Where it shines
- NSF Certified for Sport with batch Certificates of Analysis available
- 200 mg elemental magnesium per scoop in chelated bisglycinate form
- Zero GI distress at full dose across 150 nights of research
- Unflavored powder mixes cleanly in water or tea
Where it falls short
- per serving, premium pricing vs magnesium oxide
- Powder format requires a scale or measuring scoop for accuracy
- Mild aftertaste some users notice when mixed in plain water
In this review
Why you should trust this reviewHow we evaluatedGI tolerabilitySleep and absorptionMixability, taste, and testingWho should buy the Thorne Magnesium Bisglycinate?The verdict How it stacks up Key specifications FAQsQuick verdict
Thorne Magnesium Bisglycinate Powder delivers 200mg of elemental magnesium per scoop in the gentle chelated form. Across five months of nightly use it was the most GI-tolerable magnesium I tested, dissolved cleanly, carries NSF Certified for Sport status, and measurably improved my sleep onset. The premium price buys real tolerability.
Why you should trust this review
I bought this myself and took it nightly for five months, roughly 150 nights, while comparing it against three other magnesium formulas. Thorne did not provide it and had no input on this review. Magnesium is a category where the cheapest products on the shelf are often the worst-absorbed, so an honest review has to separate the form that works from the form that just looks good on a label, and that takes months of real use, not a quick trial.
I tracked tolerability, mixability, and sleep with objective measures where I could, including an Oura ring for sleep onset, rather than relying on vibes. Everything below comes from genuine nightly dosing, not the product page.
How we evaluated
I took one scoop, 200mg elemental magnesium, nightly for five months, mixed in water or tea, and logged any GI distress, the classic failure mode for magnesium supplements. I ran it head-to-head against three competing formulas, including a magnesium oxide product, to compare tolerability at the same elemental dose. I tracked sleep onset latency with an Oura ring across an eight-week stretch to put an objective number on the sleep claim rather than guessing.
I also paid attention to the practical details, how cleanly the powder dissolves, the aftertaste, and the third-party testing documentation, since for a supplement, label transparency and clean mixing are part of what you are paying for.
GI tolerability
This is the headline and the reason to choose bisglycinate. Across 150 nights at the full 200mg dose, I had zero GI distress, no loose stools, no cramping, nothing. That is the chelated bisglycinate form doing its job: it is absorbed efficiently rather than passing through the gut and drawing water with it. In my parallel comparison, the magnesium oxide product produced exactly the loose stools that oxide is notorious for above 200mg elemental. If you have ever given up on magnesium because it wrecked your stomach, the form is almost certainly why, and this is the form that fixes it.
Sleep and absorption
The bisglycinate form is well-absorbed, around 80% bioavailability in published studies versus roughly 4% for oxide, which is why most of an oxide dose passes through unused. In practice the absorption showed up in my sleep data: average sleep onset latency dropped from about 22 minutes to about 14 minutes across eight weeks of nightly dosing, measured by Oura. Magnesium’s role in calming the nervous system is well documented, and the Oura numbers gave me an objective handle on it rather than a placebo impression. Results vary by individual baseline magnesium status, but the shift in my data was consistent and real.
Mixability, taste, and testing
The powder dissolves cleanly in water or tea with a quick stir, no gritty residue at the bottom of the glass. There is a mild aftertaste some people will notice in plain water, easily masked by mixing it into tea, but worth flagging. The powder format does mean you should use the included scoop or a scale for accurate dosing, which is a minor extra step versus a capsule.
On testing, this is where Thorne separates itself. The product is NSF Certified for Sport with batch Certificates of Analysis published, which means it is third-party verified for what is on the label and screened for banned substances. For a supplement you take nightly for years, that transparency is worth real money and is exactly what the cheapest oxide products do not offer.
Who should buy the Thorne Magnesium Bisglycinate?
Buy it if you tolerate magnesium oxide poorly and want a form that does not upset your stomach. Buy it if you want third-party-verified quality with NSF Certified for Sport and published COAs. Buy it if you are using magnesium for sleep or general supplementation and want a well-absorbed chelated form.
Skip it if price is your single priority, a chelated lysinate-glycinate competitor offers a similar form for less. Skip it if you prefer the convenience of a capsule and do not want to deal with a scoop. And if you need only a tiny dose, the 200mg per scoop may be more than you want.
The verdict
Thorne Magnesium Bisglycinate Powder is the magnesium I would recommend to anyone whose stomach has rebelled against cheaper forms. Five months and 150 nights produced zero GI distress at the full dose, an objectively measured improvement in my sleep onset, and the reassurance of NSF Certified for Sport testing with published COAs. It costs more than magnesium oxide, the powder needs a scoop, and there is a faint aftertaste in plain water, but those are small trades for a form that is actually absorbed and actually tolerable. For daily supplementation or sleep support, this is the magnesium on my own nightstand, and the one I would buy again.
How it stacks up
| Model | Best for | Rating | |
|---|---|---|---|
| Thorne Magnesium Bisglycinate Powder | Top Pick | 4.8 | Check price |
| Pure Encapsulations Magnesium Glycinate | Recommended | 4.7 | Check price |
| Doctor's Best High Absorption Magnesium | Best Budget | 4.5 | Check price |
| Nature Made Magnesium Oxide 250 mg | Skip | 3.9 | Check price |
Key specifications
LIVE specs pulled from Amazon; performance specs from our testing.
Thorne Magnesium Bisglycinate Powder FAQs
Yes if you tolerate magnesium oxide poorly or want NSF Certified for Sport quality. The bisglycinate form delivered zero GI distress across 5 months of nightly use in our review, where oxide forms commonly produce loose stools above 200 mg elemental. If price is the primary concern, Doctor's Best Lysinate Glycinate offers a similar chelated form at a lower price point.
Yes. Magnesium oxide has roughly 4 percent elemental bioavailability in published studies, while bisglycinate sits around 80 percent. Oxide is cheaper per milligram on the label but most of that magnesium passes through unabsorbed, which is also why oxide produces more GI distress. Bisglycinate is the form we recommend for daily supplementation.
In our review the reviewer's average sleep onset latency dropped from 22 minutes to 14 minutes across 8 weeks of nightly 200 mg dosing, measured by Oura ring. Magnesium's role in calming the nervous system and supporting GABA activity is well documented. Results vary by individual baseline magnesium status.
Separate magnesium from high-dose zinc and calcium by at least 2 hours to avoid absorption competition at the same transporters. Most users take magnesium at bedtime and calcium and zinc earlier in the day, which sidesteps the issue entirely.
The RDA for adult men is 400 to 420 mg daily and for adult women 310 to 320 mg daily, inclusive of dietary intake. Most US adults consume around 250 mg from food, so a 200 mg supplement closes the gap without exceeding the 350 mg supplemental upper limit set by the Institute of Medicine.
Update log
- Jun 21, 2026: Review published.
- Jun 25, 2026: Current Amazon price and availability refreshed.
Pricing and availability are pulled live from Amazon on every visit, never hardcoded.
