Best Magnesium L-Threonate Supplements 2026: Cost per Effective Dose
The lowest-cost magnesium L-threonate is Double Wood Magnesium L-Threonate, $1.03 a day at its list price. Both products we track use the same Magtein ingredient and give the same 144 mg of magnesium a serving, so price is the main difference: $1.03 to $1.67 a day. For everyday magnesium, L-threonate costs about 4 times as much per mg as our glycinate pick at list price.
Lowest cost for magnesium L-threonate
Double Wood Magnesium L-Threonate
2,000 mg of Magtein (144 mg of magnesium) in 4 capsules, $1.03 a day at Double Wood’s list price for one 120-capsule bottle. Same ingredient and dose as NOW, for less, and it is on NSF/ANSI 173, which checks that the capsule holds what the label says.
Check price on Amazon- Want the NOW brand? NOW Magtein Magnesium L-Threonate gives the same 144 mg in 3 capsules, $1.67 a day at list price.
- Want magnesium for sleep or everyday use, not memory? Revive MD Pure Magnesium Glycinate 200 mg, our overall pick: 200 mg in 2 capsules, on the Informed Sport list, $0.33 a day. Why it is our pick.
All magnesium L-threonate supplements compared
The 2 we track, ranked by what one 144 mg serving costs at each brand’s own list price, cheapest first. Amazon’s price can differ.
| Product and size | A serving | Per 300 mg | A year |
|---|---|---|---|
| 1 Double Wood Magnesium L-Threonate 120-capsule bottle, list $30.95, 144 mg magnesium in 4 capsules (30 servings)On NSF/ANSI 173 | $1.03 | $2.15 | $377 |
| 2 NOW Magtein Magnesium L-Threonate 90-capsule bottle, list $49.99, 144 mg magnesium in 3 capsules (30 servings)No testing list found · score 4.5/10 | $1.67 | $3.47 | $608 |
The score (out of 10) weighs testing, dose, cost, label and recalls, and compares L-threonates with each other only. None gives a full dose of magnesium in one serving (144 mg), which lowers each one’s dose mark. How we score.
| Item | Value |
|---|---|
| Double Wood Magnesium L-Threonate | $2.15 |
| NOW Magtein Magnesium L-Threonate | $3.47 |
| Revive MD Pure Magnesium Glycinate 200 mg | $0.50 |
Is one L-threonate better than another?
Not on what is inside. Both list “Magtein,” the trademarked magnesium L-threonate, at 2,000 mg a serving, giving 144 mg of magnesium. Both brands buy the same trademarked ingredient. What differs:
- Capsules a serving: 4 for Double Wood and 3 for NOW. Same dose; Double Wood takes one more capsule.
- Price: $1.03 to $1.67 a serving at list price, a gap of $232 a year at one serving a day.
- Other ingredients: check the label if you avoid gelatin or fillers.
How much magnesium you actually get
Only about 7.2% of magnesium L-threonate is magnesium. The 144 mg in a serving is about a third of the 420 mg a day men need and under half of the 320 mg women need, from food and supplements together (NIH). The “Magnesium” line on the Supplement Facts panel is the magnesium itself (the elemental amount), not the weight of the whole compound (NIH).
The human trials used 1 to 2 g of magnesium L-threonate a day, so the 2,000 mg label serving is the top of that range; do not double it. If you also take another magnesium, count both. The upper limit for adults is 350 mg a day of magnesium from supplements and medicines. Food does not count toward it (NIH). Taking L-threonate and glycinate together.
Is any magnesium L-threonate third-party tested?
One of the two. NSF/ANSI 173 lists Double Wood Magnesium L-Threonate (read 2026-11-02), which checks that the capsule holds what the label says. NSF records the label’s maximum, 8 capsules; the label serving is 4 capsules. We also searched NSF Certified for Sport, USP Verified, Informed Choice and Informed Sport on October 14, 2026 and found no listing for NOW Magtein. That does not mean its label is wrong; it means no outside program confirms it. If testing matters most to you, these magnesium glycinates are on a list.
Every size, ranked by cost
All 6 bottle sizes the brands sell
| Product | Size | List price | A serving |
|---|---|---|---|
| Double Wood Magnesium L-Threonate | Triple Pack (3 x 120 capsules) | $82.95 | $0.92 |
| Double Wood Magnesium L-Threonate | Double Pack (2 x 120 capsules) | $56.95 | $0.95 |
| Double Wood Magnesium L-Threonate | One Bottle (120 capsules) (linked) | $30.95 | $1.03 |
| NOW Magtein Magnesium L-Threonate | 100 Veg Capsules (In Stores Only) | $49.99 | $1.51 |
| NOW Magtein Magnesium L-Threonate | 180 Veg Capsules | $91.65 | $1.53 |
| NOW Magtein Magnesium L-Threonate | 90 Veg Capsules (linked) | $49.99 | $1.67 |
How these 2 magnesium L-threonate products were ranked
By cost a serving at each brand’s own list price: the price of the bottle our link opens, divided by its servings. Every serving is the same 144 mg, so this is also the cost per mg of magnesium. We quote no Amazon prices. Commission does not enter it; the rate is the same whichever you buy.
Questions
What is the best magnesium L-threonate supplement?
On cost, Double Wood Magnesium L-Threonate: 144 mg of magnesium (2,000 mg of Magtein) in 4 capsules, $1.03 a day at its list price. Both products we track use the same Magtein ingredient at the same dose, so the main difference is price. Double Wood is also on NSF/ANSI 173, a public testing list that checks the label; NOW is on none.
Which magnesium L-threonate is the cheapest?
Double Wood Magnesium L-Threonate at $1.03 a serving, then NOW Magtein Magnesium L-Threonate at $1.67, each at the brand’s one-bottle list price.
How many capsules give the 144 mg of magnesium on the label?
About 7.2% of the compound. A 2,000 mg serving of Magtein gives 144 mg of magnesium; that is the “Magnesium” line on each of these labels. It takes 4 capsules for Double Wood and 3 for NOW.
How much magnesium L-threonate should I take?
The trials used 1 to 2 g of magnesium L-threonate a day (about 72 to 144 mg of magnesium). The label serving, 2,000 mg, is the top of that range. Keep all magnesium from supplements at or under 350 mg a day (NIH).
Is magnesium L-threonate third-party tested?
One of the two we price is. NSF/ANSI 173 lists Double Wood Magnesium L-Threonate (NSF records the label’s maximum, 8 capsules; the label serving is 4 capsules). We searched five public testing lists; NOW Magtein was on none of them. NSF/ANSI 173 checks that the capsule holds what the label says.
Is magnesium L-threonate worth the price?
For most people, no. It costs $2.15 or more for 300 mg of magnesium, against $0.50 for our glycinate pick, and its human trials are small and company-funded. It makes sense only if memory is your goal. L-threonate vs glycinate: the evidence.
Related magnesium guides
- L-threonate vs glycinate: the evidence and our verdict · magnesium for sleep
- All magnesium forms compared · magnesium glycinate prices · magnesium citrate prices
- Best magnesium overall · how much magnesium per day · magnesium guide
Look up a magnesium L-threonate label
Want to check a product that is not on this page? Search our supplement label lookup for the label facts filed for it with NIH.
Sources
- Prices: each brand’s own list price (its regular one-time price) for every size it sells, checked October 14, 2026. We quote no Amazon prices; Amazon is only where the buy links go.
- Labels: Double Wood Magnesium L-Threonate (NIH label 315679, 144 mg per 4 capsules); NOW Magtein (NIH label 335276, 144 mg per 3 capsules).
- Testing lists: NSF/ANSI 173, NSF Certified for Sport, USP Verified, Informed Choice and Informed Sport, searched October 14, 2026.
- Trial doses: Liu 2016 (PubMed 26519439), Hausenblas 2024 (39252819), Lopresti 2026 (41601871).
- NIH Office of Dietary Supplements. Magnesium fact sheet for health professionals (RDA and the 350 mg upper limit).
This page is for information. It is not medical advice.