Antimony

Antimony sits in the same chemical family as arsenic and shows up in surprising places: brake dust, flame retardants in fabrics, plastic bottles left in the sun, mining regions, smelter emissions, and wildfire smoke. Most people carry only trace amounts, but exposure varies dramatically depending on where you live, what you do for work, and what you breathe. This test captures how much your body has been exposed to and eliminated over a full day.

A 24-hour urine collection is the standard approach for tracking metalloid exposure because it averages out the ups and downs of a single spot sample. Antimony (Sb) is an emerging exposure marker, not a diagnostic test for a specific disease, so the value of the number comes from understanding what has entered your body recently and how that compares with population reference points.

What This Test Actually Captures

Urinary antimony reflects recent exposure, typically within the past several days. Once antimony enters the body, the kidneys clear a large fraction into urine, so what shows up in a 24-hour collection is essentially a report of what you have absorbed and eliminated in that window. It does not measure long-term body burden or the amount stored in bone or tissue.

Background levels in general populations are strikingly low. In a Canadian national biomonitoring survey, the upper background value in the population aged 3 to 79 years was very small (well under one microgram per liter). In German children and adolescents, average levels were also very low, and only 79% of samples were even detectable. Earlier reviews suggested an upper background limit in the same low range in healthy unexposed adults. These are extremely small quantities.

Heart Attack, Heart Failure, and Cardiovascular Death

The strongest health signal in the literature comes from cardiovascular outcomes. In a prospective study of nearly 23,000 Danish never-smokers, people in the highest quartile of urinary antimony had about 52% higher risk of acute heart attack and 58% higher risk of heart failure compared with those in the lowest quartile.

A Spanish cohort study found a similar pattern: comparing the 80th to the 20th percentile of urinary antimony, cardiovascular incidence was about 51% higher. Antimony carried one of the highest inclusion probabilities in mixture models alongside cadmium, meaning it stood out even when other metalloids and metals were considered together.

The pattern extends to survival. In a U.S. NHANES analysis from 1999 to 2018, higher urinary antimony was linked to about 26% higher all-cause mortality and 44% higher cardiovascular mortality. An earlier NHANES analysis found that people in the highest quartile had roughly twice the odds of self-reported congestive heart failure compared with the lowest quartile.

Bone Density in Postmenopausal Women

In a Brazilian study of postmenopausal women, higher urinary antimony was linked to about twice the odds of osteoporosis after adjusting for age, body weight, menopause duration, smoking, and prolonged bed rest. Women with the highest urinary antimony had significantly lower bone density at multiple measured sites and a 44% osteoporosis rate compared with 18% in women with lower levels.

Sleep and Cognition

A NHANES analysis found that people in higher quartiles of urinary antimony had 66% to 93% higher odds of insufficient sleep (six hours or less per night) and about 57% higher odds of obstructive sleep apnea. For cognition, older adults showed a non-linear pattern: very low levels tracked with slightly better performance, but above a certain low threshold, the odds of cognitive impairment rose. Both findings come from cross-sectional data, so they show association, not cause.

Metabolic and Liver Signals

In U.S. adult data, higher urinary antimony was positively and linearly associated with hypertension and dyslipidemia (unhealthy cholesterol patterns), independent of body weight. In NHANES 2003-2018, higher urinary antimony was associated with about 18% higher odds of metabolic-associated fatty liver disease per unit increase in exposure, though antimony was not the dominant metalloid in mixture models.

Why One Reading Can Fool You

Urinary antimony is one of the least stable exposure biomarkers studied. In healthy adult men sampled on eight days over three months, the reproducibility (measured by an intraclass correlation coefficient, or ICC, where 1.0 would mean perfectly stable) was very poor. Values below 0.40 are considered poor. A Swedish biobank study of 24-hour urine samples found similarly low reproducibility for antimony, one of the lowest of any element tested.

This has practical consequences. Simulations suggest that when a biomarker has this level of variability, you might need many separate specimens to reliably estimate someone's long-term average exposure. Single-sample interpretation is unreliable, and even one 24-hour collection can misrepresent your usual level.

Common factors that can distort a single reading:

• Urine dilution: samples that are unusually dilute or concentrated can shift the number. Labs typically correct for this using creatinine or specific gravity, but very extreme values are often excluded entirely.
• Recent food, water, or air exposure: because antimony reflects recent intake, an unusual meal, a contaminated water source, or a smoky day can transiently move the number without indicating any lasting change.
• Detection limits: many labs have a very low detection floor for this metalloid. In one large study, 16% of samples were below the method detection limit and 65% were below the reliable quantification limit. Numbers reported near the floor carry substantial uncertainty.
• Iron or folic acid supplementation: in a pregnancy cohort, use of iron/folic acid supplements was one of the few identified predictors of higher urinary antimony, likely reflecting altered absorption or clearance rather than more actual exposure.

Tracking Your Trend

Because a single reading is so variable, the value of this test lies in tracking. If you have a known or suspected exposure source (a job, a home near a mining or smelter site, wildfire smoke exposure, a change in water source), a baseline followed by repeat testing over months tells you far more than one number in isolation. Two to three collections spaced weeks apart give a better picture of your usual level than any single sample.

For proactive tracking without a known exposure, an annual measurement is a reasonable rhythm to establish where you sit relative to population reference points. If a first result is meaningfully higher than typical background, a confirmation test within a few weeks helps distinguish a transient blip from a sustained elevation.

What to Do If Your Level Is Elevated

An unexpectedly high urinary antimony result is not a diagnosis. The first move is to think about exposure. Occupational settings with the clearest signals include mining, smelting, firefighting (wildfire response produced 45% to 56% increases in urinary antimony in non-smoking firefighters), plastic manufacturing, and battery or flame-retardant production. Environmental sources include drinking water from contaminated wells, proximity to industrial sites, and heavy household smoke or traffic exposure.

The reasonable next steps combine three tracks. First, retest after 4 to 6 weeks under normal conditions to confirm the pattern. Second, order a broader heavy metals panel (lead, mercury, arsenic, cadmium at minimum) since antimony rarely arrives alone and mixture exposures carry the strongest cardiovascular signals. Third, if the result is confirmed and elevated, an occupational or environmental medicine specialist can help identify the source and guide next steps. This is not the kind of result you should try to interpret in isolation.

Where This Test Sits in the Bigger Picture

Urinary antimony is an exploratory marker, not a settled clinical test. There are no universally agreed cutoffs that define "safe" versus "toxic" for individual health decisions, and the outcome data linking it to disease come mostly from observational studies. That said, the cardiovascular signal has now been replicated across multiple cohorts and metal-mixture analyses, which is why interest in antimony as a modifiable environmental exposure has grown. Getting a baseline now gives you your own data to compare against as the science matures.