Vitamin B6 toxicity can cause nerve damage, with cases emerging from supplement stacking, according to neurologist Dr. Baibing Chen. He said that taking too much vitamin B6 can damage sensory neurons, leading to peripheral neuropathy. Symptoms include numbness, tingling, burning, pain, and balance problems. Dr. Chen noted that toxicity typically results from cumulative intake over time, not a single large dose.
Water-soluble vitamins are not always safe despite being excreted in urine, Dr. Chen said. He also warned that fat-soluble vitamins A, D, E, and K can build up in the body and become toxic. "A lot of people think that because vitamins are natural and you can get them over the counter, they can't cause you any harm, but that's not completely true," Dr. Chen said. He added that even water-soluble vitamins like B and C are not always harmless.
These three supplements were sold and recommended by Australian pharmacies to 'support' my 'health'. My doctor told me to stop taking the vitamins immediately after looking at my blood test results. He said that they were probably making my symptoms worse.
Specific supplement products contain high levels of vitamin B6, far exceeding the recommended daily intake of 1.1mg to 1.3mg for an adult. Blackmores Mega B Complex contains 50mg of vitamin B6, while Swisse's Zinc+ contains 30mg. Blackmores Super Magnesium+ contains approximately 29 times the recommended daily intake. Dr. Chen described a young patient who developed neuropathy from stacking multiple supplements containing B6, including multivitamins, energy drinks, an anti-stress supplement, and a sleep supplement. "The biggest issue is not someone taking a massive dose at once, but it's rather stacking," he said.
Patients were advised to stop supplements after blood tests revealed toxicity. According to Daily Mail - News, Jessica Amir described being severely unwell since February 2025, struggling to walk and losing the ability to write her name. She had been taking Blackmores Mega B Complex, Swisse's Zinc+, and Hair, Skin & Nails together. Her doctor told her to stop the supplements after blood test results. She is part of a class action investigation against Blackmores. Dominic Noonan-O'Keeffe developed B6 toxicity after taking Blackmores Super Magnesium+ and Ashwagandha+. He said he stopped all supplements immediately, got a blood test, and within a week received a diagnosis of B6 toxicity. He expressed hope for recovery but noted that the prospects are unknown.
I've been severely unwell since February 2025. I went from training for an 80 kilometre run, to struggling to walk two metres. I lost the ability to write my own name. I couldn't work for five months. My speech became slurred. My arms and legs were weak, numb, tingling and burning. I had constant pressure in my head. My vision became blurry. I lost my balance. I was walking into things.
I stopped all of my supplements straight away, got a blood test, and within a week, I had a diagnosis of B6 toxicity.
I'm hoping I'm at the tail end of a big flare-up, and this is the start of recovery, even though we know the recovery prospects are pretty unknown.