Knowledge Centre · 9 min read
Heavy Metals in Ayurvedic Medicine: How to Read a Certificate of Analysis
The published evidence on heavy metals in Ayurvedic products, what a certificate of analysis shows, commonly used limits, and how to check one yourself.
A certificate of analysis (COA) is a lab report for one batch of a product. For an Ayurvedic formulation it should show lead, arsenic, cadmium and mercury results against a stated limit, plus identity, pesticide and microbial tests. Check the batch number, the lab, the method and the limit used. If any is missing, ask.
The concern is real, and it is specific
Two studies from the same research group are the reason this question comes up. Saper and colleagues, writing in JAMA in 2004, bought 70 Ayurvedic products from stores in the Boston area and found lead, mercury or arsenic in one in five. In 2008 the same group bought 193 products online, made in the USA and in India, and again found detectable lead, mercury or arsenic in about one in five.
The second study drew a distinction that matters. Products made by Rasa Shastra, the branch of Ayurveda that deliberately incorporates processed metals and minerals (Bhasma), were more likely to contain heavy metals, and at higher concentrations, than herbal-only products. Herbal products were not free of contamination, but their contamination came from soil, water and processing rather than by design.
The honest summary is this: a share of Ayurvedic products sold without testing have contained heavy metals at levels that matter, the risk is concentrated in mineral preparations, and the only way to know about a given product is to test the batch. That is what a certificate of analysis is for.
What a certificate of analysis is
A certificate of analysis (COA) is a laboratory report on one batch of one product. It states what was tested, by what method, what was found, and what limit the result was compared against. A good COA is issued by an independent, accredited laboratory, not by the manufacturer, and is tied to a batch number printed on the pack.
For an Ayurvedic formulation a complete COA covers four things: identity (is the plant material what the label says), heavy metals (lead, arsenic, cadmium, mercury), pesticide residues, and microbial contamination (total bacterial and fungal counts and the absence of specific pathogens). Some add aflatoxins and residual solvents. A certificate that shows only one of the four is a partial answer.
Commonly used limits
Limits are set by different bodies in different units, which is where most confusion comes from. Raw herbal material is usually limited in parts per million (ppm, the same as micrograms per gram). Finished supplements and medicines are usually limited by daily intake in micrograms per day, which depends on how much you take. The table gives the ranges most often used. They are commonly applied limits, not a legal statement for any country.
- Element: Lead
- Commonly used limit in herbal material10 ppm (WHO and Indian ASU herbal limits)
- Commonly used daily intake limit5 to 10 micrograms per day (USP dietary supplement chapters); stricter state-level thresholds exist
- NotesThe most frequently found contaminant
- Element: Arsenic
- Commonly used limit in herbal material3 ppm (Indian ASU herbal limit)
- Commonly used daily intake limit10 to 15 micrograms per day, as inorganic arsenic
- NotesRice-based and some marine ingredients add to background exposure
- Element: Cadmium
- Commonly used limit in herbal material0.3 ppm (WHO and Indian ASU herbal limits)
- Commonly used daily intake limitAbout 5 micrograms per day
- NotesAccumulates in the kidney; leafy and root herbs take it up from soil
- Element: Mercury
- Commonly used limit in herbal material1 ppm (Indian ASU herbal limit)
- Commonly used daily intake limitAbout 15 micrograms per day total; about 2 micrograms per day as methylmercury
- NotesRasa Shastra preparations are the main Ayurvedic source
| Element | Commonly used limit in herbal material | Commonly used daily intake limit | Notes |
|---|---|---|---|
| Lead | 10 ppm (WHO and Indian ASU herbal limits) | 5 to 10 micrograms per day (USP dietary supplement chapters); stricter state-level thresholds exist | The most frequently found contaminant |
| Arsenic | 3 ppm (Indian ASU herbal limit) | 10 to 15 micrograms per day, as inorganic arsenic | Rice-based and some marine ingredients add to background exposure |
| Cadmium | 0.3 ppm (WHO and Indian ASU herbal limits) | About 5 micrograms per day | Accumulates in the kidney; leafy and root herbs take it up from soil |
| Mercury | 1 ppm (Indian ASU herbal limit) | About 15 micrograms per day total; about 2 micrograms per day as methylmercury | Rasa Shastra preparations are the main Ayurvedic source |
The two units can be reconciled with one calculation. A powder at exactly the 10 ppm lead limit, taken at 3 grams a day, delivers 30 micrograms of lead a day, several times the daily intake limits used for supplements. This is why a result that 'complies' with a raw-material limit is not the end of the question. The dose matters, and a good COA or a good physician will do the arithmetic for you.
How to read a COA in five minutes
You do not need a chemistry background to read a certificate, only a few minutes and the pack in front of you. Work down the certificate in the order below, and stop at the first item you cannot find. That missing item is the question to put to the seller before you take anything.
- Find the batch number on the certificate and match it to the batch number on the pack; no match, no certificate.
- Find the laboratory name and check that it is independent of the manufacturer and, ideally, accredited.
- Find the date of testing and confirm it is after the batch was made, not a certificate reused from an earlier batch.
- For each heavy metal, find three things on the same line: the method (ICP-MS is the current standard), the result as a number, and the limit it was compared against.
- Check that the limit is stated in the same unit as the result, and note whether it is a material limit (ppm) or an intake limit (micrograms per day).
- Check that identity, pesticide and microbial tests are present, not only heavy metals.
- Look for a signature or authorization line; an unsigned certificate is a draft.
Red flags on a certificate
The commonest problem is not a failed test but a certificate that does not say enough. 'Complies' or 'Pass' with no number, no method and no stated limit tells you that someone decided the product was acceptable, without telling you against what. 'Below detection limit' without the detection limit stated is the same problem in a different phrase.
Other warning signs: a certificate with no batch number, a certificate issued only by the manufacturer's own laboratory, a certificate that predates the batch, a certificate for a different pack size or formulation, and a company that offers a certificate for 'the product' rather than for the batch you are holding. None of these proves contamination. Each means you do not know.
How Calmvida tests
Every batch Calmvida dispenses or sells is tested by an independent laboratory before release. Identity is confirmed by HPTLC (high-performance thin-layer chromatography), which produces a fingerprint of the plant material against a reference standard. Heavy metals are measured by ICP-MS (inductively coupled plasma mass spectrometry), the method with the lowest detection limits in routine use.
Pesticide residues and microbial contamination are tested on the same batch. The certificate, with batch number, laboratory, method, result and limit, is published on the testing page and shipped with international orders. A batch that fails is not dispensed. The testing page explains each method and what its numbers mean.
This is not a claim that Ayurvedic products in general are safe, or that testing makes any product beneficial. It is a claim about what is in the pack, made checkable. Proof over promise is the whole of the practice's position on this subject.
Plant-only for patients abroad
Because the risk is concentrated in mineral preparations, and because customs authorities in many countries test for exactly these elements, the practice does not ship Bhasma or other mineral-based classical preparations internationally. Patients outside India are prescribed plant-based formulations. Where a case would classically call for a Bhasma, Dr. Arvinder Singh Bali uses a plant-based alternative or advises treatment in Chandigarh.
Plant-based formulations are shipped by tracked courier, typically in 7 to 14 days, within a three-month supply, with customs paperwork and the batch certificate enclosed. Patients are encouraged to read the certificate using the steps above. If anything on it is unclear, ask; the practice would rather answer a question than have a patient take something they do not understand.
Frequently asked questions
Do all Ayurvedic medicines contain heavy metals?
No. Rasa Shastra preparations (Bhasma) contain processed metals or minerals by design. Herbal-only formulations do not, though they can be contaminated from soil, water or processing. The published studies found heavy metals in about one in five untested products, with mineral preparations most affected. A batch certificate of analysis is the only way to know about a specific product.
What is a safe level of lead in a herbal supplement?
Commonly used limits are 10 ppm in raw herbal material and 5 to 10 micrograms of lead per day from a finished supplement, with some regulators setting lower thresholds. The daily figure matters more, because it accounts for how much you take. Multiply the ppm result by your daily dose in grams to get micrograms per day.
What is the difference between a Bhasma and a herbal formulation?
A Bhasma is a classical preparation in which a metal or mineral is processed through repeated purification and incineration with plant materials. It is part of Rasa Shastra and is used under supervision in India. A herbal formulation contains only plant material. Calmvida prescribes plant-based formulations for patients abroad and does not ship Bhasma internationally.
How do I check whether a certificate of analysis is genuine?
Match the batch number to the pack, confirm the laboratory is named and independent of the manufacturer, and check that the test date follows the batch date. Most accredited laboratories will confirm a certificate number if you contact them. A certificate with numbers, methods and stated limits is much harder to fake than one that only says 'Pass'.
Can I have a Bhasma shipped to the USA or the UK?
No. Calmvida does not ship mineral-based classical preparations internationally. Patients abroad receive plant-based formulations with a batch certificate of analysis. Where a case would classically call for a Bhasma, Dr. Bali uses a plant-based alternative or advises treatment in Chandigarh under supervision.
Written and reviewed by
Dr. Arvinder Singh Bali, BAMS
22+ years of clinical practice · 3,00,000+ patients · Government Ayurvedic College, Punjab
Dr. Arvinder Singh Bali is a BAMS qualified classical Ayurvedic physician with over 22 years of clinical practice in Chandigarh, Punjab, India, who has treated 3,00,000+ patients and provides online Ayurvedic consultations through Calmvida to patients in the USA, Canada, UK, Australia, UAE, Russia and Uzbekistan.
Last updated 3 September 2026
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