Magnesium L-threonate: what you are actually paying for
Published September 1, 2026. This page argues a position. Every other page on this site computes its answer from data and does not.
Run and checked by Dan, a registered nurse who trains and uses these supplements. Every figure names its source, and links to it where the source is public. About this site. Not medical advice.
Magnesium L-threonate is the most expensive way to buy magnesium that we track, by a distance. Per 200 mg of elemental magnesium the L-threonates we track cost $1.36 to $2.30, about 11 to 18 times the $0.125 of the cheapest glycinate whose panel names a single magnesium salt. That is not a small premium for a nicer bottle. It is a different order of price.
Part of that gap is not marketing. It is on the label, and almost nobody looks at it.
About 7% of it is magnesium
The Momentous panel prints both figures, which is more than most brands do: “Magnesium (from 2 g Magtein Magnesium L-Threonate) 145 mg.” Two grams of compound carrying 145 mg of the mineral. So roughly 7% of what you swallow is magnesium, and the other 93% is the molecule carrying it.
That is much of the cost structure in one line. To get a given amount of magnesium you buy and swallow around fourteen times its weight in compound, and that compound is a patented branded ingredient rather than a commodity salt. A dose is 4.1 capsules against 1.5 capsules for that glycinate. The price follows the chemistry.
None of that is a criticism yet. If the molecule does something the others do not, a high price per milligram of magnesium is beside the point, because magnesium per se is not what you would be buying. The computed comparison is here, and which magnesium products a certifier names at their exact package is on which magnesium supplements are third party tested.
What the evidence actually tested
There is a real randomized, double-blind, placebo-controlled trial, published in Frontiers in Nutrition: 100 adults aged 18–45 with self-reported poor sleep, 2 g of Magtein daily for six weeks, primary outcome the NIH Total Cognition Composite. It reported improvements in cognitive performance, memory, reaction time and subjective sleep. That is a better evidence base than most supplements have, and it should be said plainly.
Two things about it matter for the decision you are actually making.
The comparator was placebo (rice flour), not cheaper magnesium. So the trial can support “Magtein beat nothing.” It cannot support “Magtein beat glycinate,” because glycinate was never in the study. The question a buyer faces at the shelf is the second one, and it has not been tested. A trial against placebo is the right first study to run and the wrong one to cite when choosing between two products.
It was funded by Threotech Inc., which also supplied the product, and the lead author's research company discloses funding from nutraceutical companies. That does not make the result wrong, and industry funds most supplement research, but a single industry-funded trial with no active comparator is a thinner basis for a 11 to 18× premium than the confidence around this form suggests.
Worth noticing too: the trial delivered 145 mg of elemental magnesium a day, roughly a third of the adult Daily Value. Whatever it demonstrates, it is not a study of meeting your magnesium needs.
There is no head-to-head trial, and the cheap form has evidence too
I went looking for a study comparing L-threonate against another magnesium form. As far as I can find, none exists. Every trial on either side is against placebo. So the comparative claim, that this form does something the cheaper ones do not, has not been tested by anyone, in either direction.
What I did find is that magnesium bisglycinate has its own randomized, placebo-controlled trial, and on the numbers it is the sturdier of the two:
| L-threonate | Bisglycinate | |
|---|---|---|
| Participants | 100 | 155 |
| Duration | 6 weeks | 4 weeks |
| Elemental magnesium | 145 mg | 250 mg |
| Comparator | placebo (rice flour) | placebo (cellulose) |
| Funded by | Threotech Inc., which supplied the product | Leibniz University Hannover |
The bisglycinate trial is larger, uses more magnesium, and was funded by a university rather than by the company selling the ingredient. It also reports itself more soberly: a statistically significant but small improvement in insomnia severity, Cohen's d of 0.2. The threonate coverage, by contrast, led with a “7.5-year reduction in brain cognitive age”, which is a surrogate measure and a much more arresting sentence.
So the picture is not “the expensive form has science and the cheap one does not”. Both have been shown to beat a placebo. Neither has been shown to beat the other. And the trial behind the expensive form is the smaller one, paid for by the company that owns the ingredient.
On the podcast effect
This form is popular well beyond what one trial would ordinarily produce, and the reason is that it is discussed constantly by high-reach podcasters and creators in the sleep and cognition space. That is an observation about attention, not an accusation: the people recommending it generally believe it, and some of them describe the evidence more carefully than the brands do.
What I would actually say
Not that L-threonate is a scam. The mechanism is plausible, the trial is real, and if you have tried cheaper forms and found this one works better for your sleep, that experience is worth more to you than any table on this site.
What I would say is narrower: the evidence does not answer the question you are asking when you pay 11 to 18×. That question is “is this better than glycinate,” and the study that gets cited compared it to rice flour. If you are buying it for magnesium, you are paying a very large premium for a small amount of it. If you are buying it for the threonate specifically, you are making a bet on a mechanism, and it is worth knowing that is what you are doing.
If cost is your primary concern, a reasonable middle is to try the cheap form first for a month. A month of the glycinate above, at the site's 200 mg yardstick, is about $3.75. If it does nothing and threonate does, you have learned something about yourself that no trial can tell you, and you will not have paid the premium to find out.
Sources
- Supplement Facts panel for Momentous Magnesium L-Threonate: the 145 mg / 2 g figure and the 4.1 capsules per dose are read from it and computed on the product page.
- Lopresti et al., “The effects of magnesium L-threonate (Magtein) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial”, Frontiers in Nutrition. Full text. Funding, comparator and dose are stated in the paper.
- Magnesium bisglycinate in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Full text. 155 randomized, 250 mg elemental magnesium daily, funded by the Institute of Food and One Health, Leibniz University Hannover.
- Updated September 14, 2026: the price figures are now computed from current prices, against the cheapest glycinate whose panel names a single magnesium salt. From September 1 this note said “46 times”, measured against a powder whose own panel names both magnesium glycinate and magnesium oxide, and before a cheaper L-threonate was added.
- No trial comparing L-threonate against another magnesium form was found when this was written on September 1, 2026. If one exists, or appears later, the corrections page is how to tell us, and it would change the argument above rather than decorate it.
Prices quoted are the cheapest we track and move; the category page has the current figures. If you think this piece is wrong, the corrections page says how to tell us.
What this rests on: prices we last recorded at the retailer named on each product page, which go stale, and each page says when it was checked; the products we track, not every product sold, and Amazon and Walmart are not among the stores; listings and labels read at the source, each linked from the page. Found an error? Tell us. The full method: How we compare.