A rise in self-directed supplementation has sparked fresh concerns about vitamin B6 toxicity. New research and regulatory scrutiny suggest that excess intake may cause nerve damage at lower doses and shorter exposures than previously understood. Australia’s Therapeutic Goods Administration signals it may have underestimated adverse effects, prompting tighter scrutiny of high-dose B6 products. This reflects a growing global move toward cautious use of over-the-counter vitamins.
Vitamin B6, or pyridoxine, supports metabolism, brain function, immune health, and red blood cell formation. It is common in multivitamins and is often taken during pregnancy or to ease premenstrual symptoms. For most adults, daily needs are roughly 1.3 to 1.7 mg. In Thailand, typical diets provide ample B6 from meat, grains, fruits, and vegetables, reducing the perceived need for extra supplementation.
Yet aggressive marketing and easy access mean many people self-medicate beyond what their bodies require. Regulators point to high-dose formulations from 5 mg to 200 mg per dose that are readily available without prescription, with higher doses obtainable through medical supervision. Emerging evidence indicates nerve damage can occur at lower levels and with shorter exposure than once thought.
Neuropathy, the primary concern cited by clinicians, involves nerve injury outside the brain and spinal cord. Symptoms include numbness or tingling in the hands and feet, balance problems, and sometimes heartburn or nausea. In some instances, these symptoms persist for months or years after stopping the supplement.
Pathology centers performing B6 testing report a noteworthy share of results associated with nerve damage. Data from May show about 4.5% of results are “very likely” linked to neuropathy risk. This signals a potential public health issue, especially where high-dose B6 is popular.
Research offers a nuanced picture. Older studies found no neuropathy in small groups taking 100–150 mg daily over several years, while more recent reports describe nerve damage in people taking around 95 mg daily for weeks or months. There have also been cases tied to energy drinks fortified with vitamin B6. Australia’s adverse events database shows hundreds of B6-related issues since 2023.
Regulators are considering limits on non-pharmacy sales of high-dose B6 and may require pharmacist consultation before purchase. This aligns with a broader international approach: Europe has a 25 mg per day safe limit, while the United States cautions against daily intakes above 100 mg.
Medical experts urge considering dietary sources and avoiding supplements unless there is a clear medical reason. A clinical pharmacologist notes that many people take multiple products, inadvertently increasing total intake. Vitamin B6 does not accumulate rapidly, but long-term excess can cause real harm.
In Thailand, supplement use is rising with health trends and online shopping, reinforced by wellness habits developed during and after the Covid-19 era. Public health officials warn that Thais often assume vitamins are universally safe, but this is not the case for substances like B6 that can affect nerves.
Thai regulators, including the Food and Drug Administration, regulate supplements but often do not require prescriptions for levels under 100 mg. This stance raises concern for vulnerable groups—older adults using multiple products, pregnant individuals prescribed B6 for morning sickness, and younger consumers seeking energy-boosting drinks or powders.
Culturally, vitamins are sometimes seen as a sign of affluence or proactive health behavior. A nutrition expert from a leading Thai university cautions that “more is not always better.” With Thai cuisine typically providing sufficient B6, unnecessary supplementation is common only when guidance is lacking.
Three warning symptoms to watch for, summarized for readers, are:
- Numbness or pain in hands and feet, signaling peripheral neuropathy.
- Balance difficulties and coordination issues due to muscle weakness.
- Gastrointestinal discomfort, including heartburn and nausea.
If you notice these signs while taking high-dose vitamins or multiple fortified products, seek medical advice promptly and stop the supplements. A hospital-based dietitian stresses that excess vitamins are not quickly flushed from the body and can leave lasting effects if intake remains high over time.
Practical guidance for Thais:
- Reassess the need for vitamin supplements, especially B6, if your diet is balanced.
- Avoid taking more than 50 mg of B6 daily for extended periods unless supervised by a clinician.
- Be cautious of energy drinks and multiple supplements with overlapping B6 content.
- Consult a healthcare professional if you develop numbness, weakness, or digestive symptoms while taking vitamins.
- Stay informed about regulatory updates from the Thai FDA and consult a pharmacist before adding high-dose supplements.
For those seeking more detail, recent discussions emphasize prudent use and awareness of potential nerve-related risks, drawing on insights from health research groups and regulatory bodies.