Mercury, Blood
Other marker
Mercury (Blood)
Mercury, Blood
A toxic heavy metal measured in blood to assess recent exposure, most often to methylmercury from dietary fish and seafood. Chronic elevation is associated with neurological effects and, at higher levels, cardiovascular and renal toxicity.
PED Notes
The dominant source of an elevated blood mercury in a healthy adult is diet, specifically high intake of large predatory fish (tuna, swordfish, king mackerel, shark). That is directly relevant to physique athletes who eat very large amounts of fish for lean protein: someone eating multiple tins of tuna daily can accumulate a genuinely raised mercury over time. Some contaminated or unregulated supplements can also contribute. The fish angle is nuanced, because oily fish also supply the EPA/DHA that benefit cardiovascular and metabolic health, so the goal is smarter species selection rather than cutting fish out. Practical mitigation is to favour low-mercury sources (salmon, sardines, mackerel, shrimp) and rotate protein sources. Reference ranges are lab dependent; toxicity concern rises well above the general-population reference.
When high
When blood mercury is elevated:
- Review dietary fish intake, which is the usual driver. Athletes eating large daily volumes of tuna or other large predatory fish should reduce these and shift toward lower-mercury options (salmon, sardines, mackerel, herring, shrimp), which still deliver EPA/DHA.
- Review supplements for unregulated or contaminated products.
- Mercury is cleared slowly; levels fall over weeks to months once high-mercury intake stops. Re-test after a period of reduced exposure.
- Ensure adequate selenium status through diet, given its interaction with mercury metabolism, without resorting to megadoses.
- Markedly elevated levels or any neurological symptoms warrant medical and toxicology assessment; chelation is a specialist decision, not a self-directed one.
History Chart
Reading History
Frequently Asked Questions
Reference Ranges
Standard Range
VitalMetrics Range