Vitamin B6 is essential for human health, yet its potential for harm at high and/or prolonged supplemental doses has long been underestimated.

The TGA's decision is a welcome step, but as the change won’t come into effect until 1 June 2027, there needs to be more effort to raise awareness about the risk of B6 supplements among health professionals and the Australian public.

Beyond B6 vitamins, there is a bigger question about the safety of complementary medicines when taken without any guidance from healthcare professionals.

Vitamin B6 is an essential nutrient for humans because, although it is required for numerous biological reactions, our bodies cannot make it, so we need to get it from external sources. Usually, this is through the diet, but it can also be obtained from tablets/supplements.

Today’s news isn’t that surprising. The TGA has required all supplements containing daily doses of more than 50 milligrams of Vitamin B6 to carry a warning statement since 2020. The threshold was lowered to 10 milligrams in 2022 as the TGA was concerned about a lack of public awareness regarding the dangers of excessive B6 intake. Other countries, such as the UK, have had similar rules for some time.

The problem is that vitamin B6 is in a range of products, so it is easy to accidentally take too much without realising. People may then not link their symptoms to the supplements, so they can be ill for some time and not know why.

The issue of vitamin B6 toxicity illustrates an important point - you can have too much of a good thing; everything is toxic in the right amount. Just because a certain amount of a substance might be good for us does not mean that larger amounts are better. The dose makes the benefit as well as the poison.

The Therapeutic Goods Administration (TGA) has moved to reduce access to vitamin B6 in some products in order to reduce the chances of harm. While the general public may think that because vitamins are essential to health, they are very safe, unfortunately, some vitamins cause harm at high concentrations. The tragic tale of Antarctic explorer Douglas Mawson and vitamin A toxicity is an example that should be familiar to all Australians.

The body uses vitamin B6 in many ways, including amino acid metabolism, glucose metabolism, lipid metabolism, and haemoglobin synthesis. It is important for normal brain development. However, too much vitamin B6 can cause a number of adverse effects, with a condition called peripheral neuropathy being of major concern. Peripheral neuropathy can involve numbness and tingling, difficulty in walking, pain and loss of coordination.

Dietary intake of vitamin B6 will not cause toxicity. Vitamin B6 toxicity occurs from overdosing on supplements or therapeutic vitamins. There are many supplements that contain vitamin B6; some supplements for stress may contain vitamin B6 levels well above the recommended daily intake, and long-term intake results in toxicity. The 2023 recommended upper limit of intake from the European Food Safety Authority is 12 mg/day for adults. The TGA currently requires all vitamin B6-containing listed medications with a recommended daily dose >10 mg to include a paraesthesia (numbness and tingling) warning. However, this has not been enough to stop the increasing reports of toxicity. While peripheral neuropathy can be reversed by stopping the supplements, it can also be permanent.

Importantly, many supplements contain Vitamin B6 (eg some magnesium supplements), so people may be exposed to cumulative toxic doses of vitamin B6. Some also may use the chemical names of Vitamin B6 (pyridoxine or pyridoxal), so it may not be clear that the supplement contains Vitamin B6. As well, vitamin B6 can also be found in products such as energy drinks, breakfast cereals, or weight loss shakes. So there is significant potential for overdose.

With rising reports of peripheral neuropathy, the TGA has moved to reduce exposure to vitamin B6. Now consumers require a pharmacist's supervision to purchase products containing more than 50mg of vitamin B6, and anything with more than 200mg will need a prescription. This is in line with other products (paracetamol packs containing more than 50 tablets, for example, are required to be purchased from behind the counter in a pharmacy, for example). Product labelling has also been targeted to provide consumers with clearer information.

The TGA is taking the right decision with regard to supply and access of B6. This vitamin is included in many different types of supplements, and it is too easy for consumers to inadvertently exceed the recommended daily dose. Changing the labelling requirements, and upscheduling high doses of vitamin B6, shows in the strongest terms that the TGA’s priority is patient safety.

This is a move in the right direction. The majority of people do not need vitamin B6 supplementation and obtain enough key nutrients, including B6 from their diet (from the likes of cereals, fruits and vegetables).

Some people need higher doses of Vitamin B6 (for example, to treat nausea and vomiting in pregnancy or children with epilepsy), however, additional oversight by a pharmacist is important to ensure that the vitamin B6 doesn’t interact with other medicines, vitamins or supplements that they are already taking.

Many people who purchase multivitamins and supplements do not know that the product contains vitamin B6 because of the different names that it goes by, and so they are at risk of taking too high a dose. Unknowingly combining products that contain already high doses of vitamin B6 puts the person at very high risk of adverse effects such as potentially long-lasting peripheral neuropathy, nerve damage and muscle weakness.

Pharmacists are well-positioned to assist people in understanding both the benefits of taking vitamin B6 and the risks associated with its use, especially at higher doses or over the long term.

High-dose vitamin B6 supplements have become popular, but are they really safe? 

The recommended dietary intake for a healthy adult is 1.3-1.7 mg/day. Vitamin B6 deficiency is more likely to occur in the elderly, or those with alcohol dependence, obesity, or certain kidney, liver and autoimmune conditions. However, vitamin B6 deficiency is uncommon among the Australian population.

Unlike other water-soluble vitamins, pyridoxine (the common form of vitamin B6) can accumulate in the body and cause irreversible damage. Recent evidence suggests that taking large amounts of pyridoxine can interfere with nerve function, causing symptoms like tingling, burning, and numbness. These effects can appear even at moderate doses in some people. Due to the widespread availability, some patients have been unknowingly taking excessive amounts from different combination products.

If you choose supplements, stick to low-dose options like multivitamins or B-complex products that provide less than 10mg per day. Always check labels and consult a healthcare professional before starting any high-dose regimen. For patient usage duration of longer than six months, and over 50 mg/day vitamin B6, regular monitoring by healthcare professionals is recommended. Screening for history of vitamin consumption is key to early detection of adverse events.

Other than supplementation, most people can meet their B6 needs through food. Salmon, chicken, potatoes, and chickpeas are excellent sources. Toxicity from food is extremely rare.

The bottom line: High-dose vitamin B6 is not risk-free. Safer strategies include focusing on food sources and keeping doses low.

The decision was expected, as the only substantive thing changed from what has been put out was the date of implementation. However, it did recognise B6 as being safe when used appropriately and the primary issue was people duplicating doses across multiple products. So, it does show a real need for increased education, not just to the public, but to practitioners as well.

The recommended daily dose is there to stop deficiency, but therapeutic doses can be much higher and for some people this is appropriate. But this is based on individual needs and should be discussed with a practitioner familiar with clinical nutrition.

Natural medicines can be powerful when used properly, but like any medicine can cause issues if used incorrectly. Some can be good but more is not always better.

Another thing to note is that there is another ongoing review by NHMRC to identify a safe lower dose. The allowed dose is likely to change based on this (IMO probably higher, but perhaps limited to some conditions.

It is a great relief that the TGA have finally taken this step to restrict public access to high-dose vitamin B6 in all its forms. After all, the toxicity of vitamin B6 has been known for over 30 years, so it is about time the TGA took steps to protect the public. It's just a shame that this ruling won't come into effect until June 2027.

This decision has been a long time coming, as the UK has regulated Vitamin B6 in doses > 50mg as a prescription drug since 1997. In the meantime, thousands of Australians have unwittingly consumed high doses of B6, either from individual products or multiple products with doses that accumulate to an overdose, and doctors were largely unaware that B6 could even BE toxic. Thankfully, doctors are now more aware; they know what the vitamin B6 toxidrome looks like and can diagnose it more quickly and accurately.  

New mandated warnings on the packaging of products containing B6 will also help consumers make more informed choices about whether to take products with B6 or not. In reformulating their products, hopefully, vitamin and supplement manufacturers will remove pyridoxine from products where its benefit was questionable in the first place.  

As doses of B6 between 50mg -200mg per day will now be regulated as Schedule 3 Pharmacist Only Medicines, the TGA  should provide education to pharmacists so they can handle requests for vitamin B6 products safely and appropriately.