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Thorne vs NOW Foods Iron Bisglycinate (2026)
Disclosure: We earn commissions on purchases made through our links. This never influences our scores. Editorial policy
The Verdict
Thorne scores higher on our rubric (94 vs 88 on our 0-100 execution score), largely on its NSF Certified for Sport testing and hypoallergenic formulation. NOW Foods is the value pick at about $0.10 per dose versus Thorne's $0.27, and carries the Best Value badge in our iron scoring. In our view, if you want the highest-tested option, Thorne earns its score; if you want the same gentle bisglycinate form at the lowest cost, NOW Foods is an excellent value. Both avoid the constipation of ferrous sulfate.
Thorne Iron Bisglycinate
Thorne
NOW Foods Iron Bisglycinate 36mg
NOW Foods
Head-to-Head Comparison
| Category | Thorne Iron Bisglycinate Thorne | NOW Foods Iron Bisglycinate 36mg NOW Foods |
|---|---|---|
| Brand Score | 94/100Winner | 88/100 |
| Dosing & Form | 25/25Winner | 25/25 |
| Purity | 25/25Winner | 20/25 |
| Value | 21/25 | 23/25Winner |
| Transparency | 23/25Winner | 20/25 |
| Cost/Day | $0.27 | $0.10Winner |
| Dose/Serving | 25mg | 36mg |
| Form | ferrous bisglycinate chelate capsule | iron bisglycinate chelate vegetable capsule |
| Third-Party Tested | ✓ Yes | ✓ Yes |
| Proprietary Blend | No | No |
Why This Comparison Matters
Thorne and NOW Foods both use iron bisglycinate - the gentle, well-absorbed chelated form that causes less constipation and GI upset than ferrous sulfate. Thorne is the practitioner-grade option with NSF Certified for Sport; NOW Foods is the value pick with NPA GMP-audited manufacturing. This is the practitioner-versus-value iron decision for people who want the gentle form.
Bisglycinate is the form worth seeking if standard iron pills upset your stomach. Both products deliver it; the split is certification and cost.
We scored both on evidence, quality, cost per dose, and transparency.
Detailed Score Breakdown
Thorne Iron Bisglycinate
Thorne
25mg elemental iron as ferrous bisglycinate chelate - a well-studied chelated form with strong clinical evidence for efficacy and tolerability
NSF Certified for Sport - verified free of 270+ banned substances and tested for label accuracy. Thorne manufacturing exceeds FDA cGMP standards. The gold-standard certification in the supplement industry.
$0.27/day at 25mg (one capsule). At a therapeutic 50mg dose, about $0.53/day. Premium pricing is justified by NSF Certified for Sport status.
Fully disclosed label. Iron form specified as bisglycinate chelate. No proprietary blends. Minimal excipients. NSF certification seal displayed.
NSF Certified for Sport makes this the top choice for competitive athletes and anyone prioritizing certification rigor. Clean capsule with minimal excipients.
NOW Foods Iron Bisglycinate 36mg
NOW Foods
36mg elemental iron as bisglycinate chelate - above the RDA for premenopausal women (18mg) and appropriate for mild-to-moderate deficiency repletion
NPA GMP audited facility. NOW Foods performs third-party testing and publishes certificates of analysis. No USP or NSF certification on this specific product.
$0.10/day at 36mg - the best price-per-mg of elemental iron among the bisglycinate products here. Strong value.
Good disclosure. Iron form specified as bisglycinate chelate. Serving size and elemental iron amount clearly stated. Some non-essential excipients present (silica, stearic acid) but all individually disclosed.
The most cost-effective bisglycinate option in this comparison. Good choice for budget-conscious buyers who do not require NSF or USP certification.
How We Compared These Products
Every product in our database is scored on four equally-weighted pillars: dosing accuracy and form quality, purity verification (third-party testing), cost per clinically effective dose (not cost per pill), and label transparency. Each pillar is worth 25 points for a total of 100.
Cost per effective dose is calculated using the clinically studied dose from published research, not the manufacturer's suggested serving. If a product requires multiple servings to reach the dose used in clinical trials, that cost is reflected in the value score.
For a full explanation of our scoring methodology, see our methodology page. Prices were last checked on the dates listed for each product and may have changed.
More Iron (Bisglycinate) Comparisons
We earn commissions on purchases made through our links. This never influences our scores or recommendations. See our editorial policy.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare professional before starting any supplement regimen.