FOR IMMEDIATE RELEASE
Orthomolecular Medicine News Service, August 27, 2025

Vitamin B6 Lawsuits in Australia: Science, Safety, and the Truth Behind the Headlines

by Richard Z. Cheng, M.D., Ph.D
Editor-in-Chief, Orthomolecular Medicine News Service

Editor's Note - OMNS receives many thoughtful reader questions, but our current platform doesn't support public Q&A. To foster more dialogue, I'll share selected letters and replies on my Substack (👉 https://substack.com/@rzchengmd). OMNS will continue publishing articles from our editors and authors; this Substack Q&A is simply a complementary channel. I hope OMNS will add interactive features in the future so all editors can join the conversation. - Richard Z. Cheng, M.D., Ph.D., Editor-in-Chief

Summary - Recent headlines from Australia report lawsuits alleging nerve damage from vitamin B6 supplements. Understandably, this has sparked public concern: If vitamin B6 (pyridoxine) is essential for life, how can it also be accused of causing serious harm? And could these cases be used to further restrict public access to this vital nutrient?

What's missing in these situations is not the value of supplementation itself - nutrient therapy remains a critical tool for health - but the way it is applied. In integrative orthomolecular medicine (IOM), no nutrient should be ever used as a stand-alone intervention. B6, like any vitamin or mineral, is prescribed in the context of the whole person: paired with essential cofactors, integrated with dietary and lifestyle measures, adjusted for individual biochemistry, and monitored for both safety and effectiveness. When supplementation is isolated from this broader IOM framework, its benefits can be reduced, and the risk of side effects increases - a gap that conventional guidelines and unsupervised use too often overlook.

1. What Is Vitamin B6 and Why Do We Need It?

Vitamin B6 is crucial for:

• 🧠 Neurotransmitter synthesis - serotonin, dopamine, GABA (1,2)
• 🍽 Amino acid metabolism - energy and brain chemistry (1)
• 🛡 Immune function - supporting antibody production (3)
• 🧬 Gene regulation - via one-carbon metabolism (4)
• ❤️ Homocysteine control - with B12 and folate (5)

Deficiency can lead to depression, irritability, fatigue, poor immunity, cracked lips, and-in severe cases-anemia or seizures (1).

2. Why Is B6 Linked to Toxicity in the News?

Peripheral neuropathy (nerve damage) from B6 supplementation has been documented- but typically in cases of:

• High-dose pyridoxine HCl >200-500 mg/day for many months or years (6,7)
• Missing key nutrient cofactors (magnesium, B2, B12, folate)
• Underlying metabolism issues that impair conversion of pyridoxine to its active form P5P (8,9)

Key points:

• Most cases are reversible after stopping supplementation (6)
• Active P5P form appears to have a lower risk profile (8)
• The U.S. NIH Upper Limit is set at 100 mg/day (1), yet many clinical protocols use 50-200 mg/day safely under supervision (10,11)

3. Vitamin B6 Toxicity: Mechanisms

To better understand the controversy, it is important to review the biological mechanisms by which excessive B6 can rarely cause harm:

• Dose and Duration - Most cases involve long-term intake of pyridoxine hydrochloride at >200-500 mg/day for months or years (6,7).
• Impaired Conversion to P5P - Pyridoxine must be converted in the liver to its active form, pyridoxal-5'-phosphate (P5P). When conversion is impaired (due to genetic variants, liver detox stress, or toxins), unmetabolized pyridoxine may accumulate and act as a functional antagonist, blocking active B6 pathways (8,9).
• Cofactor Deficiencies as Amplifiers - Low magnesium, riboflavin (B2), B12, or folate can impair pyridoxine utilization, amplifying the risk of neuropathy (8,12).
• Reversibility - In most reported cases, symptoms improve or resolve after discontinuation of high-dose supplementation. Persistent neuropathy is rare and usually linked to extremely high or hidden intakes (6,8).

👉 These mechanisms reinforce the orthomolecular principle: nutrients like B6 should never be used in isolation, but rather in synergy with cofactors, tailored to individual biochemistry, and monitored for both safety and benefit.

4. Other Factors That May Increase B6 Sensitivity

Even moderate doses can cause problems if certain conditions are present:

• Poor diet - high in carbs, ultra-processed foods, and low in protein (1,3).
• Chronic toxin exposure - Environmental toxins (e.g., heavy metals, pesticides, solvents) and certain medications (e.g., isoniazid, hydralazine) (13).
• Deficiency of other B-vitamins - Low B2 (riboflavin) or B12 (8,9).
• Low magnesium or zinc (8,12).
• Liver detox impairment (9).
• Genetic variants.

Integrative orthomolecular practice always considers these co-factors-addressing them can both reduce toxicity risk and maximize therapeutic benefit from B6.

5. The Australian Lawsuits - What We Know

Media reports suggest long-term use of B6 before neuropathy symptoms.

However:

• Doses, forms, and co-nutrient context are not disclosed
• Literature shows dose and form are critical to safety (6,7)
• In orthomolecular practice, unsupervised high-dose pyridoxine without cofactors is poor practice

6. Australia's Regulatory Climate

The Therapeutic Goods Administration (TGA) already has some of the world's strictest supplement rules.

• Since 2022, warning labels are required on products with >10 mg/day B6, claiming neuropathy can occur even below 50 mg/day (14).
• In 2025, the TGA proposed making products with 50-200 mg/day "pharmacist-only" (14,15).

This approach ignores decades of safe clinical use and individualized dosing principles. The risk is that lawsuits may push regulators toward even tighter restrictions, reducing access to safe, effective nutrient therapy.

7. Real-World Cases: Lessons from Australia

Prof. Ian Brighthope, my colleague on the OMNS editorial board, recently highlighted a striking case of vitamin B6 toxicity in Australia. Dr. Mary Buchanan, a general practitioner, developed progressive muscle weakness and peripheral neuropathy after unknowingly consuming excess B6 from over-the-counter magnesium tablets.

"I couldn't walk - 100 metres was a struggle," she recounted. Even a year after stopping, her recovery has been slow and incomplete.

➡️ Read Prof. Bright hope's article here

This case illustrates two key issues Prof. Brighthope has emphasized:

1. Hidden intake sources - B6 is found not only in supplements but also in energy drinks, cereals, and weight-loss shakes, leading to cumulative exposure well beyond safe levels.
2. Regulatory response - Australia's Therapeutic Goods Administration (TGA) has mandated warning labels for products with >10 mg/day of B6, after recognizing that neuropathy has been reported even at lower intakes when multiple products are combined.

8. Integrative Orthomolecular Medicine's Perspective

In IOM, B6 is:

• Personalized - Based on genetics, diet, symptoms (10).
• Synergistic - Always paired with magnesium, B2, B12, folate, zinc (8,10).
• Lifestyle-integrated - Supported by low-carb, nutrient-dense diet, toxin reduction, exercise, hormone balance.
• Clinically monitored - Doses above 50-100 mg/day used only with follow-up for symptoms or labs (1,10).

9. Hormones and B6 Need.

Thyroid, adrenal, and sex hormones can change how your body uses B6:

• Thyroid hormones - B6 intake can influence thyroid function; supplementation may lower high TSH in hypothyroidism (16).
• Adrenal hormones - Corticosteroids may increase B6 needs (17-19).
• Sex hormones - Estrogens may compete with B6; adequate B6 supports progesterone and testosterone synthesis (20).

10. Facts vs. Myths

✅ Facts

• Toxicity is rare and dose-dependent (6,8)
• Active P5P form is better tolerated (8)
• Most cases reverse after stopping (6)

🚫 Myths

• "Any dose above the RDA is dangerous" - false
• "All B6 forms are equally risky" - false
• "B6 toxicity is always permanent" - false

11. Safe Supplementation Guidelines

Always pair B6 with magnesium, B2, B12, folate, and zinc for optimal effect (8,10)

12. Bottom Line

Vitamin B6 is an essential nutrient and, when used wisely, a safe and powerful health tool. The Australian lawsuits highlight a need for better education on form, dose, and synergy - not fear-driven restrictions that may deny people access to safe, effective therapy.

About the Author

Richard Z. Cheng, M.D., Ph.D. - Editor-in-Chief, Orthomolecular Medicine News Service

Dr. Cheng is a U.S.-based, NIH-trained, board-certified physician specializing in integrative cancer therapy, orthomolecular medicine, functional & anti-aging medicine. He maintains active practices in both the United States and China.

A Fellow of the American Academy of Anti-Aging Medicine and a Hall of Fame inductee of the International Society for Orthomolecular Medicine, Dr. Cheng is a leading advocate for nutrition-based, root-cause health strategies. He also serves as an expert reviewer for the South Carolina Board of Medical Examiners, and co-founded both the China Low Carb Medicine Alliance and the Society of International Metabolic Oncology.

Dr. Cheng offers online Integrative Orthomolecular Medicine consultation services.

📰 Follow his latest insights on Substack: https://substack.com/@rzchengmd

References

1. Office of Dietary Supplements - Vitamin B6 [Internet]. [cited 2025 Aug 9]. Available from: https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/

2. Kennedy DO. B Vitamins and the Brain: Mechanisms, Dose and Efficacy--A Review. Nutrients. 2016 Jan 27;8(2):68.

3. Wintergerst ES, Maggini S, Hornig DH. Contribution of selected vitamins and trace elements to immune function. Ann Nutr Metab. 2007;51(4):301-23.

4. Finkelstein JD. Methionine metabolism in mammals. J Nutr Biochem. 1990 May;1(5):228-37.

5. Malinow MR, Bostom AG, Krauss RM. Homocyst(e)ine, diet, and cardiovascular diseases: a statement for healthcare professionals from the Nutrition Committee, American Heart Association. Circulation. 1999 Jan 5;99(1):178-82.

6. Dalton K, Dalton MJ. Characteristics of pyridoxine overdose neuropathy syndrome. Acta Neurol Scand. 1987 July;76(1):8-11.

7. Albin RL, Albers JW, Greenberg HS, Townsend JB, Lynn RB, Burke JM, et al. Acute sensory neuropathy-neuronopathy from pyridoxine overdose. Neurology. 1987 Nov;37(11):1729-32.

8. Schellack N, Yotsombut K, Sabet A, Nafach J, Hiew FL, Kulkantrakorn K. Expert Consensus on Vitamin B6 Therapeutic Use for Patients: Guidance on Safe Dosage, Duration and Clinical Management. Drug Healthc Patient Saf. 2025 Apr 7;17:97-108.

9. Hadtstein F, Vrolijk M. Vitamin B-6-Induced Neuropathy: Exploring the Mechanisms of Pyridoxine Toxicity. Adv Nutr. 2021 Oct 1;12(5):1911-29.

10. Brush MG, Bennett T, Hansen K. Pyridoxine in the treatment of premenstrual syndrome: a retrospective survey in 630 patients. Br J Clin Pract. 1988 Nov;42(11):448-52.

11. Ellis JM, Folkers K. Clinical aspects of treatment of carpal tunnel syndrome with vitamin B6. Ann N Y Acad Sci. 1990;585:302-20.

12. Gröber U, Schmidt J, Kisters K. Magnesium in Prevention and Therapy. Nutrients. 2015 Sept 23;7(9):8199-226.

13. Parry GJ, Bredesen DE. Sensory neuropathy with low-dose pyridoxine. Neurology. 1985 Oct;35(10):1466-8.

14. Administration (TGA) TG. Peripheral neuropathy with supplementary vitamin B6 (pyridoxine) | Therapeutic Goods Administration (TGA) [Internet]. Therapeutic Goods Administration (TGA); 2022 [cited 2025 Aug 9]. Available from: https://www.tga.gov.au/news/safety-updates/peripheral-neuropathy-supplementary-vitamin-b6-pyridoxine

15. NewsGP [Internet]. [cited 2025 Aug 9]. newsGP - Sweeping vitamin B6 restrictions proposed. Available from: https://www1.racgp.org.au/newsgp/clinical/sweeping-vitamin-b6-restrictions-proposed

16. Li L, Wang J, Chen J. Relationship between vitamin B6 intake and thyroid function in US adults: NHANES 2007-2012 results. PLoS One. 2025;20(4):e0321688.

17. Chang HY, Tzen JTC, Lin SJ, Wu YT, Chiang EPI. Long-term prednisolone treatments increase bioactive vitamin B6 synthesis in vivo. J Pharmacol Exp Ther. 2011 Apr;337(1):102-9.

18. Mahuren JD, Dubeski PL, Cook NJ, Schaefer AL, Coburn SP. Adrenocorticotropic hormone increases hydrolysis of B-6 vitamers in swine adrenal glands. J Nutr. 1999 Oct;129(10):1905-8.

19. Allgood VE, Powell-Oliver FE, Cidlowski JA. The influence of vitamin B6 on the structure and function of the glucocorticoid receptor. Ann N Y Acad Sci. 1990;585:452-65.

20. Rose DP. The interactions between vitamin B6 and hormones. Vitam Horm. 1978;36:53-99.

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Ian Brighthope, MBBS, FACNEM (Australia)
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