short course
Energy & Fatigue
Vitamins & Minerals
An iron and active B vitamin formula from Thorne. Chelated iron bisglycinate pairs with vitamin C and active folate and B12 to support healthy red blood cell production. Thorne now sells it as Advanced Iron Complex.
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MARTYROSS10
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Quick Facts
Key Ingredients
Vitamin C 15 mg
Vitamin B6 5 mg
Third-party Testing
NSF Certified for Sport
Dietary
Dairy-free
Gluten-free
Soy-free
Written by
Dr. Marty Ross, MD
Updated
September 24, 2026
Dr. Ross's Expert Review
Fatigue has many causes, and low iron is a common one I see. Low iron can lead to low blood levels. Iron is also a key factor in energy reactions. Ferrasorb by Thorne is the iron formula I use most when labs suggest iron support is needed. It pairs iron bisglycinate with the nutrients that help iron do its job.
The iron here is chelated, which means it is bound to amino acids for absorption. In my clinical experience, this form is less likely to cause the constipation and stomach upset people can get from non-chelated iron forms. That matters, because the best supplement is the one a person actually keeps taking. Vitamin C is included because it supports iron uptake, and the B vitamins come in their active forms: folate as 5-MTHF, B12 as methylcobalamin, and B6 as pyridoxal 5′-phosphate. Those nutrients support healthy red blood cell production, and healthy red blood cells carry the oxygen that energy depends on.
I am candid about the limits of any iron supplement. A bottle does not replace finding out why iron is low in the first place. Absorption issues, blood loss, and diet all need a physician’s eye, and I want the cause worked up.
There are two cautions for this product. Keep it out of reach of children, because accidental iron overdose is a leading cause of poisoning in young kids. And anyone on methotrexate, especially for cancer therapy, clears folate supplements with their prescribing physician first.
Used for a defined stretch with follow-up labs, this is one of the cleanest iron formulas on my shelf.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Dr. Ross has a financial relationship with the Femologist store, where this product is sold.
How I Use It in My Practice
In my practice Ferrasorb is a short course supplement, not something people stay on indefinitely. I usually start at one capsule a day with food, and move up toward the label range of one capsule one to three times daily as tolerated. I rely on follow-up iron studies to tell us when the job is done. A patient’s physician should monitor the iron levels. Anyone on methotrexate should clear use of this product with their prescriber before starting. And I am firm on this: every iron bottle stays out of reach of children.
This reflects Dr. Ross's clinical experience and is educational, not medical advice. Work with your treating physician before starting, stopping, or changing any supplement or medication.
The Research, in Dr. Ross's Words
The truth is, nobody has studied this exact formula in a trial. The science here is based on the individual ingredients in this product.
The iron piece is the strongest. A 2023 review pooled 17 randomized trials of ferrous bisglycinate against iron salts. The findings show bisglycinate performed comparably against iron salts with fewer GI complaints. A 2022 randomized controlled trial in pregnant women with low iron found 24 mg of elemental iron as bisglycinate with folinic acid performed as well as 66 mg of ferrous fumarate, with better absorption and tolerability at a much lower dose. Dose matters here. This product gives 36 mg of elemental iron per capsule, which is on the high side, so I use one capsule once or twice a day rather than three.
The folate piece is real too. One controlled trial from 2000 compared L-5-MTHF head to head with folic acid. The B12 and vitamin C are cofactors; vitamin C is a well-accepted way to support iron uptake.
Keep iron away from thyroid medicine and from magnesium or calcium by at least two hours, because they block each other’s absorption. Accidental overdose of iron products is a leading cause of fatal poisoning in children under six, so keep the bottle out of their reach.
The human data on this specific combination is limited. In my practice I reach for it when someone needs iron and B vitamin support together, and I check ferritin and a CBC before and during use rather than guessing. For the best directions for your situation, discuss this product with your physician or healthcare provider.
References
From:
Thorne
Advanced Iron Complex provides iron in chelated form for optimal absorption and vitamin C to enhance iron’s absorption, plus the active forms of folate and vitamins B6 and B12 – offering comprehensive nutritional support for iron-deficiency anemia.
Directions of Use
Take 1 capsule one to three times daily or as recommended by your health-care practitioner.
Does not contain
dairy
gluten
soy
ALLERGY WARNING: This product is contraindicated in an individual with a history of hypersensitivity to any of its ingredients. PREGNANCY: If pregnant, consult your health-care practitioner before using this product. INTERACTIONS: 5-methyltetrahydrofolate (5-MTHF) supplementation is not recommended concurrent with methotrexate cancer therapy, as it can interfere with methotrexate's anti-neoplastic activity; however, this folate source has not been shown to interfere with the anti-inflammatory activity of methotrexate. An individual taking methotrexate for psoriasis or rheumatoid arthritis can safely take a supplement containing folate. ADDITIONAL WARNINGS: Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under six. Keep this product out of reach of children. In case of accidental overdose, call a doctor or poison control center immediately.
Excerpted from Thorne's product information. These statements have not been evaluated by the Food and Drug Administration.
Supplement Facts
Serving Size: 1 Capsule
Servings Per Container: 60
| One Capsule Contains | Amount | |
|---|---|---|
Vitamin C as Ascorbic Acid | 15 mg | |
Vitamin B6 as Pyridoxal 5'-Phosphate | 5 mg | |
Folate 400 mcg as L-5-Methyltetrahydrofolate†from L-5-Methyltetrahydrofolic Acid, Glucosamine Salt | 667 mcg DFE | |
Vitamin B12 as Methylcobalamin | 300 mcg | |
Iron as Ferrochel® Ferrous Bisglycinate Chelate††| 36 mg | |
†This product uses Gnosis S.p.A.'s L-5-Methyltetrahydrofolic Acid, Glucosamine Salt (Quatrefolic).
††This product uses Albion's Ferrochel Ferrous Bisglycinate chelate. | ||
Common Questions about Ferrasorb
Answers are general educational information, not medical advice for your situation.
Ferrasorb
By Thorne
From $25.00 · Save 10% with code MARTYROSS10
