose such as continuous glucose monitors,” she says.
Lee recommends taking no more than 1,000 milligrams (mg) of vitamin C in supplement form per day, though read the manufacturer’s suggestion on your CGM, as some models specify that problems can occur at doses over 500 mg. If you’re interested in taking additional vitamin C, talk to your doctor first, especially if you use a CGM.
5. Cinnamon
Cinnamon is a spice that helps sweeten yogurt, oatmeal, and coffee without adding sugar. Adding the spice to your food isn’t a problem, and doing so may even help lower post-meal blood glucose levels.
However, the type, form, and dose of cinnamon matters. “While food amounts are safe, concentrated forms can affect liver health and blood sugar unpredictably,” says Kimberlain. Lee agrees that cinnamon in food is perfectly fine, but people should exercise caution with high-dose cinnamon supplements.
Cassia cinnamon, the type of cinnamon most commonly used in supplement form, is of particular concern, as it may contain high levels of a chemical called coumarin, which can be a safety issue for people with liver problems.
The biggest threat may be the fact that cinnamon has a reputation as a blood sugar-lowering spice that’s based on inconclusive science. “The effectiveness of cinnamon supplementation for diabetes or weight management remains uncertain, and more rigorous research is needed to confirm any potential benefits,” says Kimberlain.
The Takeaway
Many supplements marketed to people with type 2 diabetes claim to improve blood sugar or heart health, but experts warn they may be ineffective or even harmful.
Experts discourage using beta carotene, bitter melon, chromium, high-dose vitamin C, and cinnamon supplements due to safety concerns, drug interactions, or lack of proven benefits.
The safest approach for blood sugar management remains sticking with the medication and lifestyle changes that your clinician recommends, with supplements only taken under medical guidance and supervision.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Beta Carotene (Oral Route). Mayo Clinic. February 1, 2025.
Marcelino G et al. β-Carotene: Preventive Role for Type 2 Diabetes Mellitus and Obesity: A Review. Molecules. December 9, 2020.
Zhang Y et al. Association Between β-Carotene Supplementation and Risk of Cancer: A Meta-Analysis of Randomized Controlled Trials. Nutrition Reviews. September 2023.
Yang J et al. β-Carotene Supplementation and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. March 18, 2022.
The Effectiveness and Safety of Bitter Melon in the Management of Type 2 Diabetes Mellitus: A Review of Randomized Controlled Trials. Integrative and Complementary Therapies. December 13, 2023.
Romeo GR et al. Influence of Cinnamon on Glycemic Control in Individuals With Prediabetes: A Randomized Controlled Trial. Journal of the Endocrine Society. November 2020.
Sandy Bassin, MD, is an endocrinology fellow at Mount Sinai in New York City. She is passionate about incorporating lifestyle medicine and plant-based nutrition into endocrinology, particularly for diabetes and obesity management.
She trained at the Geisel School of Medicine at Dartmouth, where she taught culinary medicine classes to patients and medical trainees. She continued her training at the Robert Wood Johnson Medical School.
Dr. Bassin has published reviews of nutrition education in medical training and physical activity in type 2 diabetes in Nutrition Reviews, Endocrine Practice, and the American Journal of Lifestyle Medicine. She has been featured on the Physician to Physician Plant-Based Nutrition podcast and given many presentations on lifestyle interventions in endocrine disorders.
She stays active through yoga and gardening, and loves to cook and be outdoors.
Jessica Migala is a freelance writer with over 15 years of experience, specializing in health, nutrition, fitness, and beauty. She has written extensively about vision care, diabetes, dermatology, gastrointestinal health, cardiovascular health, cancer, pregnancy, and gynecology. She was previously an assistant editor at Prevention where she wrote monthly science-based beauty news items and feature stories.
She has contributed to more than 40 print and digital publications, including Cosmopolitan, O:The Oprah Magazine, Real Simple, Woman’s Day, Women’s Health, Fitness, Family Circle, Health, Prevention, Self, VICE, and more. Migala lives in the Chicago suburbs with her husband, two young boys, rescue beagle, and 15 fish. When not reporting, she likes running, bike rides, and a glass of wine (in moderation, of course).
