Fulvic acid is not a single compound. It is the part of humic substances that stays dissolved in water at any pH, so the figure a lab reports depends on the method used to separate it. Published figures for shilajit and its extracts range from about a fifth to about three quarters fulvic acid. If you are thinking of taking shilajit for a health reason, or take any medicine, follow your doctor's advice.
At a glance
- Fulvic acid is the fraction of humic substances that stays dissolved at any pH: an operational definition, not one chemical, covering thousands of molecules.
- Laboratories measure it by alkaline extraction, acidification to remove humic acid, sometimes a resin step, then drying, weighing and subtracting ash.
- One published analysis found 21.5 to 36.7 per cent fulvic acid in four batches of raw shilajit and 71.3 to 75.3 per cent in water extracts of the same material.
- A 2025 AOAC study found that 11 of 25 commercial "fulvic acid" products contained no genuine fulvic fraction.
- Human trials gave whole shilajit, were small and mostly in healthy adults, so none isolates fulvic acid; follow your doctor's advice before taking it.
What is fulvic acid?
Fulvic acid is one fraction of humic substances, the organic matter formed from the breakdown and transformation of dead plant tissue. Chemists split humic substances by solubility: humic acid dissolves in alkaline solutions but not acidic ones, while fulvic acid stays dissolved whatever the pH. The definition is a laboratory one, not a chemical formula.
A 2025 paper in the Journal of AOAC International puts it plainly: humic and fulvic acids are "operationally defined based on their solubility in aqueous solutions". The same paper notes that both are complex mixtures of thousands of individual molecules, more than 10,000 in some analyses, mostly between 200 and 800 daltons in molecular weight. So "fulvic acid" names what passes a particular separation, not one substance.
The third fraction, humin, is the part that does not dissolve in water at any pH. A 2012 review of shilajit describes the same three-way split and says all three are found in shilajit preparations. A review of shilajit's chemistry, first published in 2023, found in the literature that more than 80 per cent of shilajit's weight is humic substances, though it also says its full chemical composition "is not known with certainty".
How do laboratories measure fulvic acid in shilajit?
By separating it and weighing it. The usual approach dissolves the sample in alkali, acidifies the extract to about pH 1 to 2 so that humic acid falls out, and keeps what stays dissolved. Some methods then pass that liquid over a resin to separate fulvic acid from the rest. The result is dried, weighed and corrected for mineral ash.
The 2025 AOAC paper calls the material left in solution after acidification the "fulvic fraction". It then separates that further: the part that binds to a type of resin (DAX-8) is called hydrophobic fulvic acid, and the rest is hydrophilic. A standardised method published in the same journal in 2014 works the same way. It was written for humic ores and products, not shilajit, but shows what a careful measurement involves.
- Extract. The sample is dissolved in an alkaline solution, following International Humic Substances Society guidelines.
- Acidify. The extract is made strongly acidic. Humic acid precipitates and is removed; the liquid left is the fulvic fraction.
- Separate. Fulvic acid is separated from the rest of the fulvic fraction by adsorbing it on a non-ionic acrylic ester resin at acid pH.
- Weigh. Humic and fulvic acid are measured by weight on an ash-free basis, so mineral ash is not counted as fulvic acid.
Not every published analysis of shilajit uses all four steps. A 2026 study by the research and development division of Natura Ayur Science, a Bengaluru company, precipitated humic acid at pH 2, then dried the whole remaining solution, weighed it and subtracted the ash. With no resin step, their figures below are not directly comparable with a resin-based measurement.
How much fulvic acid does shilajit contain?
In one published analysis, four batches of raw shilajit gave 21.5 to 36.7 per cent fulvic acid by weight, and extracts made from them gave 71.3 to 75.3 per cent. Products used in clinical trials have been described as standardised to at least 50 or 60 per cent, with no method given.
| Material | Fulvic acid reported | How it was measured | Source |
|---|---|---|---|
| Raw shilajit, four batches | 21.50 to 36.67 % (average 31.10 %) | Gravimetric: humic acid removed at pH 2, solution dried and weighed, ash subtracted; no resin step | Srivastava et al., 2026 (company research division) |
| Water extracts of that shilajit, four batches | 71.28 to 75.34 % (average 73.73 %) | Same method | Srivastava et al., 2026 |
| Branded purified extract used in a US trial | "≥50.0 %" | Not stated in the trial paper | Keller et al., 2019 |
| Resin used in a 2026 pilot study | "standardized to ≥60 %" | Not stated in the trial paper | Yadav et al., 2026 |
In the same study, mineral ash fell from an average of 30.26 per cent in the raw material to 19.90 per cent in the extracts, and the extracts weighed on average 40.75 per cent of the material they were made from.
Two points stand out. Raw shilajit varied between batches by more than 15 percentage points (36.67 − 21.50 = 15.17), using one method in one study. And extracting it with water more than doubled the reported figure (73.73 ÷ 31.10 ≈ 2.4). In this study, figures above 70 per cent came only from extracts.
Why do fulvic acid figures on labels vary so much?
Because the number depends on choices a label may not state: whether the product is raw resin or a concentrated extract, whether the method counts the whole fulvic fraction or only resin-bound fulvic acid, and whether minerals are subtracted. A percentage with no named method cannot be checked against another.
There is a second problem: not everything sold as fulvic acid is. The 2025 AOAC study tested 25 commercial products labelled as fulvic acid and found, on its screening test, that 14 contained a genuine fulvic fraction and 11 did not. The paper does not say that any product tested came from shilajit, but it notes that fulvic products are made from sources including compost, peat, shilajit and brown coal, and that fulvic solutions are easily mimicked by materials such as lignosulfonates and corn steep liquor.
If you are reading a shilajit label or a laboratory report, these are the questions worth asking.
- Does it name the method, and does that method remove humic acid and correct for ash?
- Does it say whether the figure is for raw resin or an extract?
- Is it a result for the batch in your hand, or a claimed specification?
- Does the same report cover heavy metals? Our guide to identifying pure shilajit explains why heavy-metal results matter.
What does the human evidence on shilajit and fulvic acid show?
Very little about fulvic acid itself. The human trials we found gave people whole shilajit products, so any effect cannot be pinned on fulvic acid rather than the minerals and other compounds alongside it. The trials were small, mostly in healthy adults, and one systematic review rated the evidence for one extract as "possibly effective" for a single outcome.
An eight-week randomised, placebo-controlled trial in 63 recreationally active men (Keller et al., 2019) found that, among the stronger half of the men, the higher-dose group lost less strength after a fatiguing exercise test; the lower dose did not differ from placebo. Another eight-week randomised trial in 35 trained young men (Neltner et al., 2024) measured a blood marker of collagen production, not a health outcome. A randomised, placebo-controlled trial in healthy volunteers aged 45 to 55 (Pandit et al., 2016) reported higher total and free testosterone than placebo after 90 days. A 48-week randomised, placebo-controlled trial in 60 postmenopausal women with osteopenia (Pingali and Nutalapati, 2022) reported less loss of bone mineral density with a shilajit extract than with placebo. A 2026 pilot study of 25 men had no placebo group.
A 2024 systematic review of supplements sold to raise testosterone (Morgado et al.) found that most fail to increase total testosterone. It listed one purified shilajit extract as "possibly effective" for men with late-onset hypogonadism. A 2011 review in the Journal of Ethnopharmacology concluded that shilajit "lacks scientific evaluation and systematic documentation" and that its bioactivity "lacks substantial evidence". A 2014 review notes that "relatively few well-controlled human studies" have been done.
On safety, a 2024 review of heavy metals in shilajit found most reported levels below WHO and FDA limits for herbal medicines, but not all, and warned that taking shilajit "without knowing permissible levels of metals is not safe". Our article on how shilajit resin is used covers the practical side; for your health, follow your doctor's advice.
What do animal and laboratory studies of fulvic acid show?
They show activity in test tubes and animal cells, which is a reason for further research, not evidence of a benefit in people. Fractions of shilajit extract have bound immune proteins in the test tube and altered mouse immune cells in culture. None of this tells you what eating shilajit does to a person.
A 2009 study from Montana State University found that fractions of commercial shilajit extract bound complement, part of the immune system, and that this activity correlated with their carboxylic group content. A 2003 study found that some fulvic acid fractions from mumie, another name for shilajit, increased reactive oxygen species and nitric oxide in mouse immune cells. The 2014 review notes a growing number of animal and test-tube studies of shilajit, against relatively few well-controlled human ones.
The short version
Fulvic acid is the part of humic substances that stays dissolved at any pH: a fraction defined by a laboratory procedure, not one chemical. Methods differ in what they count, so a label figure means little without the method and whether it describes raw resin or an extract. One analysis found 21.5 to 36.7 per cent in raw shilajit and 71.3 to 75.3 per cent in extracts. Human trials of shilajit are small and test whole products, so follow your doctor's advice before taking it for any health reason.
Sources
Further reading behind the figures above. Himdhara's own numbers — yields, batch results — come from our production records and the batch reports on the lab reports page.
- Vialykh EA, Buckley S, et al. (2025). Use of a Spectrophotometric Method for the Detection of Adulterants in Commercial Fulvic Acid Products. Journal of AOAC International.
- Lamar RT, Olk DC, Mayhew L, Bloom PR (2014). A new standardized method for quantification of humic and fulvic acids in humic ores and commercial products. Journal of AOAC International.
- Srivastava J, Chaturvedi S, et al. (2026). Evaluation of organic and inorganic constituents of naturally occurring shilajit: augmentation of fulvic and humic acid and its fingerprinting. Journal of Pharmacognosy and Phytochemistry.
- Wilson E, et al. (2011). Review on shilajit used in traditional Indian medicine. Journal of Ethnopharmacology.
- Hussain A, Saeed A (2024). Hazardous or Advantageous: Uncovering the Roles of Heavy Metals and Humic Substances in Shilajit (Phyto-mineral) with Emphasis on Heavy Metals Toxicity and Their Detoxification Mechanisms. Biological Trace Element Research.