Your body eliminates mercury on its own, but the process is slow. The half-life of methylmercury (the most common form from dietary exposure) is roughly 45 to 80 days in the body, meaning it takes months to clear even after exposure stops. Speeding up that process safely depends on the type and severity of your exposure, and some popular “detox” methods carry real risks.
How Mercury Leaves Your Body Naturally
Mercury elimination happens in phases. In blood, methylmercury clears with a half-life of about 32 to 60 days. In the brain, clearance is slower, with estimates ranging from 38 to 79 days based on primate studies. “Half-life” means it takes that long for your levels to drop by half, so reaching negligible levels after significant exposure can take six months to a year or more, assuming no new mercury is entering your system.
This natural timeline is the baseline. Everything else you do, from dietary changes to medical treatment, either removes ongoing sources of exposure or attempts to speed up what your body is already doing.
Stop the Exposure First
No detox strategy works if mercury keeps entering your body. The two most common sources for most people are diet (especially fish) and dental amalgam fillings.
Fish and Seafood
The EPA and FDA recommend eating 2 to 3 servings per week from fish lowest in mercury, or 1 serving per week from moderately contaminated species. If you’re actively trying to lower your mercury levels, stick to the lowest-mercury options: salmon, sardines, shrimp, tilapia, pollock, catfish, anchovies, trout, and scallops. Pregnant or breastfeeding women should stay within 8 to 12 ounces per week of these low-mercury choices.
The fish to avoid entirely during a mercury reduction period are the high-mercury species: swordfish, shark, king mackerel, tilefish, bigeye tuna, and marlin. If you eat locally caught fish, check your state’s fish advisories. When no advisory exists, limit yourself to one serving that week and skip other fish.
Dental Amalgam Fillings
Silver-colored dental fillings contain about 50% mercury and can release small amounts of mercury vapor, particularly when you chew, grind your teeth, or drink hot liquids. If you choose to have amalgam fillings removed, the removal process itself can cause a significant spike in mercury exposure if not done carefully.
The Safe Mercury Amalgam Removal Technique (SMART), developed by the International Academy of Oral Medicine and Toxicology, involves specific protective measures: a non-latex rubber dam sealed in the mouth, external oxygen delivered through a nasal mask so you don’t inhale vapor, high-volume air filtration to capture airborne mercury, copious water irrigation to reduce heat, and sectioning the filling into large chunks rather than drilling it into fine dust. The patient swallows a slurry of charcoal or chlorella beforehand to bind any mercury that reaches the digestive tract. Both the dental team and the patient wear full protective barriers. Not every dentist follows this protocol, so if amalgam removal is part of your plan, look for a practitioner specifically trained in SMART procedures.
Medical Chelation Therapy
For people with confirmed mercury poisoning, chelation therapy is the primary medical treatment. Chelation uses pharmaceutical agents that bind to mercury in the body and carry it out through urine or stool. The two agents used most often are DMSA (taken orally) and DMPS (available orally or transdermally, typically dosed around 3 mg per kilogram of body weight).
Chelation is not a casual intervention. It comes with serious risks that make unsupervised use dangerous. Chelating agents don’t only grab mercury. They also strip essential minerals like zinc from your tissues, potentially causing deficiencies that impair organ function. Prolonged treatment can cause liver and kidney stress through oxidative damage and mineral redistribution. One of the more concerning effects is that chelators can actually move metals between organs rather than simply removing them, sometimes concentrating toxic metals in the liver or kidneys. This redistribution can trigger new damage in tissues that weren’t previously affected.
Because of these risks, chelation should only happen under medical supervision, with regular monitoring of mineral levels and kidney and liver function. Blood and urine mercury levels guide the decision to start treatment, though interpreting those results is tricky. Levels below 10 to 20 micrograms per liter fall near normal population ranges, where correlation with symptoms becomes unreliable. Mercury concentrations in blood and urine show surprisingly little correlation with the symptoms of mercury poisoning, which means a “detox” provider who bases treatment solely on a urine challenge test may be overstating the problem.
Selenium’s Protective Role
Selenium has an extremely high binding affinity for mercury. When selenium encounters mercury in the body, it forms an insoluble compound that effectively locks the mercury away, reducing its ability to cause damage. This is genuinely protective, but there’s a tradeoff: mercury that binds to selenium diverts selenium away from its normal job of supporting critical antioxidant enzymes. In this way, mercury toxicity is partly a selenium deficiency problem, because mercury hijacks the selenium your body needs for other functions.
Eating selenium-rich foods supports your body’s natural defense against mercury. Brazil nuts are the most concentrated dietary source (just one or two nuts per day provides more than enough). Other good sources include tuna, sardines, eggs, sunflower seeds, and mushrooms. Supplementing with selenium is possible but requires caution, since selenium itself becomes toxic at high doses. Staying within 200 micrograms per day from all sources is a reasonable upper boundary for most adults.
Supplements and Herbal Binders
Chlorella and cilantro are the two supplements most commonly recommended in natural health circles for mercury detox. The evidence for both is limited and mostly comes from animal studies.
Chlorella, a type of algae, appears to increase mercury clearance from the digestive tract, muscles, and connective tissue. It likely works by binding mercury in the gut and preventing reabsorption, which is why it’s used as a pre-procedure rinse during amalgam removal. As a daily supplement, it may modestly accelerate elimination of mercury that cycles through the digestive system, but no large human trials have confirmed specific dosing or measurable outcomes.
Cilantro (coriander leaf) has weaker evidence. Two published studies suggested it could improve mercury clearance in poisoned patients, but cilantro forms a weaker bond with heavy metals compared to compounds found in garlic and milk thistle. Animal studies on cilantro’s effects showed results mainly in bone tissue rather than soft tissues, and researchers noted that the dose-response relationship wasn’t consistent enough to consider the findings reliable. Some practitioners worry that cilantro could mobilize mercury from tissues without binding it tightly enough to escort it out, potentially redistributing it, though this concern is based more on theory than documented human harm.
Garlic and milk thistle showed stronger metal-binding properties in the same comparative research. Garlic’s active compound binds heavy metals more effectively than cilantro, and milk thistle’s key compound also outperformed it. Both are widely available and generally well tolerated, making them reasonable additions to a broader strategy even though the human evidence remains preliminary.
A Practical Approach
For most people with low-level mercury concerns from fish consumption or amalgam fillings, the most effective strategy combines source reduction with patience. Switch to low-mercury seafood, eat selenium-rich foods regularly, and give your body the months it needs to clear what’s already there. Adding chlorella or garlic as supplements is low-risk and may help at the margins.
If you suspect significant exposure from occupational contact, a broken thermometer, or contaminated products, get a blood or urine mercury test through your doctor. Levels well above 20 micrograms per liter warrant a conversation about chelation therapy. Levels near or below that range are harder to interpret and don’t necessarily mean you need aggressive treatment. Be wary of any practitioner who recommends chelation based solely on a “provoked” urine test (where a chelating agent is given before the test to artificially inflate the numbers), as this method overstates actual body burden and has led to unnecessary treatment.