Fulvic Acid in Shilajit: Which Test Can You Trust?

If you have ever compared Shilajit products, you may have noticed something strange.

One brand proudly claims “80% fulvic acid”, another lists 50%, while someone else insists on 30 to 40%. How can they all be talking about the same thing and yet be so far apart?

The short answer is this: it is not just about the Shilajit. The figures depend heavily on how the fulvic acid was measured in the laboratory.

Different testing methods produce very different results, sometimes dramatically so. What looks like a superior product on paper may simply have been tested using a broader, looser or more generous method.

This is one of the main reasons why understanding how Shilajit is properly tested is essential when comparing products. It helps you identify which brands are being transparent, which may be leaning on inflated numbers, and why choosing properly tested, transparently sourced Shilajit actually matters.

Quick answer

The most meaningful method currently available for testing fulvic acid in Shilajit is an IHSS-aligned separation method, such as the validated Lamar method or the ISO 19822:2018 procedure developed from it.

These methods separate humic acid and hydrophobic fulvic acid from the wider Shilajit matrix before measuring them on a dry, ash-free basis.

Other techniques, including total organic carbon, UV-Vis spectroscopy and titration, can provide useful analytical information. However, they do not necessarily measure the same fraction and should not be treated as directly equivalent to an ISO 19822 result.

Depending on the sample, preparation and calculation used, broader methods can produce fulvic acid figures 20 to 50% higher than a stricter separation-based method, and sometimes more.

This means the biggest percentage on a label is not automatically the best result.

Sometimes it is simply the most generous test.

Can Shilajit really contain 70% or 80% fulvic acid?

A claim of 70% or 80% fulvic acid should immediately make you ask questions.

Shilajit is not purified fulvic acid. It is a naturally complex organic-mineral material containing multiple humic fractions, trace elements, mineral matter and smaller organic compounds.

For a full-spectrum Shilajit resin, it is difficult to reconcile a claim that 80% of the entire product is fulvic acid with everything else the resin is supposed to contain.

That does not mean every high result is invented.

A very high percentage may reflect:

• A broad definition of fulvic acid

• A total carbon measurement

• A colour or absorbance-based estimate

• The complete acid-soluble fraction

• A result calculated on a dried basis

• A heavily purified or concentrated product

• A conversion formula that includes compounds beyond hydrophobic fulvic acid

The important point is that these results are not directly comparable.

An 80% result from a broad carbon or titration-based method does not automatically represent twice as much meaningful fulvic acid as a 40% result produced using ISO 19822.

For a deeper look at the marketing behind these claims, read why a high fulvic acid percentage can be a red flag.

Why fulvic acid results vary so much

Fulvic acid is not one simple, isolated molecule.

It is a broad name applied to a complex fraction of naturally occurring organic material. Before a laboratory can publish a fulvic acid percentage, it must decide:

• How the Shilajit will be extracted

• What will be included in the fulvic fraction

• Which compounds will be excluded

• Whether the fraction will be physically separated

• Whether the result will be inferred from carbon, colour or acidity

• Whether mineral residue will be removed

• Whether the figure will be reported as sold, on a dry basis or on an ash-free basis

Change any of these decisions and the final percentage can change with it.

This is why two laboratory reports can show completely different figures without either laboratory necessarily making a basic calculation mistake.

They may simply be measuring different things and calling them by the same name.

Fulvic acid testing methods compared

Testing method	What it measures	Main problem	How useful is it for a fulvic acid claim?
TOC	Total organic carbon	Cannot identify which compounds supplied the carbon	Limited without prior fractionation
UV-Vis or colorimetry	Light absorbed by an extract	Other light-absorbing compounds and calibration choices can influence the result	Limited unless specifically validated
Titration	Acid-base behaviour	Does not directly weigh isolated hydrophobic fulvic acid	Limited for a percentage claim
Lamar method	Separated humic acid and hydrophobic fulvic acid	More complex and time-consuming	Highly relevant
ISO 19822:2018	Standardised separation and ash-free gravimetric measurement	Measures a specifically defined hydrophobic fraction	Our preferred benchmark
HPLC, HPTLC, FTIR and NMR	Molecular markers, profiles and structural characteristics	Not automatically equivalent to an ISO fulvic acid percentage	Valuable supporting methods

TOC: Total Organic Carbon

TOC is one of the easiest methods to understand.

It measures the total organic carbon in a sample or prepared extract. What it does not do on its own is identify which compounds supplied that carbon.

That distinction matters.

Shilajit contains carbon from fulvic compounds, humic substances and numerous other organic components. Unless the relevant fulvic fraction has already been separated, a TOC result cannot determine how much of that carbon came specifically from hydrophobic fulvic acid.

On the plus side, TOC is widely available, relatively quick and capable of producing impressive-looking percentages.

The problem is that those percentages can be misleading when they are presented as a direct measurement of fulvic acid.

If everything organic in the sample contributes to the result, you are not measuring fulvic acid alone. You are measuring a much broader pool of organic material and applying a fulvic acid label to it.

Depending on the conversion and sample preparation, this can produce figures 20 to 50% higher than a stricter fractionation method.

Verdict

TOC is useful for measuring organic carbon.

Without prior separation and proper validation, it is not a reliable way to prove that a Shilajit product contains a specific percentage of fulvic acid.

If a brand uses a TOC-derived figure, it should explain:

• Whether the fulvic fraction was isolated first

• How the carbon result was converted into fulvic acid

• Which reference material was used

• Whether the method was validated for Shilajit

Without those details, treat the percentage cautiously.

UV-Vis spectroscopy

UV-Vis spectroscopy measures how much ultraviolet or visible light a prepared sample absorbs.

It is fast, widely available and relatively inexpensive. From a commercial perspective, that makes it attractive. A sample can be tested quickly and converted into a neat percentage for a certificate or product label.

The weakness is specificity.

Shilajit is naturally dark and chemically complex. Multiple compounds within an extract can absorb light at the wavelength being measured.

Results can be influenced by:

• The extraction process

• The wavelength selected

• The calibration standard

• Differences between the standard and the Shilajit sample

• Other light-absorbing compounds in the extract

• The natural colour of the source material

A comparative study of humic products found that a colorimetric method substantially overestimated humic acid when compared with a classical separation-based method.

That study examined humic acid rather than finished Shilajit fulvic acid, so the exact figure cannot simply be copied across. However, it demonstrates the wider problem clearly.

A dark, complex extract producing a strong optical response does not prove that every substance responsible for that response is fulvic acid.

Verdict

UV-Vis can be useful for characterisation, comparisons and properly validated targeted assays.

It is less convincing when a complex Shilajit extract is measured against a generic standard and the result is presented as a definitive fulvic acid percentage.

Measuring colour is not the same as physically isolating the fraction you are claiming to measure.

The Lamar method

The Lamar method has sometimes been confused with oxidation or UV-Vis techniques.

That is incorrect.

The validated method developed by Lamar and colleagues uses:

1. Alkaline extraction of the humic substances

2. Acidification to precipitate humic acid

3. Separation of hydrophobic fulvic acid using an adsorption resin

4. Elution and recovery of the separated fraction

5. Dry, ash-free gravimetric measurement

In simple terms, it separates the relevant fractions before weighing them.

The method was developed using fractionation principles aligned with those used by the International Humic Substances Society. It was evaluated for recovery, precision, detection limits, ruggedness and selected interferences.

It later formed the analytical basis for ISO 19822:2018.

That places the Lamar method and ISO 19822 in the same family of separation-based analysis. They are not competing approaches where Lamar sits somewhere between TOC and ISO.

The Lamar method is the scientific foundation from which the ISO procedure developed.

Verdict

A credible, validated and highly relevant method.

Unlike TOC, colour measurement or titration, it does not simply assume that every organic, light-absorbing or acidic component represents fulvic acid.

It separates a defined hydrophobic fulvic acid fraction before measurement.

Titration

Titration is a classic laboratory technique in which acids and bases are used to study chemical reactions.

Within humic-substance research, titration can be used to examine acid-base behaviour and estimate reactive groups, including carboxylic and phenolic groups.

That is legitimate chemistry.

The problem starts when this acid-base response is turned into a headline percentage and presented as though it directly represents the mass of hydrophobic fulvic acid in the original Shilajit.

Titration does not physically isolate and weigh the ISO-defined fulvic fraction.

The result can depend heavily on:

• The extraction method

• The assumed chemical model

• The selected end points

• Which acidic groups are included

• Other acids within the sample

• The formula used to calculate a percentage

The commercial appeal is obvious.

Titration is relatively simple, affordable and can produce extremely high numbers that look fantastic on a label.

From a marketing perspective, 80% fulvic acid sounds better than 40%.

From an analytical perspective, the two figures may not be measuring the same thing at all.

Verdict

Titration is useful for studying acid-base properties.

It is not directly interchangeable with a separated, ash-free hydrophobic fulvic acid result.

If a brand promotes a very high titration-derived percentage, it should publish the complete method and explain exactly what was measured.

ISO 19822:2018

ISO 19822:2018 is our benchmark.

The standard provides an internationally recognised procedure for measuring humic acid and hydrophobic fulvic acid in applicable materials, including geological deposits.

It uses:

• Alkaline extraction

• Acid precipitation of humic acid

• Resin separation of hydrophobic fulvic acid

• Dry, ash-free gravimetric measurement

The key difference is simple.

It separates before it quantifies.

TOC measures total carbon.

UV-Vis measures absorbance.

Titration measures acid-base behaviour.

ISO 19822 attempts to isolate and measure a clearly defined hydrophobic fulvic acid fraction.

This stricter definition excludes many of the additional substances that can contribute to broader carbon, colour or acid-soluble measurements.

That is why ISO figures may be lower than the percentages advertised by brands using other techniques.

The lower result is not automatically a weakness.

It can be evidence that the method is counting less of what should not have been called fulvic acid in the first place.

Is ISO 19822 specifically a Shilajit standard?

No.

Its formal scope includes humic materials used in fertiliser ingredients, soil amendments and geological deposits. It was not written as a dedicated supplement standard.

However, Shilajit is a geological organic-mineral material containing humic substances.

ISO 19822 provides a far more clearly defined and standardised measurement than simply estimating fulvic acid from carbon, colour or titration response.

For that reason, we consider it the strongest available benchmark for measuring hydrophobic fulvic acid in Shilajit.

Does ISO 19822 have limitations?

Yes.

Every analytical method has limitations.

ISO 19822 measures an operationally defined hydrophobic fulvic acid fraction. It does not measure every acid-soluble compound that might be loosely described as “fulvic”.

Some potential interfering materials may also require supplementary screening.

Being open about these limitations does not weaken the method.

It strengthens it.

ISO 19822 clearly defines what is being measured, how it is separated and how the result is calculated.

Verdict

The most credible and comparable benchmark currently available for Shilajit brands making a hydrophobic fulvic acid percentage claim.

It takes longer, costs more and may produce a less glamorous number.

We would rather publish a meaningful number than win a percentage competition built around incompatible tests.

How to read an ISO 19822 result

Even an ISO result needs context.

Before comparing two products, check:

• Whether both results were produced using the same method

• Whether both samples were tested in the same physical form

• Whether the result is reported as sold, on a dry basis or on an ash-free basis

• Whether the report identifies hydrophobic fulvic acid specifically

• Whether the sample can be traced to the product batch

• Whether the complete report is available

This is why understanding how to read a Shilajit lab report matters.

A laboratory certificate is only as useful as your ability to interpret the method, units, sample details and reporting basis behind the headline number.

What About Eurofins and Other Big Laboratories?

Eurofins is probably the laboratory name you will see most often when comparing Shilajit brands.

Brands place the Eurofins name prominently on product pages, certificates and advertising because it creates an immediate impression of authority. To the average customer, “tested by Eurofins” sounds like the final word on quality.

But the laboratory name only tells you who carried out the analysis. It does not tell you what was measured or which method the brand commissioned.

This matters because some of the 70% to 80% fulvic acid claims promoted by Shilajit brands are supported by Eurofins reports using spectrophotometric or other non-ISO methods.

The report may be genuine, and Eurofins may have carried out the requested procedure correctly. That still does not make the result directly comparable with hydrophobic fulvic acid measured using ISO 19822.

Large contract laboratories offer many different analytical methods. The brand, manufacturer or supplier commissioning the test normally selects which procedure is used.

This could include:

• Spectrophotometric analysis

• UV-Vis or colorimetric testing

• Total organic carbon

• A pharmacopoeial procedure

• A laboratory-developed method

• ISO 19822

• Another extraction and calculation method

These tests can produce very different percentages because they do not all define or measure fulvic acid in the same way.

This is the detail that disappears when a brand simply says:

“Tested by Eurofins.”

The name sounds impressive, but it does not answer the most important question:

Which method did Eurofins use?

If the report states that the result was obtained using a spectrophotometric method, it should not be compared directly with an ISO 19822 hydrophobic fulvic acid result. They are different tests measuring differently defined fractions.

A Eurofins logo does not make a broad method more specific, and it does not prove that 70%, 75% or 80% of the complete Shilajit resin is ISO-defined hydrophobic fulvic acid.

Before accepting the headline percentage, check:

• Whether ISO 19822:2018 is specifically named

• Whether the result is described as hydrophobic fulvic acid

• Whether the method is spectrophotometric, gravimetric, carbon-based or titrimetric

• Whether the result is reported as sold, on a dry basis or on an ash-free basis

• Whether the report can be traced to the finished product and current batch

For a complete explanation of these details, read how to read a Shilajit lab report.

The bottom line is simple.

Eurofins may be a respected laboratory, but the method still determines what the number means.

The laboratory name may be the same.

The test is not.

Other testing methods you may hear about

Several other analytical techniques appear in discussions about Shilajit and humic substances.

They can be valuable, but they answer different questions.

E4/E6 absorbance ratio

The E4/E6 ratio compares absorbance at selected wavelengths.

It is mainly used to compare optical characteristics within humic materials. It does not directly isolate or weigh fulvic acid.

HPLC and HPSEC

Chromatographic methods can separate and quantify selected marker compounds or method-defined fractions when suitable standards and validation are available.

They can tell you a great deal about a Shilajit sample.

They do not automatically produce a percentage equivalent to ISO 19822 hydrophobic fulvic acid.

HPTLC

HPTLC can be useful for sample profiling, marker identification and detecting unusual or adulterated material.

Quantitative methods have been proposed, but the result remains dependent on extraction, calibration and the reference standard used.

FTIR and NMR

FTIR and NMR are valuable tools for structural characterisation, authenticity work and comparing the chemical profiles of different materials.

They are supporting analytical tools rather than direct substitutes for an ISO 19822 result.

Ash content and residue on ignition

Ash testing measures the inorganic residue left after a sample is heated.

It is not a standalone fulvic acid test.

However, ash correction is important within separation-based gravimetric methods because residual mineral matter must not be counted as humic or fulvic acid.

Fulvic acid is not the whole of Shilajit

The supplement industry has turned fulvic acid into the headline number because percentages are easy to sell.

Shilajit is more complicated than that.

A full-spectrum resin also contains humic acid, mineral matter, trace elements and numerous smaller organic components.

Aggressive purification may increase the measured fulvic acid percentage while reducing other parts of the natural matrix.

That does not automatically make the product better or worse, but it does mean the fulvic acid figure needs to be read in context.

Our view is that a complete profile is more useful than one isolated number.

That includes:

• Hydrophobic fulvic acid

• Humic acid

• Mineral and trace-element composition

• Heavy metals

• Microbiology

• Solvent residues

• PAHs

• Mycotoxins where appropriate

• Water content

• Batch traceability

You can read more about why humic acid matters in full-spectrum Shilajit.

Why One Life Foods uses ISO 19822

We are not interested in producing the largest possible percentage for the front of a label.

We are interested in understanding what is actually in our Shilajit.

That is why we use an IHSS-aligned analytical approach implemented under ISO 19822:2018.

It is slower and more expensive than many broad screening methods.

It can also return a lower percentage.

We accept that.

A premium Shilajit product should be able to stand up to a stricter test. It should not need an inflated headline number to appear valuable.

We also publish the wider composition because Shilajit is not simply a delivery system for fulvic acid.

You can review how we test our Shilajit and see the results from each origin.

Our current results demonstrate why context matters. Different origins have different balances of fulvic acid, humic acid, minerals and water content, even when the same overall analytical approach is used.

That natural variation tells you more than a suspiciously neat percentage repeated across every batch and every source.

So, which fulvic acid test is best?

If the goal is meaningful and comparable measurement, ISO 19822:2018 or the validated Lamar method on which it was based stands above broad TOC, colour-based and titration-derived estimates.

That does not mean the other laboratory techniques are useless.

It means they should be used for the questions they are capable of answering.

TOC measures organic carbon.

UV-Vis measures optical absorbance.

Titration measures acid-base behaviour.

ISO 19822 separates and measures a defined hydrophobic fulvic acid fraction.

Those are not the same result.

When a brand claims 70% or 80% fulvic acid, do not be blinded by the size of the number.

Ask:

• Which method was used?

• Was the fulvic fraction physically separated?

• What basis was the result reported on?

• Can you see the complete laboratory report?

• Can the report be traced to the batch being sold?

• What else does the testing show?

These questions will tell you far more about quality than the percentage alone.

For a broader checklist, read what to look for when choosing Shilajit.

The bottom line

Fulvic acid is one of the most discussed components of Shilajit, but how it is measured matters just as much as how much is claimed.

TOC, UV-Vis and titration can produce large and impressive-looking figures.

ISO 19822 uses a stricter, separation-based approach that measures a clearly defined hydrophobic fulvic acid fraction.

It may not produce the biggest number.

It produces the number we would rather stand behind.

When you see a major claim backed by a “laboratory test”, ask which method was used.

If the brand cannot tell you, the percentage does not tell you very much either.

Explore the full Shilajit Guide

References

1. International Organization for Standardization. ISO 19822:2018 specifies analysis of humic acids and hydrophobic fulvic acids in applicable dry and liquid materials, including geological deposits.

2. Lamar RT, Olk DC, Mayhew L, Bloom PR. A New Standardized Method for Quantification of Humic and Fulvic Acids in Humic Ores and Commercial Products. Journal of AOAC International. 2014;97(3):721-730.

3. Lamar RT, Talbot KH. Critical Comparison of Humic Acid Test Methods. The study found substantial overestimation from the evaluated colorimetric and CDFA procedures compared with the classical method.

4. Ritchie JD, Perdue EM. Proton-binding Study of Standard and Reference Fulvic Acids, Humic Acids and Natural Organic Matter. The research used acid-base titration to examine proton-binding and functional-group properties.

Written by

Written by Chris Simon, Founder of One Life Foods.

Chris has worked in the supplement industry since 2009 and is known for seeking out exceptional ingredients, products and formulations. Read more about Chris and the story behind One Life Foods.