250–500 mg/day of purified extract.
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Shilajit is a dark brown to black resinous substance that oozes from cracks in the rocks of the Himalayan, Altai, and Caucasus ranges and other high mountains of Central Asia; it forms over centuries through the slow decomposition of plant matter compressed under geological pressure, a process that produces a complex mixture rich in fulvic and humic acids, trace minerals, dibenzo-alpha-pyrones (DBPs), and other bioactive compounds; Ayurvedic medicine considers it one of the most potent rasayanas (tonics for longevity and vitality) in the traditional repertoire, with documented use for more than 3,000 years for fatigue, infertility, male sexual weakness, anemia, urinary problems, and as a general "rejuvenation" tonic.
The active principles identified with the greatest clinical relevance are fulvic acids (chelating compounds able to carry minerals across cell membranes) and dibenzo-alpha-pyrones (DBPs), a family unique to shilajit with antioxidant, mitochondrial, and mineral-modulating activity documented in preclinical studies; pharmaceutical-grade purified products (processed to remove contaminants and concentrate the active principles) are significantly superior in clinical and safety profile to unpurified products, which have been a subject of regulatory concern because of heavy metal contamination.
The strongest indication from a modern clinical perspective is the improvement of fatigue and physical performance: several small trials have documented significant improvements in fatigue scales, exercise capacity, and markers of muscle mitochondrial function with supplementation at 250-500 milligrams per day of purified shilajit for 8-12 weeks, an indication consistent with traditional use and with the role of fulvic acids in mitochondrial function.
In male infertility with oligospermia or asthenospermia, a randomized Indian trial published in 2010 with 60 infertile men showed significant improvements in sperm concentration, motility, and morphology with 200 mg twice a day of purified shilajit for 90 days, along with modest increases in total testosterone; these effects are consistent with traditional use as a male reproductive tonic.
An additional study from the same group published in 2016 documented significant increases in total and free testosterone, along with improvements in physical performance markers, with supplementation at 500 mg/day for 12 weeks in healthy adult men.
In cognition, several preclinical studies have documented neuroprotective effects and cognitive improvements with shilajit, attributed to fulvic acids and their ability to modulate the pathological protein aggregation characteristic of Alzheimer's disease and other neurodegenerations; human clinical data are still preliminary but consistent with the preclinical line.
Shilajit provides bioavailable trace minerals (iron, magnesium, zinc, manganese, copper, selenium, and others) in forms chelated by fulvic acids, which improves their intestinal absorption; this feature is consistent with its traditional use in mild anemias and subclinical mineral deficiencies.
The doses studied range from 200 to 500 milligrams daily of pharmaceutical-grade purified shilajit, divided into one or two doses with or without food; quality products state the geographic origin, the purification process, and the fulvic acid content (ideally at least 15-50 percent); the most common commercial forms are pure resin (the most concentrated and traditional, with a characteristic bitter-mineral taste), capsules with dry extract, and dissolvable powders; the effect on fatigue and vitality appears gradually and requires at least 4-8 weeks for clinical evaluation.
The most important safety consideration is product quality: unpurified shilajit or shilajit of uncertain origin may be contaminated with heavy metals (lead, arsenic, mercury), mycotoxins, or free radicals, which paradoxically turns the "purifying" supplement into a source of significant toxicity; people who use shilajit should choose products with purity certification and specific heavy-metal testing; the adverse effects described with purified products are rare and mild (mild digestive discomfort, a persistent unpleasant taste); people with hemochromatosis, thalassemia, or other iron overload conditions should avoid shilajit because of its significant iron content; those who take drugs whose absorption could be altered by chelation should space out their doses; in pregnancy and breastfeeding the data are limited and it is discouraged as a precaution; people with hormone-sensitive cancers (prostate) should use caution because of its effect on testosterone; in people with serious kidney disease, prior evaluation is advisable because of the concentrated mineral content.
Information, not medical advice. Scientific evidence reflects the quality of the studies.