A standard multivitamin is built for an average person who does not exist. The doses are set near the RDA floor, the forms are chosen for shelf life rather than absorption, and everything is pressed into one tablet whether the ingredients cooperate or not.
Three quiet failure modes
- Cheap forms. Magnesium oxide and cyanocobalamin are common because they are inexpensive and stable, not because they absorb well. Citrate, glycinate and methylcobalamin cost more and do more.
- Nutrient interference. Calcium competes with iron for absorption, and zinc taken with iron blunts both. A single tablet guarantees these collisions happen at the same moment.
- Wrong targets. If your vitamin D is fine but your B12 is low, a uniform blend overshoots one and undershoots the other. You pay for milligrams your body discards.
What actually moves the needle
Start from your own signals: sun exposure, diet pattern, sleep, training load, symptoms like cramps or brain fog. Those predict the most common gaps surprisingly well, and a blood panel confirms them. A formula mixed from that picture gives you meaningful doses of the three to five nutrients you are actually short on - and skips the rest.
That is the entire idea behind the Mythamin quiz: map your likely gaps first, supplement second.
