The number on the label depends on the method. A 60% claim by one assay and a 20% claim by another can describe the same resin. Method disclosure is the brand-honesty signal that separates serious suppliers from inflated marketing.
Short answer
The "fulvic acid percentage" on a Shilajit label is a measurement that depends entirely on which assay method the lab used. Three common methods (spectrophotometric, gravimetric, AOAC 2014.04) produce systematically different numbers for the same resin — ranges of 40–65%, 15–25%, and 10–20% respectively for authentic material. A brand that prints a percentage without disclosing the method is leaving the most important context off the label.
Why the fulvic acid number is method-dependent
Fulvic acid is not a single molecule — it's a class of small humic-substance molecules with variable structure. The "percentage" on a label is always a measurement of how much fulvic-acid-class material is in the resin or powder, but the boundary of "what counts as fulvic acid" depends on which test you run.
Three common methods, three different answers:
Method 1: Spectrophotometric (UV-Vis colorimetric)
A sample is dissolved in water or buffer, and the absorbance at a specific wavelength is measured. The absorbance is compared to a calibration curve made with a humic-acid reference standard.
- What it measures: Approximate amount of UV-absorbing humic-substance material in the sample
- Typical result for authentic Shilajit: 40–65%
- Why the number is high: The method tends to detect both fulvic and partial humic fractions, especially when the reference standard is also humic-rich. It's an inclusive measurement.
- Where it's used: Most consumer-facing supplement labels. The most common method for marketing claims.
- Where it gets criticized: It's a fast, cheap method, but it's not specific to "fulvic acid" in the strictest chemical sense. The number is real; the interpretation requires context.
Method 2: Gravimetric (acid-base separation)
A sample is dissolved in alkaline solution, then acidified. Humic acid precipitates out (insoluble in acid). The remaining acid-soluble fraction is dried and weighed. That mass is reported as fulvic acid.
- What it measures: The mass of the acid-soluble fraction relative to total sample
- Typical result for authentic Shilajit: 15–25%
- Why the number is lower: This method is strictly limited to the chemically-defined fulvic fraction (acid-soluble at pH 1). It excludes anything that precipitates as humic acid.
- Where it's used: Academic and reference labs. Less common in consumer product testing.
- Where it's strong: Most chemically rigorous of the three methods; produces the "true" gravimetric percentage of fulvic-class material.
Method 3: AOAC 2014.04 (modified Lamar method)
A standardized regulatory method developed for humic-substance analysis, particularly in agricultural and supplement industries. Uses a multi-step extraction and quantification procedure.
- What it measures: Standardized fulvic acid content, designed to be reproducible across labs
- Typical result for authentic Shilajit: 10–20%
- Why the number is lower: Most conservative method; counts only material that meets specific structural criteria
- Where it's used: Regulatory submissions, supplement industry quality programs, fertilizer industry
- Where it's strong: Most defensible for label claims under regulatory scrutiny
Why the same resin can give three different numbers
A representative example. Take a 10g sample of high-quality purified Altai Shilajit resin and have it tested by three different labs using three different methods:
| Method | Result | What it means |
|---|---|---|
| Spectrophotometric (UV-Vis) | 58% "fulvic acid" | Real number; includes both fulvic and some humic fractions |
| Gravimetric (acid-base) | 22% fulvic acid | Real number; only the strictly acid-soluble fraction |
| AOAC 2014.04 | 16% fulvic acid | Real number; conservative regulatory-grade quantification |
All three results describe the same resin. None of them is "wrong." But a label that says "58% fulvic acid" without context could be sitting next to a label that says "16% fulvic acid" without context — and the second product could be the same chemistry.
This is why the supplement category has a category-credibility problem. The number on the label is real but the comparison is broken.
How to read a fulvic-acid claim honestly
Three diagnostic questions to ask of any Shilajit product:
1. What method produced this number? - Stated explicitly (e.g., "X% fulvic acid by AOAC 2014.04") → Higher confidence in the brand's commitment to verifiable claims - Not stated → Probably spectrophotometric; treat the number as a comparison-with-other-spectrophotometric-claims metric, not an absolute - Vague reference to "lab tested" without method → No real claim is being made
2. Is there a per-lot Certificate of Analysis available? - Yes, and it includes fulvic-acid measurement with method disclosed → Strong signal - Yes, but only generic safety panels → Better than nothing, but not specifically substantiating the fulvic claim - No COA available on request → Walk away
3. Is the brand willing to discuss this in writing? - Direct response from sourcing/quality team naming the method and the lab → Strong signal - Marketing-language deflection ("our products are premium tested") → Not a real answer - No response → Walk away
What "high fulvic acid" actually predicts
The honest answer: less than you'd think.
Fulvic acid percentage by any method correlates with the active chemistry, but it's not the only marker that matters. Authentic Shilajit is a system that requires fulvic acid + humic acid + DBPs + minerals working together. A 65% fulvic acid spectrophotometric number from one source can describe better material than a 45% number from another source — or worse material, depending on what else is going on.
What actually matters more than the percentage:
- Authenticated source. Single-origin, named region, traceable supplier.
- DBP presence. The Shilajit-specific signature. (Dibenzo-α-pyrones →)
- Mineral fingerprint. Per-lot characterization of the trace mineral profile. (60+ trace minerals →)
- Heavy metals below USP limits. Per-lot, every time.
- Method-disclosed fulvic claim. Number with context, not number alone.
A brand that hits all five of those is doing real work. A brand that's only marketing on the fulvic percentage is probably hiding context on the other four.
What MYKO does
[The fulvic acid measurement on MYKO Shilajit is reported by method] [verify: which method does MYKO supplier use; align before going public]. Per-lot COAs are available on request. The number on the label is a real measurement; it's also one of several quality markers, not the only one that matters.
For the full quality program, see Quality & Testing.
FAQ
Is a Shilajit with 80% fulvic acid better than one with 25%? Not necessarily. The percentages may be measured by different methods, in which case they're not directly comparable. If both are measured by the same method, higher percentage suggests more fulvic-class material — but it doesn't tell you about humic acid, DBPs, mineral profile, heavy metals, or authentication. Don't rank Shilajit products by a single metric.
Why does my Shilajit label say "65% fulvic acid" but the gravimetric test only shows 20%? Because the 65% is measured by spectrophotometric UV-Vis (the common consumer-facing method) and the 20% is measured by gravimetric acid-base separation (the academic-reference method). Both can be accurate; they're measuring slightly different things.
Is there a "standard" fulvic acid percentage I should expect? No single standard. Authentic purified Shilajit by spectrophotometric method runs 40–65%; by gravimetric, 15–25%; by AOAC 2014.04, 10–20%. Numbers in those ranges are consistent with authentic material when the method is disclosed.
Can a brand cheat by using an inflated method? Yes, and many do. Spectrophotometric numbers are higher and look better on labels; brands that prefer marketing over honesty default to that method without disclosure. The category accepts this practice because consumers don't know to ask. The pushback is asking.
What's the AOAC 2014.04 method? A standardized method developed by AOAC International for humic-substance analysis. It's the most defensible for regulatory and industrial use, and increasingly the standard for serious supplement quality programs. Still relatively uncommon on consumer-facing labels.
Why does the percentage matter if other things matter more? Because most consumers will check the percentage as the first quality signal. The percentage is the easiest comparison metric to look up. Brands know this; they design labels around it. The job of the consumer is to ask the contextual questions the label doesn't answer.
Read next
- Fulvic Acid: The Headline Compound in Shilajit
- Humic Acid: The Supporting Matrix
- How to Spot Counterfeit Shilajit
- Or go upstream: Quality & Testing
References
- Agarwal SP, et al. Shilajit: a review. Phytother Res. 2007. doi.org/10.1002/ptr.2100
- Stohs SJ. Safety and efficacy of shilajit (mumie, moomiyo). Phytother Res. 2013. doi.org/10.1002/ptr.5018
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