Thorne Iron Bisglycinate vs Nutrition Geeks Iron

Pros

• ✓Bisglycinate (Ferrochel®) form is highly bioavailable and consistently reported as gentle on the stomach with no constipation or nausea
• ✓Measurable improvements in ferritin and hemoglobin confirmed by multiple reviewers via blood tests
• ✓NSF Certified for Sport — independently verified for purity and label accuracy
• ✓Ultra-clean formula: only pharmaceutical-grade excipients, no magnesium stearate, fully vegan and allergen-free

Cons

• ✗No vitamin C included — absorption is suboptimal without pairing with ascorbic acid (users note this and add their own)
• ✗25 mg dose may be insufficient for severe iron deficiency recovery; therapeutic correction often requires higher daily intake
• ✗Premium pricing — noticeably more expensive per serving than ferrous sulfate or gluconate alternatives
• ✗At least one reviewer with chronic severe malabsorption found no improvement, ultimately requiring IV iron infusion

Best For

Pros

• ✓Multiple reviewers report noticeable reduction in fatigue and tiredness within days
• ✓Very small tablets — easy to swallow, widely noted by reviewers
• ✓365-tablet supply offers excellent value at roughly 12 months per pouch
• ✓Ferrous fumarate is a well-absorbed iron form with solid clinical backing

Cons

• ✗At least two orders reportedly contained fewer than 365 tablets — quality control concern
• ✗One reviewer noted stomach discomfort, a known risk with ferrous fumarate at higher doses
• ✗Not third-party tested, so label claims cannot be independently verified
• ✗No vitamin C included in the formula to aid iron absorption

Best For