Can Vitamins and Supplements Prevent or Treat Diabetes?

Type 2 diabetes is a medical condition that happens when your blood glucose (sugar) is too high. For most people, it’s a life-long condition. It’s usually managed with lifestyle changes and prescription medications (oral and/or injectable diabetes medications). But what about over-the-counter (OTC) vitamins and supplements? Can these prevent or treat diabetes?

You may have come across products advertised as “supplements for diabetes” or vitamins to “replace your diabetes medication.” You might be intrigued, but you should also be skeptical. Very few supplements have shown a benefit in treating or preventing diabetes. Below, we’ll discuss seven supplements that have been studied for managing diabetes, and what the research has to say. 

1. Chromium

Chromium is a mineral that’s naturally found in the body. One of its jobs is to help control blood glucose levels. It does this by making insulin more effective. Insulin is a hormone made in the pancreas that prevents glucose levels from getting too high. In Type 2 diabetes, the body either doesn’t make enough insulin, or doesn’t respond normally to insulin.

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What the research says

Some evidence shows that people with diabetes have low levels of chromium. But whether chromium supplementation can help treat diabetes is unclear. 

For example, a review of over 20 randomized controlled trials (RCTs) — the best type of study to evaluate cause and effect — looked at whether chromium supplements lowered blood glucose and hemoglobin A1C (A1C). A1C is a blood test that measures your average glucose levels over the past 3 months. In this study, chromium doses ranged from 1.28 mcg to 1000 mcg. The most commonly used form of chromium was chromium picolinate. The study found that chromium supplements didn't significantly lower blood glucose or A1C levels.

But one small study showed that chromium picolinate 1000 mcg may be effective in helping your body respond to insulin (improving insulin resistance). People taking chromium also had less weight gain and less body fat.

The verdict

Currently, the American Diabetes Association (ADA) doesn't recommend routine chromium supplementation to treat Type 2 diabetes. The available research is inconclusive on whether chromium supplements are a valid treatment option for diabetes. 

2. Alpha-lipoic acid

Alpha-lipoic acid (ALA) is an antioxidant. It works by getting rid of free radicals (groups of atoms that can cause damage to your cells). ALA can improve blood circulation and minimize inflammation in the body. It may also help lower blood glucose levels.

What the research says

ALA has been studied to treat nerve damage caused by diabetes (diabetic neuropathy). In a 4-year study of over 450 people with diabetes taking insulin, 600 mg of ALA taken orally every day improved symptoms of neuropathy. Another smaller but more recent study showed similar results with the same dose of ALA. 

While these studies didn’t show that ALA lowered A1C or glucose levels, another study did. It included over 200 people with diabetic neuropathy, and found that taking ALA improved A1C. But the dose in this study was higher — 600 mg three times a day. 

The verdict

There’s some evidence that ALA may improve diabetic neuropathy. It’s usually well-tolerated, but it can cause side effects like headache and heartburn.

Don’t take ALA without talking to your healthcare provider. It’s not FDA approved to treat diabetes or diabetic neuropathy, and we still need more research to show how effective it is. Other medications FDA approved to treat diabetic neuropathy may be preferable. 

3. Vitamin D

Vitamin D is involved in many different processes in the body. It helps keep our bones and muscles strong. It also boosts our immunity and helps mantain calcium and glucose levels. 

Our body can make its own vitamin D when we’re exposed to ultraviolet (UV) light from the sun. It’s also naturally part of some foods, like oily fish, mushrooms, and egg yolks. It’s often artificially added to food (like cereals or milk), or taken as a supplement.

What the research says

People with low vitamin D levels may be at higher risk for Type 2 diabetes. But whether vitamin D supplements can help prevent or treat diabetes is unclear. 

Preventing diabetes

When it comes to preventing Type 2 diabetes, the research is mixed.

In one large study of almost 2500 people found that vitamin D supplements didn’t prevent prediabetes from progressing to diabetes. Prediabetes is when blood glucose levels are high, but not high enough to qualify for a diabetes diagnosis. People with prediabetes can end up developing diabetes, especially if they don’t make lifestyle changes, like losing weight. The dose in this study was 4000 international units (IU) a day.

A separate analysis looking at eight studies found that taking more than 2000 IU of vitamin D per day reduced the risk of prediabetes progressing to Type 2 diabetes. It also helped some people with prediabetes decrease their glucose levels back to normal. But these results were only seen in people who weren't considered to have obesity.And a third large study of over 80,000 women followed over the course of 20 years found that a combination of vitamin D (greater than 800 IU) and calcium (greater than 1200 mg) supplements lowered the risk of developing Type 2 diabetes by 33%.

Treating diabetes

Whether vitamin D can treat diabetes is also unclear. 

One analysis of over 19 studies found that vitamin D supplementation improved A1C and insulin resistance in people with diabetes. People taking vitamin D also needed less insulin than they did before taking vitamin D supplements. But only the short-term studies (less than 6 months) showed these effects. The long-term studies (greater than 6 months) didn’t find vitamin D supplements effective in improving diabetes.

Another study of over 40,000 people found that vitamin D supplements had no effect on improving blood glucose or insulin resistance in those with Type 2 diabetes. 

The verdict

There’s some evidence that vitamin D supplements may help prevent or treat diabetes. But other studies show no effect. We need more studies to show in what situations vitamin D supplementation may be beneficial.

Whether you have diabetes or not, maintaining adequate vitamin D levels is good for your health. If you have low vitamin D levels, your healthcare provider may recommend vitamin D supplements. If you’re interested in using vitamin D supplements specifically to prevent or treat diabetes, talk to your healthcare provider first. They can help you weigh the risks versus benefits.

4. Omega-3s

Omega-3 fatty acids (omega-3s) are polyunsaturated fatty acids (PUFAs). PUFAs are generally considered the healthiest type of fat. Omega-3s help your body build cells and provide them with energy. The human body doesn’t make enough omega-3s naturally. So it’s necessary to get them from food and/or supplements.

What the research says

Researchers have studied whether omega-3s can help lower insulin resistance and the risk of developing Type 2 diabetes. So far, this doesn’t seem to be true.

A 2019 review of over 80 RCTs looked at whether omega-3s and other PUFAs could prevent or treat Type 2 diabetes. No significant effect was found. And other studies (including this review of 23 studies) had similar results. 

However, there’s some evidence showing that omega-3s can reduce the risk of heart disease in people with diabetes. This is important to note because people with diabetes are twice as likely to have heart disease.

The verdict

There’s no strong evidence that omega-3 supplements prevent or treat diabetes. 

Omega-3s are important for overall health, and most people get enough from their diet. Still, some people may benefit from an omega-3 supplement. Talk to your healthcare provider about whether a supplement is right for you.

5. Magnesium

Magnesium is an important mineral your body needs to function properly. The body doesn’t make magnesium on its own. It usually comes from the food you eat and can also be taken as a supplement. Some of magnesium’s main functions are helping your nerves and muscles work well, keeping your immune system strong, and maintaining a steady heartbeat. It also helps regulate blood glucose levels.

What the research says

Low magnesium levels may be more common in people with diabetes. And low magnesium levels may contribute to the progression of prediabetes to diabetes.

For example, an analysis of seven studies (including over 280,000 people) found that increasing magnesium intake by 100 mg per day (with food or supplements) decreased the risk of developing diabetes by up to 15%. But when it comes to treating diabetes, the research is mixed on whether magnesium intake has an effect. Some studies show that magnesium supplements may lower glucose levels, but others show no effect.

The verdict

We don’t have enough evidence to say whether magnesium supplements effectively prevent or treat diabetes. If you have prediabetes or diabetes, talk to your healthcare provider about checking your magnesium levels. If it’s low, they may recommend a supplement. But don’t take magnesium without talking to your provider first.

6. Vitamin C

Vitamin C is found in some foods and supplements. Your body can’t make enough of it on its own. It’s involved in many bodily processes, like maintaining a strong immune system and increasing how much iron your body absorbs from food. It also helps protect the body against free radicals.

What the research says

A high level of free radicals may contribute to the development of diabetes. Because vitamin C can protect the body against free radicals, vitamin C supplements have been studied as a treatment option for diabetes.

For example, an analysis of over 28 studies (and over 1500 people) found that vitamin C supplementation improved blood pressure and A1C in people with Type 2 diabetes. But most of these studies only followed people for less than 6 months and were small (less than 100 people per study).

The verdict

There’s not enough evidence to recommend a vitamin C supplement for people with Type 2 diabetes. We need larger, long-term studies to determine whether this is beneficial.

7. Herbal supplements

Herbal supplements contain ingredients found in herbs and other plants. These products are often labeled as “natural” products, and many people may try them to maintain their health. 

What the research says

You might be curious about using herbal supplements for controlling diabetes. Some herbal products that have been studied in preventing or treating diabetes include:

• Cinnamon

• Bitter melon

• Green tea

• Turmeric

• Ginseng

• Chinese herbal products 

Most studies on these herbal products are short-term studies that don’t include many people. They don’t provide enough data to say whether herbal supplements may have a role in preventing or treating diabetes. 

The verdict

We need more RCTs on herbal products before we can say whether they are effective at preventing or treating Type 2 diabetes. Though many of these products are labeled as natural, they have side effects and risks. They may also interact with many medications. Talk to your healthcare provider or pharmacist before taking an herbal supplement. They can help you check for drug interactions and weigh the risks and benefits.

Can vitamins or supplements cure diabetes?

No, vitamins or supplements are not proven to cure diabetes. 

For some people, lifestyle changes may be enough to keep diabetes under control. For others, a combination of lifestyle changes and prescription medications is most helpful. And despite what marketing claims might say, no vitamin or supplement can replace a diabetes medication that your healthcare provider prescribes you.

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Written by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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