A surge in health-conscious supplement use has brought a renewed warning about vitamin B6 toxicity, as fresh research and regulatory concern reveal that excessive intake may be harming more people than previously recognized. Australia’s medicines regulator, the Therapeutic Goods Administration (TGA), recently admitted it may have underestimated the scope of vitamin B6 side effects—especially nerve damage linked to prolonged high-dose use—prompting the body to reconsider how this over-the-counter supplement is sold (The Conversation).
Vitamin B6, or pyridoxine, is long established as vital for metabolism, brain function, immune support, and hemoglobin creation in red blood cells. Widely included in multivitamins and consumed for perceived benefits during pregnancy or to counter premenstrual syndrome, B6 appears benign when taken in modest amounts—just 1.3–1.7 mg daily is recommended for most adults. Typical Thai diets, rich in meats, cereals, fruits, and vegetables, already provide sufficient levels, negating widespread need for supplementation.
Yet, modern marketing and easy access to vitamins, particularly in pharmacies, supermarkets, and health food stores, mean many are self-medicating far beyond what the body needs. According to TGA data cited in a recent ABC Australia report, supplements offering anywhere from 5mg up to 200mg of vitamin B6 per dose are freely available without prescription, and doses exceeding that are obtainable by doctor’s order. Anecdotal and lab evidence now suggests harm—specifically, nerve damage—might develop at far lower doses and after shorter exposures than formerly thought.
Neuropathy, the main side effect highlighted by clinicians and regulators, refers to injury in nerves outside the brain or spinal cord. Typical symptoms include numbness or pain in the hands and feet, difficulty with balance or coordination stemming from muscle weakness, and even gastrointestinal discomfort like heartburn or nausea. Warning signs may take months or years to fade even after stopping the supplement, with some cases lingering for as long as two years.
Supporting this concern is new information from a pathology expert whose clinic facilitates B6 testing across Australia. Data from May revealed about 4.5% of blood samples tested returned levels “very likely” associated with nerve damage, signaling a troubling trend that could easily be mirrored among heavy supplement users in Thailand—especially as similar over-the-counter availability exists here.
Recent studies underscore the risk, with conflicting but significant data. For instance, a 1990s study following 70 people over five years who took 100–150mg daily found no neuropathy cases. However, more current reports, such as a 2023 case where a man taking 95mg daily across several products experienced nerve damage, illustrate the unpredictable danger even at doses under 100mg. Separate reports highlighted energy drinks fortified with vitamin B6 as a culprit, with at least seven cases of neuropathy attributed to these beverages. Australia’s TGA adverse events database registered a notable 174 cases linked to B6 since 2023 alone.
Given these findings, regulators in Australia are considering restricting non-pharmacy sales of high-dose forms, requiring pharmacist consultation before purchase. This follows a global trend: in Europe, authorities have set 25mg per day as an upper safe limit, while the US National Institutes of Health recommend caution with doses above 100mg per day, to avoid nerve risks (NIH Office of Dietary Supplements).
Perspectives from medical experts stress the importance of considering dietary sources and not exceeding supplement doses absent clear medical need. “Over-supplementation occurs because consumers often take multiple products without realising the combined effect,” said a clinical pharmacologist involved in the research. “Vitamin B6 doesn’t accumulate rapidly, but long-term daily excess can cause real, avoidable harm.”
In Thailand, supplement use is growing, fuelled by health trends, easy e-commerce access, and appeals to wellness during and after the Covid-19 pandemic. A public health official warns, “Like in Australia, Thais often perceive vitamins as universally safe. But the reality is more complex, especially for fat-soluble or neurologically active substances like vitamin B6.”
The Thai Food and Drug Administration (FDA) currently regulates supplements but often does not require prescriptions for levels under 100mg, mirroring the now-questioned Australian approach. This is especially concerning for populations at risk of high intake: elderly individuals layering multiple supplements, pregnant individuals prescribed B6 for morning sickness, and younger people consuming ’energy’ drinks or powders.
Culturally, vitamin use in Thailand is sometimes seen as a mark of affluence or health-seeking behaviour. “Many believe more is better,” notes a nutrition lecturer at a leading Thai university, “but with B6, more can be dangerous. As traditional Thai cuisine already supplies sufficient B6, supplementing without guidance is unnecessary for most people.”
The Conversation’s article details three symptoms to watch for in suspected B6 toxicity:
- Numbness or pain in hands and feet (indicative of peripheral neuropathy).
- Balance issues and poor coordination due to muscle weakness.
- Gastrointestinal discomfort, particularly heartburn and nausea.
Those experiencing such symptoms—especially if using high-dose vitamins or consuming multiple ‘fortified’ drinks—are advised to consult a doctor immediately and discontinue supplement use. “People wrongly assume excess vitamins are quickly removed by the body,” said a hospital-based dietician. “For B6, long-term high doses can leave a lasting imprint long after intake stops.”
Thai readers should note that standard diets already provide needed B6. Monitoring supplement intake, reading labels, and avoiding redundant products is crucial, especially for vulnerable groups such as the elderly, pregnant, or chronically ill. Families should be particularly wary of energy drinks marketed with health claims but containing hidden high doses of B6, as young Thais are increasingly drawn to these products.
Looking ahead, tighter regulation seems likely as international awareness grows. Thai regulators may follow Australia’s lead by restricting high-dose B6 sales or requiring pharmacist oversight. Public health education about dietary sufficiency and the reality of vitamin toxicity must keep pace with the popularity of supplements.
To protect your health, take these practical steps:
- Review whether you truly need vitamin supplements, especially B6, if you eat a balanced Thai diet.
- Avoid exceeding 50mg B6 daily for longer than six months, unless prescribed and supervised by a medical professional.
- Be wary of energy drinks and multiple supplements with overlapping vitamin B6 content.
- Seek medical advice if experiencing numbness, weakness, or gastrointestinal symptoms while using vitamin supplements.
- Monitor regulatory updates from the Thai Food and Drug Administration for new guidance, and always consult a pharmacist before adding any high-dose supplement to your diet.
For those interested in further detail, referenced sources include articles from The Conversation, NIH Office of Dietary Supplements, and reporting from ABC News Australia.