Can Getting Too Much Vitamin D Cause a Rash?

Vitamin D plays many important roles in the body. According to the National Institutes of Health, it can improve your immune health and reduce the risk of health conditions such as heart disease and multiple sclerosis. It can also support your bone health and prevent osteoporosis.

You can get vitamin D in three ways: food, sun exposure, and supplements. But many people have difficulty getting enough through food and sunlight alone, which is often where supplements come in. Taking supplements can help you reach adequate levels, but too much may lead to vitamin D toxicity, or hypervitaminosis D. It’s uncommon, but it can cause uncomfortable, yet treatable, symptoms, like a skin rash, as well as nausea and vomiting.

Too Much of a Good Thing

It is possible to get sick from getting too much vitamin D, according to the Mayo Clinic. This is typically caused by taking high doses of vitamin D supplements, rather than eating too many vitamin D–rich foods like fatty fish and egg yolks or being outside in the sun for too long.

This condition isn’t life-threatening, but it can cause symptoms like frequent urination; nausea and vomiting; bone pain; kidney stones; and a skin rash, an itchy, red, and inflamed patch of skin.

While research published in 2024 suggests that vitamin D supplementation can improve atopic dermatitis — a skin condition characterized by dry, itchy skin — too much can also have the opposite effect.

“Those with either low vitamin D levels or high vitamin D levels may be susceptible to skin rash or skin irritations, although this is not a common occurrence,” says Lisa Diewald, RD, LDN, a registered dietitian-nutritionist and associate director of the MacDonald Center for Nutrition Education and Research at Villanova University in Pennsylvania. “Like any medication or supplement, it is possible to experience an allergic reaction to vitamin D that could cause a mild allergic reaction such as a skin rash or hives.”

While a skin rash or hives can be caused by sun exposure or eating certain vitamin D-rich foods, it’s most likely caused by taking too many vitamin D supplements, Diewald says, especially if you’re also experiencing other symptoms of vitamin D toxicity.

“Sunlight provides some of the vitamin D that we need, and the absorption of vitamin D from the sun will slow down as we meet our needs, so there is a built-in mechanism for preventing excess vitamin D from sunlight,” she adds. But that’s not the case with supplements. “Consumers should be mindful that more is not always better when it comes to supplements.”

Soothing the Rash

If skin irritation or rash occurs due to vitamin D use, it typically resolves after you stop taking it, Diewald says. “Stop taking the supplement, and observe for improvement,” she says. “If no improvement occurs or symptoms worsen, contact your physician for guidance.”

In the meantime, over-the-counter hydrocortisone creams or oral antihistamines such as loratadine (Claritin) can help relieve any itchiness related to most rashes.

Taking a warm bath with colloidal oatmeal can also help soothe irritated skin. You can buy colloidal oatmeal bath products, or you can make your own. The National Eczema Association advises grinding oatmeal into a fine powder and then slowly mixing 1/2 to 1 cup of the powder into the water as the bath is filling up.

Getting Your Daily Vitamin D

Most adults should aim for 600 IUs of vitamin D daily (800 IUs if you’re over 70 years old). That said, your healthcare provider may advise taking more vitamin D if you have a health condition that causes a deficiency.

But getting adequate vitamin D can be tough. “Dietary sources of vitamin D are limited, and include fortified milk, nondairy milks, and breakfast cereals, along with foods such as salmon and fish oil,” Diewald says. The amount of vitamin D you produce from being in the sun depends on how much time you spend outdoors, as well as your age and your skin tone.

Most adults do not get enough vitamin D every day. In fact, the Cleveland Clinic estimates that about 35 percent of people in the United States have a vitamin D deficiency. It can be caused by many factors, including limited sun exposure and certain health conditions, such as Crohn’s disease and celiac disease. So, taking the recommended amount of vitamin D can help you get adequate levels.

“Since adverse effects from excess vitamin D are likely to come from supplements and not dietary sources, try to optimize your dietary intake first, and be sure to spend some time in the sun to gain some additional vitamin D,” Diewald says.

“If you choose to take supplements, the tolerable upper limit — the maximum daily amount that is considered to be safe for most people — is 4,000 IU,” she adds.

If you’re concerned about your supplement regimen or are taking vitamin D regularly, it’s best to talk with your doctor about a safe and effective dose for your needs.