Sleep supplements such as magnesium, glycine, ZMA and L-theanine have only small studies behind them, so see them as a possible extra once your sleep habits are sorted, not a fix for insomnia. Melatonin is a medicine in Australia, available on prescription or, for some adults aged 55 and over, from a pharmacist. Here is what the research shows, and when to see your GP instead.
Start with sleep habits
Most adults need 7 to 9 hours of sleep a night to feel refreshed (Sleep Health Foundation). healthdirect's tips cost nothing (healthdirect):
- Go to bed and wake up at about the same time every day.
- Limit caffeine to mornings, and cut back on alcohol.
- Keep screens out of the bedroom and switch off an hour before bed.
- Keep your bedroom quiet, dark and not too hot or cold.
- Exercise regularly, but not in the evening.
If you train after work, note that the Australian Institute of Sport (AIS) says caffeine can affect sleep even at low intakes and has a half-life of about 5 hours, so an evening pre-workout or fat burner is still active at bedtime (AIS).
Do sleep supplements work? The evidence at a glance
| Supplement | Amounts studied | What research found | Strength of evidence |
|---|---|---|---|
| Magnesium | Varied, in older adults | Fell asleep about 17 minutes sooner than with placebo | 3 small trials, low quality |
| Glycine | 3 g before bed | Felt more rested, fell asleep sooner in one study | 3 small studies, industry-linked |
| L-theanine | 50 to 900 mg a day across trials | Small gains in self-rated sleep | Many small trials, few on L-theanine alone |
| ZMA | About 30 mg zinc, 450 mg magnesium, 10 mg B6 | No sleep benefit in healthy men | 3 small 2024 trials |
So the benefits of sleep supplements are modest at best, and healthdirect notes there is little evidence on whether herbal sleep remedies work. A natural sleep aid still has doses and side effects. What are the best sleep supplements in Australia? There is no single best sleep aid: magnesium makes most sense if your diet is low in it, and glycine or L-theanine can be trialled one at a time.
Magnesium for sleep
A 2021 review found three small trials in 151 older adults. Those taking magnesium fell asleep about 17 minutes sooner than with placebo, but the trials were at moderate to high risk of bias and the evidence was low to very low quality (Mah and Pitre, 2021).
Check the elemental magnesium on the label, not the compound weight. The Australian upper level for magnesium from supplements is 350 mg a day for adults, and diarrhoea is usually the first sign of too much. When choosing sleep supplements for women or men, the main difference is daily need: the recommended intake is 310 to 320 mg for women and 400 to 420 mg for men, from food and supplements combined (NHMRC). Our magnesium guide explains the forms.
Glycine and L-theanine
Glycine for sleep. Three small Japanese studies gave 3 g before bed. People felt more rested, and in one study with overnight monitoring they fell asleep sooner (Inagawa, 2006; Yamadera, 2007; Bannai, 2012). The groups were tiny and several researchers worked for a glycine maker. More in our glycine guide.
L-theanine is an amino acid from tea. A 2025 meta-analysis of 19 trials found small improvements in self-rated sleep quality and time to fall asleep, but few studies tested L-theanine on its own (Bulman and colleagues, 2025). Trials have used 50 to 900 mg a day (Cotter and colleagues, 2026). In one 4-week trial, 30 healthy adults taking 200 mg a day reported better sleep scores than on placebo (Hidese and colleagues, 2019).
What is ZMA, and does it work?
ZMA stands for zinc magnesium aspartate, usually with vitamin B6. The ZMA labels we checked give about 30 mg zinc, 450 mg magnesium and 10 mg vitamin B6 per serve.
ZMA for sleep. Three 2024 trials in healthy men found ZMA before bed did not improve sleep, and in one it cut total sleep time by about half an hour (Gallagher, 2024; Edwards, Behav Sci 2024; Edwards, Nutrients 2024). The claimed ZMA benefits are not well supported.
Does ZMA boost testosterone? ZMA is marketed mostly to men, but it did not change testosterone in 14 men with enough zinc in their diet (Koehler, 2009), or hormones and strength over 8 weeks of training in 42 men (Wilborn, 2004). Low testosterone is diagnosed by a GP with a blood test.
Is ZMA safe? ZMA side effects come down to the doses. 450 mg of magnesium is above the 350 mg supplement upper level. 30 mg of zinc is under the 40 mg upper level for all sources, but extra zinc adds up, and too much over time lowers copper status (NHMRC zinc). For women, 30 mg is nearly four times the 8 mg daily target (14 mg for men). The TGA also warns vitamin B6 can cause nerve damage, and says total B6 from multivitamins, magnesium and zinc products should be checked (TGA).
ZMA vs magnesium. For sleep, plain magnesium glycinate keeps you within the upper level without zinc and B6 you may not need. That is why we do not rank a best ZMA in Australia. If you want a zinc and magnesium combination, ATP Science ZMAG gives 100 mg magnesium and 2.5 mg zinc per capsule, up to three a day, with no B6.
Melatonin in Australia
Melatonin is a medicine here, not a supplement. The TGA lists it as prescription only (Schedule 4), except modified-release tablets of 2 mg or less for adults aged 55 and over, in packs of up to 30, which are pharmacist only (Schedule 3) (TGA). Talk to your GP or pharmacist if you are considering it.
Sleep supplements for athletes
Athletes need two extra checks: keep caffeine out of the evening, and if you are drug tested, use batch-tested products. A Sport Integrity Australia survey found 35% of 200 supplements bought online contained a prohibited substance (Sport Integrity Australia), so look for a HASTA or Informed Sport mark.
When to see a GP
See your GP if poor sleep is affecting your mood or daytime life, or you often wake unrefreshed. healthdirect describes chronic insomnia as trouble falling or staying asleep at least 3 nights a week for at least 3 months, and says cognitive behaviour therapy (CBT) is usually the first approach to try. If you are pregnant, breastfeeding or on regular medicines, ask your GP or pharmacist before any sleep supplement.
Products to look at
How to take a sleep aid: start with one product at a time at the label dose, so you can tell whether it helps. There is no set amount of sleep supplements per day, so stay within each label and the upper levels above.
- Beast Labs Magnesium Bi-Glycinate 750mg: 150 mg elemental magnesium per capsule.
- Nature Best Magnesium Glycinate: 200 mg elemental magnesium per 2 capsules.
- NOW Foods Glycine 1000 mg: 3 g glycine per 3-capsule serve, the amount used in the studies.
- Best Naturals L-Theanine 200mg: 200 mg per tablet, 1 or 2 a day on the label.
- ATP Science ZMAG: 100 mg magnesium and 2.5 mg zinc per capsule. Not for use in pregnancy.
- Primabolics Everyday Sleep Restore: an evening drink with 1 g glycine, 200 mg L-theanine, magnesium and herbs including valerian and ashwagandha.
Browse our sleep support range and magnesium range. Some blends contain ashwagandha, covered in our ashwagandha guide. See also our post on sleep and recovery.
FAQs
Is melatonin over the counter in Australia?
Only in one narrow case. The TGA lists melatonin as a prescription medicine, except modified-release tablets of 2 mg or less for adults aged 55 and over, which a pharmacist can supply without a prescription. Everyone else needs a prescription. Talk to your GP or pharmacist if you are thinking about it.
What is ZMA and when should I take it?
ZMA is a mix of zinc, magnesium and vitamin B6. Most labels we checked give about 30 mg zinc, 450 mg magnesium and 10 mg B6 per daily serve, taken 30 to 60 minutes before bed, as in the studies. Take no more than one serve a day, and count any zinc, magnesium and B6 in your multivitamin or other products.
Are sleep supplements safe, and what are the side effects?
Sleep supplements are not risk-free, even at label doses. Too much magnesium from supplements causes diarrhoea, long-term high zinc can lower copper levels, and the TGA warns vitamin B6 can cause tingling or numbness in the hands or feet. Little is known about the long-term effects of herbal remedies. Check with your GP or pharmacist first if you are pregnant, breastfeeding, take regular medicines or have a medical condition.
How much magnesium should I take for sleep?
There is no set dose for sleep. The Australian upper level for magnesium from supplements is 350 mg a day for adults, so stay within that unless your doctor advises otherwise. Read the elemental magnesium on the label rather than the compound weight: a 750 mg magnesium glycinate capsule may give only 150 mg of magnesium. Adults need 310 to 420 mg a day from food and supplements combined.
Where can I buy sleep supplements in Australia?
You can buy sleep supplements, magnesium and ZMA-style formulas online at Supps247 with Australia-wide delivery, or visit one of 18 Supps247 stores, 17 in Victoria and one in Richlands, Queensland. Use the store locator to find a store near you. Stock varies between stores, so check the product page or call the store before you travel.
Sources: Sleep Health Foundation; healthdirect insomnia; healthdirect melatonin; TGA melatonin scheduling; TGA vitamin B6; AIS caffeine; NHMRC magnesium; NHMRC zinc; Mah and Pitre; Inagawa; Yamadera; Bannai; Bulman; Hidese; Cotter; Gallagher; Edwards (Behav Sci); Edwards (Nutrients); Koehler; Wilborn; Sport Integrity Australia; product labels.
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.
