An analysis of pharmacy sales data reveals Australians could unknowingly be putting themselves at risk of vitamin B6 toxicity.
Warning labels and other regulatory changes have not stopped Australians from purchasing vitamin B6-containing products with doses that exceed recommended intake limits, leading researchers to call for other ways to prevent potential cases of neurological damage.
Over the last 25 years the Therapeutic Goods Administration has made several regulatory changes in how vitamin B6 products are labelled and sold in an attempt to reduce vitamin B6 toxicity, which can cause irreversible sensory neuropathy in some cases. The latest change came in November 2025, when the TGA announced that as of June 2027 all products with a daily vitamin B6 dose exceeding 50mg but less than 200mg will be rescheduled as Schedule 3 (pharmacist only) medicines.
However, knowledge about if and how such changes affect real-world purchasing behaviours is scarce. Consequently, Australian researchers sought to calculate how many vitamin B6 products are being sold, and how much vitamin B6 is being consumed each day by analysing pharmacy sales data from the IQVIA Consumer Health Basket Database between August 2022 and July 2025. This data source contained sales data from 4623 of 6215 community pharmacies across the country, representing roughly three quarters of national complementary medicines pharmacy sales data.
“This study demonstrates that high-risk vitamin B6 purchasing behaviours are widespread in Australian community pharmacies, with large volumes of products delivering doses about current recommended intake continuing to be purchased, including through cumulative exposure from multiple lower dose products,” the researchers wrote in the Internal Medicine Journal.
The researchers were specifically interested in 792 different products containing vitamin B6, at a maximum recommended daily oral dose of ≥5mg of pyridoxine. All products were a Listed or Registered Medicine on the ARTG at any point between August 2022 and July 2025.
More than 20 million vitamin B6-containing products were purchased across 15.8 million transactions over the three-year study window. The average number of products sold (6.8 million) and transactions (5.3) per year were consistent over this period.
Overall, products with 5-9mg accounted for 29.1% of sales, 10-24mg products for 26.3%, and 25-49mg products for 27.9%. The remaining products had maximum daily doses of 50mg or more.
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The proportion of products purchased decreased as the recommended daily dose increased; the researchers observed decreases in sales of products containing 5-9mg (from 2.04 million to 1.84 million), 50-99mg (1.05 million to 0.99 million), and ≥200mg (52.5 thousand to 3.3 thousand) of vitamin B6 over the three-year study window. However, there was an increase in the number of products containing 100-199mg (4.65 thousand to 9.54 thousand).
“This aligned with a change in Australian regulation in 2023 that reduced the maximum allowable pyridoxine dose from 200 to 100 mg, and hence a reduction in product availability,” the researchers wrote. “It suggests that consumers were shifting to purchase a product with the next highest dose available dose of pyridoxine.”
When considering the number of vitamin B6-containing products (and their combined total dosage of pyridoxine) that were purchased in each transaction, the researchers concluded that 21.6% of all transactions could be deemed as “high-risk”, as they may have meant consumers were taking ≥50mg of pyridoxine each day.
In addition, 644,000 of these “high-risk” transactions were flagged as more than one vitamin B6-containing product was being purchased. Most of these transactions were due to consumers purchasing two different products. Transactions where a consumer bought three different products typically resulted in a combined daily dose of 50-99mg, while transactions with four or more products resulted in a combined daily dose of 100-199mg.
Based on their findings, the researchers concluded that passive risk communication strategies that rely on product labels and/or general public advisories would have little effect on consumer behaviour.
“This is supported by the finding that the transaction-level analyses identified over one million higher-risk transactions annually involving combined daily doses ≥50mg, including multiple-product and duplicate purchases. These transactions represent scenarios with elevated potential for cumulative exposure over time,” they wrote.
The researchers felt that pharmacists could play a leading role in preventing excessive vitamin B6 intake, as more than 60% of complementary medicines sales occur in pharmacies.
“This gatekeeping function may be particularly valuable in identifying high-risk purchasing patterns and providing consumer education,” they wrote.
“However, any benefits from rescheduling are contingent on pharmacists being adequately supported within existing business models to provide risk-based counselling and to identify early symptoms of neurotoxicity, particularly in light of interindividual variability in susceptibility.
“While schedule 3 access creates opportunities for adverse drug reaction reporting during routine medication history assessment, these opportunities will only be realised if pharmacists receive appropriate education and system-level support.”
The research was limited by the sales data not including non-pharmacy retail platforms (e.g., supermarkets, health food stores, and medical clinics that sell complementary medicines) or compounded vitamin-B6 containing products that were dispensed from pharmacies.
“As a result, total vitamin B6 exposure may have been underestimated, and the findings should be considered a conservative estimate,” the researchers noted.
“However, this conservative estimate may be counterbalanced by the fact that individual consumer behaviour could not be assessed; it remains unclear whether products were purchased for personal use or shared among household members, and actual intake may differ from the maximum recommended dose.”
