Most adults can get enough zinc from food, and if you do use a supplement, a small daily dose is usually all you need. Men need 14 mg of zinc a day and women 8 mg from all sources, and the upper level is 40 mg a day from food and supplements combined (NHMRC). Below: zinc forms such as picolinate and glycinate, safe doses, zinc with magnesium, timing and nausea, and the evidence on immunity and testosterone.
How much zinc do you need? Zinc for men and women
The Nutrient Reference Values for Australia and New Zealand set these daily amounts for adults aged 19 and over:
| Group | Recommended daily intake | Upper level (all sources) |
|---|---|---|
| Men | 14 mg | 40 mg |
| Women | 8 mg | 40 mg |
| Pregnancy | 11 mg | 40 mg |
| Breastfeeding | 12 mg | 40 mg |
Zinc for women and zinc for men differ only in the daily target, not the safety ceiling. The NHMRC says vegetarians, particularly strict vegetarians, may need about 50% more, because plant foods contain phytates that bind zinc and reduce absorption (NIH ODS).
Bigger doses are not better. In a small absorption study, raising a single zinc dose above about 20 mg added relatively little extra absorbed zinc, with a predicted maximum of about 13 mg absorbed (Tran and colleagues, 2004).
Zinc forms: picolinate, glycinate, gluconate and citrate
Labels list elemental zinc, the amount of zinc itself rather than the weight of the whole compound (NIH ODS). The form changes absorption a little, but the evidence comes from small studies:
| Form | What the research shows |
|---|---|
| Zinc gluconate and citrate | About 61% absorbed, similar to each other (NIH ODS) |
| Zinc oxide | About 50% absorbed (NIH ODS) |
| Zinc picolinate | In a 1987 trial of 15 adults, hair, urine and red blood cell zinc rose with picolinate but not with citrate or gluconate |
| Zinc glycinate (bisglycinate) | In a 2007 single-dose study of 12 women, bioavailability was about 43% higher than gluconate |
Zinc glycinate and picolinate look slightly better absorbed, but these were small, short studies. For most people the dose, and taking it consistently, matters far more than the form.
Is zinc safe? Zinc side effects and how much is too much
Zinc is safe at sensible doses, but more is not better. The 40 mg upper level is based on the amount that starts to affect copper status (NIH ODS). The NIH lists these zinc side effects:
- Too much at once: nausea, dizziness, headaches, stomach upset, vomiting and loss of appetite.
- 50 mg or more for weeks: lower copper absorption, reduced immune function and lower HDL (good) cholesterol.
- Long-term excess: copper deficiency, which can lead to neurological problems.
Many single zinc products contain 30 to 50 mg per tablet. Add zinc from food and a multivitamin and you can pass 40 mg without noticing, which is why every product in this guide gives less than 25 mg of zinc per daily serve.
Zinc also interacts with some medicines. The NIH advises taking quinolone or tetracycline antibiotics at least 2 hours before or 4 to 6 hours after zinc, keeping zinc and penicillamine at least 1 hour apart, and notes that thiazide diuretics increase zinc loss in urine. If you take regular medication, are pregnant or have a medical condition, ask your GP or pharmacist first.
Zinc on an empty stomach, timing and nausea
There is a trade-off. Food, especially phytate-rich wholegrains and legumes, can lower zinc absorption (NIH ODS), so an empty stomach suits absorption. But nausea and stomach upset are listed side effects, and most zinc labels we checked say to take it with food or a meal.
- If zinc makes you feel sick, take it with a meal and check the dose. Nausea is linked to excess zinc, so a lower dose is often the simplest fix.
- Keep iron supplements apart: the NIH says 25 mg or more of iron taken at the same time can reduce zinc absorption.
- Pick a time you will remember and stick with it.
Zinc and magnesium together
Taking zinc and magnesium together is fine at normal doses. The NIH notes that only very high zinc intakes, around 142 mg a day from supplements, interfere with magnesium absorption. The bigger issue is the magnesium dose in some combination products.
Many ZMA-style products give 30 mg of zinc and 450 mg of magnesium per full serve. The upper level for magnesium from supplements is 350 mg a day, and diarrhoea is usually the first sign of too much (NIH ODS). ZMA products also contain vitamin B6, which the TGA says should be counted across all your supplements. Check the full serve against these limits before you buy.
A lower-dose option is ATP Science ZMAG, with 2.5 mg of zinc and 100 mg of magnesium per capsule, up to three a day (7.5 mg zinc and 300 mg magnesium in total). For more on magnesium types, read our magnesium guide.
Does zinc work? Immunity and testosterone claims explained
Immunity and colds. Zinc plays a role in the immune system, but a supplement is not a force field. A 2024 Cochrane review of 34 trials with 8,526 people found zinc appears to make little or no difference to whether you catch a cold, and may shorten a cold by about 2 days when taken after it starts. The review rated all of these findings as low or very low certainty.
Zinc for testosterone. Low zinc can lower testosterone. In a small 1996 study, young men on a zinc-restricted diet had a large drop in testosterone, and nine older men with marginal zinc deficiency saw it rise after 3 to 6 months of zinc. But when 14 exercising men who already ate enough zinc took a ZMA supplement, their total and free testosterone did not change (Koehler and colleagues, 2009). Zinc only helps testosterone if you are short of zinc. Low testosterone is diagnosed by a GP with a blood test (Healthy Male), so see your doctor about symptoms. More in our men over 40 guide.
Zinc for beginners: a simple checklist
- Add up the zinc in any multivitamin, ZMA or immune product you already take.
- Stay well under 40 mg a day from all sources. Daily needs are 8 mg for women and 14 mg for men.
- Choose a modest dose, under 25 mg a day, in a form you tolerate.
- Take it with food if it upsets your stomach, and away from iron supplements and some antibiotics.
- Vegetarians, vegans, pregnant women and anyone on medication should check with a GP, pharmacist or dietitian.
Products to look at
These in-stock products give less than 25 mg of zinc per daily serve. We checked each label in October 2026.
- ATP Science ZMAG: 2.5 mg zinc (as gluconate) and 100 mg magnesium per vegan capsule, maximum three a day. A listed medicine, AUST L 320575.
- Condemned Labz Multi: 11 mg zinc as glycinate chelate per 2-tablet serve.
- Beast Labs MultiVitamin: 11 mg zinc per 2-capsule serve.
- Biokey Multivitamin: 10 mg zinc as glycinate per 2-capsule serve. It also contains 4 mg of iron.
Compare more options in our best multivitamins guide and best magnesium supplements guide, or browse vitamins and minerals and immune health.
FAQs
What is the best zinc supplement in Australia?
There is no single best zinc supplement for everyone. A good choice gives a dose you actually need, usually well under 25 mg a day, in a form you tolerate, such as glycinate, picolinate, citrate or gluconate. Count the zinc in any multivitamin first and stay under the 40 mg daily upper level from all sources. If you are vegetarian, pregnant or on medication, ask your GP or pharmacist what suits you.
Where can I buy zinc online in Australia?
You can buy zinc online at Supps247 with Australia-wide delivery, which usually takes 2 to 8 business days, and free shipping on orders of $99.99 or more. You can also visit one of our 18 stores in Victoria and Queensland to compare labels with our team. Stock varies by store, so check the product page before you travel.
Is zinc glycinate better than other forms?
Zinc glycinate (bisglycinate) is a chelated form, and a small 2007 study of 12 women found it gave about 43% higher bioavailability than zinc gluconate after a single dose. Zinc picolinate also did well in a small 1987 trial. Because these studies are small, glycinate is a good option rather than a must. A sensible daily dose, taken consistently, matters more than the form.
Should I take zinc on an empty stomach?
You can, and food, especially wholegrains and legumes, can lower zinc absorption. But nausea and stomach upset are listed zinc side effects, so if zinc on an empty stomach makes you feel sick, take it with a meal, as most labels direct. Keep it away from iron supplements of 25 mg or more and from some antibiotics, as the NIH advises.
Can I take zinc and magnesium together?
Yes. The NIH says only very high zinc intakes, around 142 mg a day, interfere with magnesium absorption, so normal doses are fine together. Watch the totals instead: keep zinc under 40 mg a day from all sources and magnesium from supplements at or under 350 mg a day. Many ZMA products give 450 mg of magnesium per full serve, so read the label.
Does zinc increase testosterone?
Only if you are low in zinc. Research shows zinc restriction can lower testosterone and correcting a marginal deficiency can raise it, but a study of exercising men who already ate enough zinc found a ZMA supplement did not change their testosterone. Low testosterone is diagnosed by a GP with a blood test, so see your doctor if you have symptoms rather than guessing with supplements.
Sources: NHMRC Nutrient Reference Values, zinc; NIH Office of Dietary Supplements, zinc fact sheet; NIH Office of Dietary Supplements, magnesium fact sheet; Tran and colleagues (2004), zinc absorption by dose; Barrie and colleagues (1987), zinc picolinate, citrate and gluconate; Gandia and colleagues (2007), zinc bisglycinate vs gluconate; Cochrane review (2024), zinc and the common cold; Prasad and colleagues (1996), zinc status and testosterone; Koehler and colleagues (2009), ZMA and testosterone; Healthy Male, low testosterone; TGA, vitamin B6 safety update.
Order online with Australia-wide delivery, free on orders of $99.99 or more, or visit a Supps247 store in Melbourne, regional Victoria or Brisbane to compare products in person before you buy. Members can use our member price match on full-priced items.
Always read the label and follow the directions for use. If you have a medical condition, are pregnant or take regular medication, check with your doctor first.
