Which form should you actually buy?
Side-by-side comparisons of supplement forms, doses and timing. Every number is traced to its original study, and where the evidence runs out, we say so.
Start with a comparison
The question most people are actually asking at the shelf.
Folate vs Folic Acid
Folic acid is the only folate form with neural tube defect trial evidence behind it. The 2020 label rule changed the unit, and half of US labels hide the math.
Magnesium Glycinate vs Magnesium Citrate
Citrate has real human absorption data. Glycinate has almost none. No trial has compared the two head-to-head, and citrate's elemental content depends on the salt.
Magnesium Glycinate vs Magnesium Oxide
Magnesium oxide carries 4x more elemental magnesium per mg, but the only head-to-head trial found no absorption difference. What labels don't tell you.
Probiotics vs Prebiotics
Probiotics are live microbes, prebiotics their fuel. But half of US probiotic labels name no strain, and no product we checked reached a prebiotic dose.
More comparisons in progress
vitamin D2 vs D3, ubiquinol vs ubiquinone.
Browse by ingredient
Every form an ingredient is sold in, what the label numbers mean, and the dosing limits.
What makes this different
Numbers that survive checking
The absorption figures repeated across supplement sites mostly trace back to studies that measured something else, or to nothing at all. We check before we publish.
Evidence has a grade
Every claim is marked Strong, Limited or None. A supplement with no controlled trials is labelled that way instead of being described in confident language.
Label maths you can use
A 500 mg capsule is 500 mg of a compound, not of the mineral. We show the conversion so you can compare two bottles honestly.
MilligramLab is an information resource, not a medical service. Nothing here is a diagnosis, a treatment plan, or a recommendation to take any product. Speak to a doctor or pharmacist before starting a supplement.