Thorne vs Doctor's Best Magnesium Glycinate (2026)
Informational comparison of label data and cost — not medical advice. Prices are live per-serving figures; formulas are each brand's published Supplement Facts.
Thorne Magnesium Bisglycinate and Doctor's Best High Absorption Magnesium are, chemically, the same product: 200mg of elemental magnesium as a chelated glycinate compound. The only real difference is that Thorne is NSF Certified for Sport and costs nearly double — $0.87/day vs $0.46/day. Unless you're drug-tested, Doctor's Best gives you the identical form and dose for less.
The numbers, side by side
| Thorne Magnesium Bisglycinate | Doctor's Best High Absorption Magnesium | |
|---|---|---|
| Form | Chelated bisglycinate | Chelated bisglycinate |
| Elemental Mg / serving | 200mg | 200mg |
| Serving size | 1 capsule | 2 tablets |
| Servings/container | 60 | 60 |
| Third-party cert | NSF Certified for Sport | None |
| Price | $26.00 | $13.99 |
| Cost/day | $0.87 | $0.46 |
Prices are live Amazon buy-box figures (Creators API, July 2026) ÷ pack serving count. Formula details are each brand's published Supplement Facts panel.
The real difference: certification, not chemistry
Both products use the same chelated glycinate (bisglycinate) form, which comparative bioavailability research finds among the best-absorbed of common magnesium compounds (Firoz & Graber 2001, PMID 11794633), and both land at 200mg of elemental magnesium per serving — identical active ingredient, identical dose. Glycinate's chelation is also what makes it the gentlest form on the stomach, versus the osmotic laxative effect of citrate or the poor absorption of oxide.
The one thing that actually separates them is NSF Certified for Sport, which Thorne carries and Doctor's Best does not. That certification screens for 280+ banned substances on top of confirming label accuracy — the standard drug-tested athletes and professional leagues require. It's a real, meaningful difference if you're in that group. If you're not, you're paying nearly double for a certification you don't need on a product that is otherwise the same compound at the same dose.
Who each one is for
Choose Doctor's Best if you want the same chelated glycinate form at 200mg elemental magnesium for less money, and you don't need drug-tested-athlete certification.
Choose Thorne if you're a drug-tested athlete or competitor and need NSF Certified for Sport verification — worth the premium specifically for that reason.
Choose neither if you want a form-agnostic, cheapest-per-dose option — our full magnesium rankings include a budget powder at $0.18/day.
Our picks
200mg elemental magnesium, chelated glycinate. $0.46/day, no certification.
Same 200mg chelated glycinate form, NSF Certified for Sport. $0.87/day.
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Frequently asked questions
Is Thorne or Doctor's Best magnesium glycinate better?
Same active ingredient — 200mg elemental magnesium as chelated bisglycinate. The only real difference is Thorne's NSF Certified for Sport testing. Unless you need that certification, Doctor's Best delivers the identical form and dose at roughly half the daily cost.
Why is Thorne magnesium more expensive than Doctor's Best?
Mostly the NSF Certified for Sport testing (280+ banned substances screened). $0.87/day vs $0.46/day for the same 200mg chelated glycinate dose — you're paying for the certification, not a different compound.
Is Doctor's Best magnesium glycinate third-party tested?
No. It carries no USP or NSF certification. That doesn't mean the label is wrong, just that no independent lab has confirmed it. Thorne (NSF Sport) and Nature Made (USP Verified) are the certified alternatives.
Which magnesium glycinate is best for athletes?
Thorne Magnesium Bisglycinate — NSF Certified for Sport, the certification most drug-tested competitions require. Doctor's Best is the same form and dose without that verification.
Related
- Best magnesium supplements — all forms ranked by cost per effective dose
- Glycinate vs citrate — which form for which goal
- All magnesium glycinate products
Sources
- Firoz M, Graber M. "Bioavailability of US commercial magnesium preparations." Magnes Res. 2001;14(4):257-62. PMID: 11794633
- Product labels: Thorne Magnesium Bisglycinate, Doctor's Best High Absorption Magnesium, manufacturer Supplement Facts panels, plus live Amazon pricing, July 2026.