Supplement answers for Australians

This page hasn't been reviewed by a pharmacist yet. It's general information, not medical advice.

Short, sourced answers to common Australian supplement questions: upper limits, combinations, timing and TGA rules. General information only.

• Is it safe to take magnesium and zinc together?
  Can you take magnesium and zinc at the same time? What NIH ODS says about high-dose zinc and magnesium, and the Australian upper limits for each (general information).
• Vitamin B6 rules in Australia: what changes on 1 June 2027
  The TGA is rescheduling vitamin B6 from 1 June 2027: 50 mg or less stays general sale, over 50 mg up to 200 mg becomes Pharmacist Only, over 200 mg stays prescription. Sources inside.
• Best value vitamin D in Australia: how to compare cost per dose
  How to work out the real cost of a vitamin D supplement in Australia: cost per IU, µg vs IU conversion, and the 80 µg (3,200 IU) adult upper limit.
• How much vitamin D is too much in Australia?
  The Australian/NZ adult upper limit for vitamin D is 80 µg (3,200 IU) a day. What that means, how to convert µg to IU, and what healthdirect says about toxicity.
• How much magnesium is too much? The Australian upper limit
  The Australian/NZ adult upper limit for supplemental magnesium is 350 mg a day, and it does not include magnesium from food. What it means and where totals add up.
• How much zinc is too much? The Australian upper limit
  The Australian/NZ adult upper limit for zinc is 40 mg a day from all sources. Why long-term high zinc can lower copper, and how to total zinc across products.
• Can you take iron and calcium together?
  Calcium may reduce iron absorption, so experts suggest taking iron and calcium supplements at different times. NIH ODS evidence and Australian upper limits.
• Can you take magnesium with antibiotics?
  Magnesium can bind tetracycline and quinolone antibiotics. NIH ODS says to take these antibiotics at least 2 hours before or 4–6 hours after magnesium. General information.