1. MAS Iron
MAS earns the top spot because it uses the most scientifically-proven, bio-available form of iron combined with cutting-edge ingredients that no other supplement contains. Each ingredient has demonstrated the ability in published research to enhance absorption by 30% to 40%.
This is the iron supplement truly built for the needs of runners.
Not only does it use a higher dose to compensate for the unique ways runners lose iron that the general population doesn’t, but in our testing it was the easiest on the stomach, even when taken before hard workouts.
It’s formulated with ferrous bisglycinate, an iron atom chelated (bound) to two molecules of glycine, which protects it through the stomach. Research has shown that this form of iron is 4x more bioavailable compared to other forms of iron and resulting in 50% less stomach issues.
It also contains 3 other ingredients that help boost how much you’re able to absorb.
Alpha-GPC acts as a shield that helps carry more iron through the intestinal wall, which produces up to 4x the absorption vs. iron alone.
Vitamin C helps convert ferric (Fe3+) to ferrous (Fe2+) and shields it from calcium interference. Research has shown that adding vitamin C to an iron-rich meal produces a 2.9x increase in absorption.
BioPerine is a standardized black pepper extract clinically shown to increase iron bioavailability by 40%.
Each enhancer addresses a different bottleneck to iron absorption.
Most iron supplements would stop there, but increasing iron stores does little if your body can’t use it.
Studies have shown that 30% of iron-deficient runners are also B-vitamin deficient. This is important because Vitamin B6 and Vitamin B12 are required to convert iron into functional hemoglobin and red blood cells, which is what moves the needle for running performance.
MAS Iron isn’t the cheapest of those we tested. Thorne and MegaFood were both cheaper, but when you factor in dosage and absorption ingredients, MAS offers a unique value.
What it does well
- Uses a proven dosage from a 2014 trial shown to be most effective at raising iron levels in runners.
- Unique ingredients such as Alpha-GPC, vitamin C and BioPerine that no competitor includes.
- B6 and B12 for building the iron into red blood cells
- 50% less Gi and stomach issues compared to traditional iron supplements
- 30-day money back guarantee
Where it falls short
- The most expensive option here at $34.95 a bottle
- Wrong product for anyone with hemochromatosis or iron overload
- Give it 60 to 90 days before you retest
