Iron

Iron is functional, but sensitive.

It plays a central role in oxygen transport and cellular energy processes,
primarily through its involvement in hemoglobin.

At a high level, evaluation comes down to three signals:

• Form (ferrous vs ferric, bisglycinate, etc.) — differences in absorption and tolerability
• Dose relative to need — alignment with deficiency status rather than baseline intake
• Absorption context — interaction with enhancers such as vitamin C and inhibitors such as calcium

Iron is one of the few nutrients where excess carries meaningful risk.

It is not universally beneficial.
Its relevance depends on deficiency, not assumption.

More is not neutral.
Context determines safety.