Experts worry B6 toxicity from electrolyte drinks or supplements is rising. Here’s what to know

There’s growing awareness of rare, but potentially serious side effects from high doses of vitamin B6, a nutrient that’s become popular in a range of dietary supplements, electrolyte drinks and fortified foods.

Vitamin B6, or pyridoxine, is a nutrient critical to many bodily functions, including nerve health, protein metabolism and blood sugar regulation. Because vitamin B6 is also vital to brain development, it’s important during pregnancy and infancy. It’s often promoted to help boost energy, as well as relieve stress.

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

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

“People might be surprised, the number of places B vitamins occur,” she said.

That’s part of the problem.

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

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

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

Poisoning is rare, although incidences are rising. Nationwide, 439 cases of vitamin B6 exposure were reported in 2024, none of which was fatal, up from 369 in 2019 and 311 in 2014, National Poison Data System records show.

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 tissue, water-soluble vitamins are released in the urine and therefore must be consumed regularly.

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

B6 toxicity may be underreported because symptoms build gradually and consumers may not be aware they’re getting too much. “It sneaks up on you,” said Latov, estimating that 5% to 10% of patients with neuropathy at the Weill Cornell center have high levels of B6.

Early signs are occasional numbness in the toes, which might be ignored, followed by the sensation of heat, cold, stinging or tingling that starts in the feet and can move up the leg, Latov said.

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

A blood test can determine if levels of B6 are excessive.

“There’s a pretty big margin of safety for B6, which means you can take a decent amount over the recommended dose and still be fine,” Alan said. “But anything at a high enough dose is going to have bad 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, began using an electrolyte drink mix in December of that year. She said she consumed the product once daily as directed, mixing one packet with 16 ounces of water. The label said each packet contains 1.93 mg, or 110% of the recommended daily amount, of vitamin B6.

Right away, Huddy said she began experiencing unexplained symptoms of vertigo, heart palpitations and adrenaline surges. Unaware of a possible link, she kept using the electrolyte packets. By January 2025, she also was having seasonal allergy-like symptoms and soon after 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’d never before had an allergic reaction to food and said doctors couldn’t explain it.

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

After she got out of the hospital, Huddy developed peripheral neuropathy, an umbrella term for diseases affecting the nervous system outside the brain and spinal cord, and tinnitus.

“I kept going back to the doctor just over and over and over and was like, ‘something is really wrong,’” Huddy said, adding that she was told her symptoms were a figment of her generalized anxiety disorder. “I kept getting dismissed and kept getting sent home.”

In May, Huddy said she begged a doctor to run 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 it is that you’re taking that has B6 in it, you need to stop.’”

What’s a safe amount of vitamin B6?

The recommended daily requirement of B6 ranges from 1.3 mg for younger adults to 1.5 mg for women over 50 and 1.7 mg for older men.

Vitamin B6-rich foods include poultry, fish, beef liver and other organ meats, potatoes and other starchy vegetables, and noncitrus fruits. Most people get enough from their diet, experts say.

The U.S. has a relatively high upper limit of vitamin B6 for adults: 100 mg. The European Food Safety Authority, for example, 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, established its own supplemental B6 upper limit of 100 mg per day. This is the amount that can be safely consumed by the general healthy population, said Andrea Wong, the group’s senior vice president and chief science 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 ability to process the vitamin,” Wong said, later adding, “There are so many other factors that can contribute to whatever potential effect you’re having.”

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

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

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

Vitamin B6 can remain in the body for 30 to 40 days. If you stop taking it, symptoms should get better, Latov said, although “depending on how much damage, the nerves may not regenerate completely.”

Huddy attributes her poisoning to the electrolyte drink mix, which she consumed daily for six months. She doubts her diet was a factor and said she didn’t take other supplements.

She continues to recover, although she has some lingering tinnitus and is in physical therapy for nerve issues. She’s resumed working and taken on another, unofficial job: providing support for others with vitamin B6 toxicity.

“I wish that I had somebody who could walk me through it the way that I’m now able to walk other people through it,” Huddy said.