Momentous Magnesium L-Threonate is the cognition-and-sleep pick in our magnesium roundup (74/100), and priced on the number that matters it is the most expensive magnesium we scored. That number is the whole story. The front of the bottle advertises 2,000 mg (2 g) of branded Magtein, but that is compound weight; the elemental magnesium — the mineral your body actually counts — is only about 145 mg a serving, the least in our field. Price the thing on elemental milligrams and the premium is stark. We pulled Momentous’s published pricing, checked July 2026, and turned it into the numbers that matter: per serving, per year, and per 100 mg of elemental magnesium.
The cost, in one table
Momentous sells one product here — a 90-capsule bottle at three capsules a serving, so 30 servings, roughly a one-month supply — for about $49.95, one-time or on subscription. The monthly and yearly figures matter more than the sticker, and the elemental line at the bottom is the one that reframes all of them. Figures checked July 2026.
| Bottle price (90 capsules, 30 servings) | ~$49.95 | one-time or subscription |
|---|---|---|
| Cost per serving (3 capsules) | ~$1.67 | premium tier |
| Cost per month (~30 servings) | ~$50 | daily use |
| Cost per year (~365 servings) | ~$608 | about twelve bottles |
| Elemental magnesium per serving | ~145 mg | the least in our field |
| Cost per 100 mg elemental | ~$1.15 | vs ~$0.37 for a glycinate |
What that buys per elemental milligram
The number that reframes Momentous’s price is cost per elemental milligram, because that is the magnesium you actually absorb — not the compound weight on the front. At about $1.67 for ~145 mg elemental, you pay roughly $1.15 per 100 mg of elemental magnesium. Our best-value pick, Nature Made Magnesium Glycinate (87/100), delivers 200 mg elemental for about $0.73 a serving — roughly $0.37 per 100 mg, so more than double the value here, closer to three times. The budget route, Doctor’s Best (80/100), lands near $0.08 per 100 mg elemental at about $0.16 a serving — a fraction of Momentous per milligram. What the premium buys is real but narrow: branded Magtein L-threonate, the one magnesium form specifically marketed to cross into the brain, plus NSF Certified for Sport testing, the strongest credential in the category. What it does not buy is more magnesium — ~145 mg is the least elemental serving in our field, and well under the 350 mg supplemental upper limit besides. Whether that is worth about $608 a year is the honest question: if you specifically want the L-threonate cognition angle and understand the evidence is early, maybe; if you just want to get enough magnesium, a glycinate wins outright on elemental dose and cost. The alternatives page lays out the cheaper routes, and the thesis stays the same throughout: read elemental milligrams, not compound weight.
Frequently asked questions
How much does Momentous Magnesium L-Threonate cost per serving?
About $1.67 a serving, based on a ~$49.95 bottle of 90 capsules at three capsules a serving (30 servings), checked July 2026. That is premium — and the catch is that a serving delivers only about 145 mg of elemental magnesium, the least in our field, because the “2,000 mg” on the front is compound weight, not magnesium.
How much is Momentous Magnesium L-Threonate per month and per year?
At one 3-capsule serving a day it works out to about $50 a month and about $608 a year (roughly twelve bottles). A value glycinate like Nature Made runs closer to $22 a month for 200 mg of elemental magnesium a serving — more magnesium, for less.
Why does Momentous cost so much per milligram of magnesium?
Because you only get ~145 mg of elemental magnesium a serving. At ~$1.67 that is about $1.15 per 100 mg elemental — more than double a glycinate’s ~$0.37. You are paying for the branded Magtein L-threonate form and the NSF Certified for Sport testing, not for more magnesium.
Is Momentous Magnesium L-Threonate worth the premium?
For the L-threonate form specifically — the one marketed to cross into the brain for sleep and cognition — it is the best-made, best-tested version in our field, if you accept the evidence is early. As a way to simply get magnesium it is the expensive, low-elemental route; a glycinate is the better value.
Sources
- Momentous — official Magnesium L-Threonate product and pricing pages (branded Magtein; 2,000 mg compound per 3-capsule serving delivering ~145 mg elemental magnesium, disclosed in the Supplement Facts panel; NSF Certified for Sport per batch; ~$49.95 for 90 capsules / 30 servings). Checked July 2026. livemomentous.com
- The Ingredient Report — Momentous Magnesium L-Threonate review (74/100), the magnesium roundup, and scored context for Nature Made Glycinate (87/100) and Doctor’s Best (80/100). Checked July 2026.
- The Ingredient Report — magnesium glycinate ingredient page (elemental-vs-compound thesis; 350 mg supplemental upper limit; form and evidence notes). Accessed July 2026.
Update history
- July 17, 2026 — Page first published. Facts checked this date. Next check: August 2026.
Content is for informational purposes only and is not medical or financial advice. Medical disclaimer.