How much B6 is safe? What to know about the supplement found in energy drinks

There is growing awareness of the rare but potentially serious side effects associated with high doses of vitamin B6, a nutrient that has become popular in a range of dietary supplements, electrolyte drinks and fortified foods.

Vitamin B6, or pyridoxine, is a nutrient essential for many bodily functions, including nerve health, protein metabolism, and blood sugar regulation. Since vitamin B6 is also essential for brain development, it is important during pregnancy and early childhood. It is often promoted to help increase energy and relieve stress.

It occurs naturally in many foods and is added to a number of ready-to-eat products, including cereals. Most multivitamins contain B6, according to the National Institutes of Health’s Office of Dietary Supplements.

Some energy drinks also contain it as an alternative to caffeine, said Jamie Alan, associate professor of pharmacology and toxicology at Michigan State University.

“People might be surprised how many places B vitamins are present,” she said.

That’s part of the problem.

In high doses, B6 can build up in body tissues and cause nerve damage, said neurologist Dr. Norman Latov, director of the Peripheral Neuropathy Clinical and Research Center at Weill Cornell Medicine in New York.

In November, suspected vitamin B6 poisonings prompted the Australian government to tighten restrictions on supplements containing large amounts of the nutrient. From mid-2027, products containing more than 50 milligrams per daily dose will be sold over the counter in pharmacies; those exceeding 200 mg already require a prescription.

Yet vitamin B6 products continue to grow in popularity. Their global market share is expected to exceed $712 million by 2030, with a compound annual growth rate of 5.8% from 2024 to 2030, according to research analytics firm IndustryArc.

Poisonings are rare, although their incidence is increasing. Nationally, 439 cases of vitamin B6 exposure were reported in 2024, none of which were fatal, compared to 369 in 2019 and 311 in 2014, according to records from the National Poison Data System.

Joanne Slavin, a registered dietitian and professor of food science and nutrition at the University of Minnesota, said many people assume that water-soluble vitamins, including B6, are harmless. Unlike fat-soluble vitamins, which are stored in the liver, muscles and fatty tissues, water-soluble vitamins are released in urine and therefore must be consumed regularly.

“People need to understand that vitamins are not inert, they are chemicals,” Slavin said. “You don’t need to overdo it.”

B6 toxicity may be underestimated because symptoms develop gradually and consumers may not realize they are consuming too much. “It gets under your skin,” Latov said, estimating that 5 to 10 percent of neuropathy patients at the Weill Cornell Center have elevated B6 levels.

The first signs are occasional numbness in the toes, which may be ignored, followed by a hot, cold, tingling or tingling sensation that starts in the feet and can travel up the leg, Latov said.

Other symptoms may include nerve pain, numbness, imbalance, muscle weakness, and changes in blood pressure, as well as fatigue, heartburn, and nausea.

A blood test can determine if B6 levels are excessive.

“There is a pretty large margin of safety for B6, meaning you can take a decent amount beyond the recommended dose and still be fine,” Alan said. “But anything given in a high enough dose will have harmful side effects, even water.”

Colorado woman recounts ‘scary’ vitamin B6 poisoning

When Blair Huddy moved from California to Colorado in 2024, she said everyone advised her to stay hydrated, in part because dehydration can worsen the effects of altitude sickness.

So Huddy, now 36, started using an electrolyte drink mix in December of that year. She said she consumes the product once a day as directed, mixing one sachet with 16 ounces of water. The label says each sachet contains 1.93 mg, or 110% of the recommended daily intake, of vitamin B6.

Huddy immediately said she began experiencing unexplained symptoms of dizziness, heart palpitations and adrenaline rushes. Unaware of a possible link, she continued to use the electrolyte packets. In January 2025, she also had seasonal allergy-like symptoms, and soon after, she began having trouble sleeping. In March, she tried chicken liver for the first time – organ meats are rich in vitamin B6 – and was hospitalized with suspected anaphylaxis and heart complications. She had never had an allergic reaction to a food before and said doctors couldn’t explain it.

“It was really scary. I had no idea what was happening to me,” Huddy said. “I continued to consume one [drink mix packet] every day, thinking I was just hydrating.

After being released from the hospital, Huddy developed peripheral neuropathy, a generic term for diseases affecting the nervous system outside of the brain and spinal cord, as well as tinnitus.

“I kept coming back to the doctor and thinking, ‘Something is seriously wrong,'” Huddy said, adding that she was told her symptoms were a product of her generalized anxiety disorder. “I was constantly getting fired and sent home.”

In May, Huddy said she begged a doctor to do blood tests.

“A nurse from the doctor’s office called me and said, ‘Your vitamin B6 levels are more than twice the upper limit,'” Huddy said. “Whatever you are taking that contains B6, you need to stop. »

What is the safe amount of vitamin B6?

Recommended daily B6 requirements range from 1.3 mg for young adults to 1.5 mg for women over 50 and 1.7 mg for older men.

Foods rich in vitamin B6 include poultry, fish, beef liver and other organ meats, potatoes and other starchy vegetables, and fruits other than citrus. Most people get enough from their diet, experts say.

The United States has a relatively high upper limit of vitamin B6 for adults: 100 mg. The European Food Safety Authority, for example, has set a maximum of 12 mg per day. The limit is 50 mg in Australia.

The Council for Responsible Nutrition, a trade association representing supplement manufacturers, has established its own B6 supplement upper limit of 100 mg per day. This is the amount that can be safely consumed by the healthy general population, said Andrea Wong, the group’s senior vice president and chief scientific officer. People with certain health conditions may need or tolerate more or less.

“It will depend on the individual and your body’s metabolism and its ability to process the vitamin,” Wong said, later adding: “There are so many other factors that can contribute to the potential effect you experience.”

A small 2020 study published in the journal PharmaNutrition found that factors such as diet, genetics, and medication use can affect vitamin B6 toxicity, even at the recommended daily amount.

Vitamin B6 may appear on nutrition labels under the names pyridoxine, pyridoxal or pyridoxamine, referring to its different chemical forms.

“Make sure you look at all the different sources you use and add up that total amount to make sure you’re getting what’s right for you,” Wong said.

Vitamin B6 can stay in the body for 30 to 40 days. If you stop taking it, symptoms should improve, Latov said, although “depending on the extent of the damage, the nerves may not completely regenerate.”

Huddy blames her poisoning on the electrolyte drink mix she consumed daily for six months. She doubts her diet is a factor and says she hasn’t taken any other supplements.

She continues to recover, although she suffers from persistent tinnitus and undergoes physical therapy for nerve problems. She started working again and took on another unofficial job: providing support to other people suffering from vitamin B6 poisoning.

“I wish I had someone who could help me through this the same way I’m now able to support other people,” Huddy said.

This article was originally published on NBCNews.com