Bioavailability is how much of what you swallow actually reaches your body. It is often oversold with precise-sounding numbers that do not hold up.

This tool skips the invented multipliers and gives what the evidence supports for each nutrient: what helps absorption, what gets in the way, and where a popular claim is weaker than it sounds. Pick a nutrient to begin.

Why there is no multiplier here

Real absorption depends on the nutrient, the form, the meal, and the person. A single times-better figure often comes from one small study.

So the tool gives direction instead: what tends to help, what tends to hinder, and where a common claim is shakier than the marketing suggests.

Making the gains count

Use the guidance to get more from what you already take, mostly by pairing nutrients with the right foods and spacing them from things that block them.

The gains are real but usually modest. The NIH notes that in a typical Western diet, enhancers and inhibitors of iron absorption have little effect on most people's iron status. They matter most for nutrients that absorb poorly to begin with, such as non-heme iron and curcumin.

When boosting is not the goal

Absorbing more is not always wanted. People with an iron overload condition, such as hemochromatosis, should not try to raise iron absorption, and vitamin C is often avoided in that case too.

For any nutrient with an upper limit, absorbing more is not automatically better. The Upper Limit Checker adds a nutrient up across your products against the published limit.

Put it together

Absorption starts with the right amount, so the Elemental Mineral Calculator shows the real mineral behind a compound weight. The Supplement Stack Builder lists what people commonly discuss for a goal, and the Cost Per Dose Calculator shows what each dose costs.

Absorption varies by person, form, and meal, and some popular claims come from single, small, or industry-funded studies, so treat all of this as general direction, not personal advice.

Where this comes from

Absorption relationships for iron are described in the NIH Office of Dietary Supplements iron fact sheet.

The same office explains vitamin C's role in the vitamin C fact sheet.

This calculator is for general education only and is not medical or professional advice. Always check product labels and speak with a qualified professional before making decisions about supplements.