Last updated: October 4, 2026 · Originally published: September 10, 2026 · By Eternal Elixir Editorial
Magnesium L-threonate benefits with human-trial support fall into two groups: memory and thinking speed, and how rested people feel the next day. For sleep itself the evidence splits. One trial found better deep and REM sleep scores on a sleep-tracking ring, and a larger Perth trial found no change on the same ring but better daytime effects of sleep.
That split is the most useful thing to know before you buy magnesium threonate for sleep. This guide covers the four human trials, how the form works and what has only been shown in rats, how it compares with magnesium glycinate for sleep, what it costs per serve in Australia, and who should not take it.
Key takeaways
- In a six-week Perth trial of 100 adults with unsatisfying sleep, 2 g a day of magnesium L-threonate improved overall cognition, working and episodic memory and reaction time against placebo.
- Sleep results split: an American trial of 80 adults found better ring-measured deep and REM sleep scores on 1 g a day, while the Perth trial found no ring-measured sleep changes but lower overnight heart rate and better daytime effects of sleep.
- We found no trial that compares threonate and glycinate head to head for sleep. Glycinate has one placebo-controlled sleep trial with a small benefit, and threonate has two with mixed results.
- A 2,000 mg serve supplies about 144 mg of elemental magnesium, well under the 350 mg a day upper level for supplemental magnesium.
- Our Magnesium L-Threonate 2000mg is three capsules a serve, 90 capsules for $59.99, which is $2.00 a day.
Eternal Elixir makes Magnesium L-Threonate 2000mg, and it is our pick because each three-capsule serve delivers the 2,000 mg amount used in the Perth trial, in vegetable capsules with nothing else added.
Magnesium L-Threonate Benefits: What the Human Trials Show
Every magnesium form supplies the same mineral. What sets magnesium L-threonate apart is its research: it is the form with placebo-controlled human trials built around memory, thinking and next-day function, where most other forms were studied for general magnesium intake. Four trials carry most of the evidence.
| Trial | Who took part | Daily dose | Length | Main result |
|---|---|---|---|---|
| Liu, 2016 (USA) | 44 adults aged 50 to 70 with memory complaints, poor sleep and anxiety, and below-norm scores on a thinking test | 1.5 g or 2 g by body weight (MMFS-01) | 12 weeks | Overall cognitive ability improved against placebo. Sleep effects could not be judged because of a strong placebo response |
| Zhang, 2022 (China) | 109 healthy adults aged 18 to 65 | 2 g of a formula with magnesium L-threonate, phosphatidylserine and vitamins C and D | 30 days | Better scores than placebo on all five parts of a standard memory test. Older participants improved more |
| Hausenblas, 2024 (USA) | 80 adults aged 35 to 55 with self-reported sleep problems | 1 g, two hours before bed | 21 days | Better ring-measured deep and REM sleep scores, plus better mood, energy and alertness on waking |
| Lopresti, 2026 (Perth) | 100 adults aged 18 to 45 with unsatisfying sleep | 2 g | 6 weeks | Better overall cognition, memory and reaction time. Better daytime effects of sleep. No ring-measured sleep changes, but lower overnight heart rate and higher heart rate variability |
Memory and thinking: the 2026 Perth trial
The newest trial is Australian. Adrian Lopresti and Stephen Smith at Clinical Research Australia in Perth gave 100 adults aged 18 to 45, all unhappy with their sleep, either 2 g a day of magnesium L-threonate (as Magtein) or a placebo for six weeks (Lopresti and Smith, 2026).
The magnesium group improved more than placebo on the NIH Toolbox total cognition score (p = 0.043), with the largest effects on working memory and episodic memory. Reaction time improved too (p = 0.031), and the authors reported a 7.5-year drop in estimated brain cognitive age. Scores on Raven’s matrices, a reasoning test rather than a memory test, did not change (p = 0.953). Threotech, the company behind Magtein, funded the trial and supplied the product.
A formula trial in healthy Chinese adults
Zhang and colleagues at Nanjing Medical University gave 109 healthy adults aged 18 to 65 either 2 g a day of a Magtein-based formula or a starch placebo for 30 days (Zhang et al., 2022). The formula group beat placebo on all five parts of a standard memory test and on the overall memory score, and older participants gained more than younger ones. The formula also contained phosphatidylserine and vitamins C and D, so this trial cannot isolate the magnesium.
Older adults with memory complaints: the MMFS-01 trial
The earliest human trial came from Guosong Liu and colleagues at Neurocentria, the company that developed the formula (Liu et al., 2016). They recruited 44 adults aged 50 to 70 with memory complaints, poor sleep and anxiety, whose scores on a thinking test were below age norms. Participants took 1.5 g or 2 g a day by body weight, or a placebo, for 12 weeks. Overall cognitive ability improved against placebo (p = 0.003), with the biggest change in executive function.
The part most articles skip is the authors’ own caveat. Sleep and anxiety improved so much on placebo that the trial could not say whether magnesium L-threonate changed them. If you have seen this study cited as proof that the form helps sleep, that citation goes further than the paper.
Magnesium Threonate and Sleep: Where the Evidence Splits
Two trials measured sleep with both questionnaires and an Oura ring, and they did not agree.
The 2024 trial: better deep and REM sleep scores
Heather Hausenblas and colleagues gave 80 adults aged 35 to 55 with self-reported sleep problems either 1 g a day of Magtein, about 75 mg of elemental magnesium, or a placebo, taken two hours before bed for 21 days (Hausenblas et al., 2024). On the ring, deep sleep and REM sleep scores improved against placebo, along with several activity and readiness scores. On questionnaires, the magnesium group reported better behaviour on waking, more energy and daytime productivity, less grouchiness and better mood and alertness. Four adverse events were logged on magnesium and 13 on placebo. Three of the six authors work for AIDP, a supplement ingredient company.
The 2026 Perth trial: calmer nights, no change in sleep stages
The Perth cognition trial above also tracked sleep, and its results were more mixed.
| Sleep measure (2026 Perth trial) | How it was measured | Result against placebo |
|---|---|---|
| Sleep-related impairment (how poor sleep affects the day) | Questionnaire | Improved (p = 0.043) |
| Sleep disturbance, whole group | Questionnaire | No difference (p = 0.316) |
| Sleep disturbance, worse sleepers only | Questionnaire, subgroup | Improved (p = 0.031) |
| Restorative sleep | Questionnaire | No difference (p = 0.439) |
| Sleep outcomes such as stages and duration | Oura ring | No group differences |
| Resting heart rate during sleep | Oura ring | Greater reduction (p = 0.030) |
| Heart rate variability during sleep | Oura ring | Greater increase (p = 0.036) |
Read together, the picture is consistent enough. The clearest overnight signals in Perth were a lower resting heart rate and higher heart rate variability, which the authors describe as markers of lower stress and better autonomic balance. People also felt less held back by their sleep during the day. What did not move in Perth was sleep time or sleep stages on the ring, and the authors concluded that the form improved some subjective measures of sleep but not objective ones.
So set expectations accordingly. If you want to be knocked out at 10 pm, this is the wrong product. If you want a calmer night and a clearer next morning, that matches what the trials measured. Our guide to magnesium L-threonate for sleep, with dose and timing goes further into the evening routine.
Add Magnesium L-Threonate 2000mg to cart · $59.99How Magnesium L-Threonate Works, and What Was Only Shown in Rats
Magnesium sits at the NMDA receptor, a synapse closely tied to learning and memory. The difficulty is getting it there. Raising blood magnesium does not reliably raise magnesium inside the brain, because the blood-brain barrier controls what crosses.
Magnesium L-threonate was designed around that problem. It pairs magnesium with L-threonate, a vitamin C metabolite. In 2010, Slutsky and colleagues reported in Neuron that it raised brain magnesium in rats and improved their learning and memory, with more synapses in the memory centres of the brain (Slutsky et al., 2010).
Two caveats belong next to that finding. It was a rat study, and rat brain-magnesium readings do not transfer straight to people. The human trials above measured memory tests, questionnaires and wearables, not brain magnesium. The mechanism is plausible and the human cognitive results are real, but the link between them is still partly inferred. Our roundup of the best nootropic supplements in Australia sorts the rest of the category by the same evidence standard, and our Australian nootropics guide explains how we weigh measured outcomes against felt ones.
One more practical detail: magnesium L-threonate carries less elemental magnesium than most forms, because the threonate carrier takes up much of the weight. Our label puts it at about 144 mg of elemental magnesium per 2,000 mg serve, roughly 7% by weight.
Is Magnesium L-Threonate Better Than Glycinate for Sleep?
Nobody can say yet, because we found no trial that compares them head to head. Glycinate has one placebo-controlled sleep trial, and threonate has the two described above.
The glycinate trial ran in Germany in 2025. It gave 155 adults aged 18 to 65 with self-reported poor sleep either magnesium bisglycinate supplying 250 mg of elemental magnesium a day or a placebo for four weeks (Schuster et al., 2025). Sleep-difficulty scores fell further on glycinate than on placebo (p = 0.049), but the effect was small, and other psychological measures did not differ. People who ate less magnesium in their diet seemed to benefit more.
That points to a sensible way to choose. Glycinate delivers more elemental magnesium per serve, so it suits someone whose main aim is to raise a low magnesium intake. Threonate delivers less, but it is the form with trials on memory, next-day function and overnight heart rate. The table sets the common forms side by side.
| Form | Human evidence most relevant to sleep and the brain | Elemental magnesium | Best fit |
|---|---|---|---|
| Magnesium L-threonate | Memory, reaction time and next-day function in placebo-controlled trials. Mixed sleep results | Low: about 144 mg per 2,000 mg serve | Next-day clarity and a calmer night |
| Magnesium bisglycinate | One four-week sleep trial with a small benefit | Higher: the sleep trial used 250 mg a day | Raising total magnesium intake with a gentle form |
| Magnesium citrate | Absorbed well in small studies | Higher than threonate | General top-up |
| Magnesium oxide | Absorbed less completely than citrate in small studies | Higher than threonate | Low-cost bulk magnesium where absorption matters less |
The absorption comparison for citrate and oxide comes from the NIH Office of Dietary Supplements magnesium fact sheet. If you already take a magnesium product for general intake, threonate does a different job and does not replace it. Our comparison of the best magnesium supplements in Australia sets the forms side by side on elemental dose and price.
Magnesium L-Threonate in Australia: Prices Compared (as of Sep 2026)
Magnesium L-threonate is dosed in grams, so compare products on cost per 2,000 mg serve, not per capsule or per bottle. These are the products we could check in Australia and on iHerb AU. We took each price, pack and serve from the seller’s own page in September 2026.
| Product | Where to buy | Price (AUD, as of Sep 2026) | Pack | Serve (label) | Cost per serve | Buy |
|---|---|---|---|---|---|---|
| Eternal Elixir Magnesium L-Threonate 2000mg (our pick) | eternalelixir.com.au, ships from Sydney | $59.99 | 90 vegetable capsules, 30 serves | 3 capsules: 2,000 mg, about 144 mg elemental | $2.00 | View product |
| Switch Nutrition Mag3 | switchnutrition.com.au | $49.95 | Powder, 30 serves | 1 heaped scoop: 2,000 mg Magtein, 144 mg elemental | $1.67 | Switch Nutrition |
| Source Naturals Magtein | iHerb AU | $106.52 | 180 gelatin capsules, 60 serves | 3 capsules: 2 g Magtein, 147 mg elemental | $1.78 | iHerb |
| Life Extension Neuro-Mag | iHerb AU | $57.23 | 90 vegetarian capsules, 30 serves | 3 capsules: 2,000 mg Magtein, 144 mg elemental | $1.91 | iHerb |
| Sports Research Magtein | iHerb AU | $61.10 | 90 veggie capsules, 30 serves | 3 capsules: 2,000 mg Magtein, 144 mg elemental | $2.04 | iHerb |
| Apollo Nutraceuticals Magnesium L-Threonate | Elite Supps | $69.90 | 90 capsules, 30 serves | 3 capsules: 2,000 mg plus 100 mg L-theanine and 50 mg apigenin | $2.33 | Elite Supps |
Who each one suits, and who it doesn’t
- Eternal Elixir Magnesium L-Threonate 2000mg (our pick). Suits anyone who wants the full 2,000 mg serve in vegan capsules with no added actives, shipped from Sydney. Multi-bottle orders bring it to $1.70 a serve for three bottles and $1.60 for five. It does not suit someone who wants the lowest single-order price per serve, which belongs to Switch Nutrition’s powder.
- Switch Nutrition Mag3. Suits people happy to scoop a powder, and it has the lowest cost per serve in the table on a single order. It does not suit anyone who wants capsules, and its free shipping starts at $150.
- Source Naturals Magtein. Suits iHerb shoppers who want a two-month bottle. Its label suggests starting at one capsule and working up. It does not suit vegans, because the capsules are gelatin.
- Life Extension Neuro-Mag. Suits iHerb shoppers who want Magtein at a lower price per serve than ours. It does not suit anyone who wants to buy from an Australian seller.
- Sports Research Magtein. Suits iHerb shoppers who want Magtein in veggie capsules. It costs slightly more per serve than ours.
- Apollo Nutraceuticals. Suits someone who wants L-theanine and apigenin in the same capsules. It does not suit anyone who wants magnesium on its own, and it is the dearest per serve here.
For pharmacy options, we covered magnesium threonate at Chemist Warehouse separately, and our best magnesium L-threonate comparison for Australia has more brands.
Eternal Elixir Magnesium L-Threonate 2000mg: What Is in the Bottle
We make one magnesium product, and it is this one. The facts from the label and product page:
- Magnesium L-threonate, 2,000 mg per three-capsule serve, about 144 mg of elemental magnesium.
- 90 capsules per bottle, which is 30 serves.
- The only other ingredients are rice flour and a vegetable capsule, so it suits vegans and vegetarians.
- Take three capsules a day with a meal: all three in the evening for sleep, or two in the morning and one in the evening for focus.
- $59.99 a bottle, or $2.00 a serve. Two bottles cost $107.98 (10% off), three cost $152.97 (15% off), and five save 20%.
- Ships from Sydney within 24 hours, with free shipping over $100, a 30-day money-back guarantee and Afterpay.
The serve matches the 2,000 mg used in the Perth cognition trial, and one bottle covers most of its six weeks. Two bottles cover the full six weeks and clear the free-shipping line.
Add Magnesium L-Threonate 2000mg to cart · $59.99Dosage, Timing and How Long to Give It
| Goal | Daily amount | Timing | Trial length to match |
|---|---|---|---|
| Sleep and evening wind-down | 2,000 mg (3 capsules) | All three with your evening meal. The 2024 trial dosed two hours before bed | 21 days |
| Memory and focus | 2,000 mg (3 capsules) | Two in the morning, one in the evening | 6 weeks |
| New to magnesium supplements | Start with 1 capsule and build up | With food | Build to the full serve over a week or two |
The trials ran for three, six and twelve weeks, so judge it after six weeks rather than after a weekend. Take it at the same time each day, and take it with food if your stomach is sensitive. The same patience applies to the better-evidenced picks in our guide to energy supplements in Australia.
Pairing it for sleep
For the evening, our standardised saffron extract is the pairing we suggest. Saffron has its own set of placebo-controlled sleep trials, three of them run in Perth, covered in our guide to saffron for sleep. Magnesium and Saffron Extract 30mg together come to $109.98, which clears the $100 free-shipping line.
For the daytime, keep energising products in the morning. Our Korean Red Panax Ginseng is a morning product, and our breakdown of Korean red panax ginseng for energy, focus and stress explains where it fits.
Side Effects, Downsides and Who Should Not Take It
Magnesium L-threonate was well tolerated in the trials. The Perth trial reported no significant adverse reactions, and the 2024 trial logged fewer adverse events on magnesium than on placebo. Excess supplemental magnesium usually shows up first as diarrhoea, which can come with nausea and cramping, and this is why Australia’s upper level for magnesium from supplements is 350 mg a day for adults (Nutrient Reference Values). One serve of ours supplies about 144 mg.
The real downsides are practical ones:
- Price per milligram of magnesium. You pay more per milligram of elemental magnesium than with glycinate or citrate, because you are paying for the form rather than the amount.
- It will not cover a low intake alone. The recommended dietary intake for adults is 400 to 420 mg a day for men and 310 to 320 mg for women, from food and supplements combined, and 144 mg covers only part of that.
- The evidence is young. Four human trials exist, and companies with a stake in the ingredient funded or co-wrote at least three of them.
Talk to your doctor or pharmacist before taking it if any of these apply:
- You have reduced kidney function, since the kidneys clear excess magnesium and toxicity risk rises when they work less well.
- You take antibiotics of the tetracycline or quinolone type. The usual advice is to take them at least 2 hours before or 4 to 6 hours after a magnesium supplement.
- You take bisphosphonates for bone health. Keep magnesium at least 2 hours away from them.
- You take diuretics or long-term stomach-acid medicines, which change how the body handles magnesium.
- You are pregnant or breastfeeding. Our label says not to use it then unless your doctor advises it.
- You are under 18. Our product is intended for adults.
The interaction advice comes from the NIH Office of Dietary Supplements. For more detail, read our guide to magnesium L-threonate side effects. If you also take another magnesium product, add up the elemental amounts across both before you stack them.
Frequently Asked Questions
Can magnesium threonate help sleep?
Possibly, in a limited way. In a 21-day trial of 80 adults, 1 g a day improved deep and REM sleep scores on a sleep-tracking ring against placebo. In a six-week Perth trial of 100 adults, 2 g a day did not change ring-measured sleep but lowered overnight heart rate and reduced how much poor sleep affected the day. Expect a calmer night and a clearer morning rather than a sedative effect.
Add Magnesium L-Threonate 2000mg to cart · $59.99
Is magnesium L-threonate better than glycinate for sleep?
We found no trial that compares them directly. Glycinate has one four-week sleep trial with a small benefit at 250 mg of elemental magnesium a day. Threonate has two sleep trials with mixed results, plus trials on memory and next-day function. Choose glycinate to raise a low magnesium intake, and threonate if next-day clarity is the goal.
Is there a downside to taking magnesium L-threonate?
The main downsides are cost and dose. It costs more per milligram of elemental magnesium than other forms, and a 2,000 mg serve supplies only about 144 mg of magnesium. The trials reported it as well tolerated, and loose stools are the usual sign that total magnesium from supplements is too high.
Who should not take magnesium L-threonate?
People with reduced kidney function should not take any magnesium supplement without medical advice. Anyone taking tetracycline or quinolone antibiotics, bisphosphonates or diuretics should check timing with a pharmacist. Our label says not to use it while pregnant or breastfeeding unless your doctor advises it, and it is intended for adults.
What happens if you take magnesium threonate every day?
Daily use is how it was studied: every trial used continuous daily dosing for three to twelve weeks, and it was well tolerated. Expect nothing dramatic in the first week. The measured changes appeared over weeks.
How long does magnesium L-threonate take to work?
Plan on three to six weeks. The sleep trial measured its results at 21 days, and the Perth cognition trial measured its results at six weeks. The older-adult trial ran for twelve weeks.
Can you take magnesium L-threonate with other magnesium supplements?
Generally yes, if you add up the elemental magnesium across every product rather than counting bottles. A 2,000 mg serve of magnesium L-threonate gives about 144 mg of elemental magnesium, so it sits comfortably alongside a modest glycinate dose for most adults. If you notice loose stools, your combined total is too high, so cut the higher-dose product first.
What is the best magnesium L-threonate supplement in Australia?
Our pick is Eternal Elixir Magnesium L-Threonate 2000mg, which we make. It gives the full 2,000 mg serve in three vegan capsules, 90 capsules for $59.99, and ships from Sydney within 24 hours. Switch Nutrition’s Mag3 powder has the lowest single-order price per serve we found, and our magnesium L-threonate guide for Australia covers dose and evidence in more depth.
Add Magnesium L-Threonate 2000mg to cart · $59.99
The Bottom Line
Magnesium L-threonate is the magnesium form with trials built around memory and next-day function. At 2 g a day for six weeks it improved memory and reaction time in Perth. Its sleep results are mixed: better ring-measured deep and REM sleep scores in one trial, and a calmer overnight heart rate with better daytime effects of sleep in another. If that is what you are after, choose a product that gives the full 2,000 mg serve and give it six weeks. Ours does that for $2.00 a day, and you can see the rest of our range in the Eternal Elixir shop.
Sources
- Lopresti AL, Smith SJ. The effects of magnesium L-threonate (Magtein) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial. Front Nutr. 2026;12:1729164. PubMed 41601871
- Hausenblas HA, Lynch T, Hooper S, et al. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial. Sleep Med X. 2024;8:100121. PubMed 39252819
- Zhang C, Hu Q, Li S, et al. A Magtein, magnesium L-threonate, -based formula improves brain cognitive functions in healthy Chinese adults. Nutrients. 2022;14(24):5235. PubMed 36558392
- Liu G, Weinger JG, Lu ZL, et al. Efficacy and safety of MMFS-01, a synapse density enhancer, for treating cognitive impairment in older adults: a randomized, double-blind, placebo-controlled trial. J Alzheimers Dis. 2016;49(4):971-990. PubMed 26519439
- Slutsky I, Abumaria N, Wu LJ, et al. Enhancement of learning and memory by elevating brain magnesium. Neuron. 2010;65(2):165-177. PubMed 20152124
- Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep. 2025;17:2027-2040. PubMed 40918053
- Nutrient Reference Values for Australia and New Zealand: magnesium. eatforhealth.gov.au
- NIH Office of Dietary Supplements. Magnesium: fact sheet for health professionals. ods.od.nih.gov
- Product labels and prices: Eternal Elixir Magnesium L-Threonate 2000mg, Switch Nutrition Mag3, Source Naturals, Life Extension, Sports Research and Apollo Nutraceuticals, checked September 2026.
