Heavy metals and Prop 65: a buyer's guide for Ayurvedic botanicals
By the IndoFolk Wellness Care Team | Last reviewed October 2026
Quick answer: For Ayurvedic botanicals sold in the US, test every lot for lead, cadmium, arsenic and mercury by ICP-MS, then convert the results to micrograms per day at your label's maximum serving. Compare that figure with California's Prop 65 safe harbour levels (lead 0.5 µg/day) and USP <2232> limits (lead 5 µg/day). For EU products, check concentration limits in Regulation (EU) 2023/915 as well.
Heavy metals are one of the most visible compliance risks for brands selling Indian botanicals in the US. Several US brands selling Ayurvedic botanicals received California Prop 65 lead notices in 2025–26, and our own market research counted about six 2026 notices naming psyllium products for lead alone. Roots, barks and powders take up metals from soil, so the question is not whether metals are present but whether you have measured them, per lot, against the right limit.
Which heavy metals matter, and why do botanicals carry them?
Four elements dominate supplement specifications: lead, cadmium, arsenic and mercury. They are the elements covered by USP general chapter <2232> for dietary supplements, and they are the ones regulators and Prop 65 enforcers focus on.
Botanicals can pick them up from soil, irrigation water, processing equipment and dust during drying. Root and rhizome ingredients sit in soil for a full season, and powders concentrate whatever was in the plant. That is why a supplier's "heavy metals: complies" from last year tells you little about this lot.
How do Prop 65, USP <2232> and the EU limits compare?
The three frameworks measure different things. Prop 65 and USP <2232> set daily exposure levels; the EU sets concentration limits in the product as sold.
Element | Prop 65 safe harbour (OEHHA) | USP <2232> daily limit | EU 2023/915, food supplements |
|---|---|---|---|
Lead | 0.5 µg/day (MADL); 15 µg/day (NSRL, oral) | 5 µg/day | 3.0 mg/kg |
Cadmium | 4.1 µg/day (MADL, oral) | 5 µg/day | 1.0 mg/kg (3.0 mg/kg if ≥80% dried seaweed) |
Inorganic arsenic | 10 µg/day (NSRL, non-inhalation routes) | 15 µg/day | No specific food-supplement limit found |
Mercury | No safe harbour level found on OEHHA's current table | 15 µg/day (total); 2 µg/day (methylmercury) | 0.10 mg/kg |
Two points stand out. First, for lead, the Prop 65 MADL is ten times stricter than the USP daily limit, so a product can meet USP and still need a Prop 65 warning. Second, Prop 65 is a warning law, not a ban: if expected exposure exceeds the safe harbour level, the business must give a clear and reasonable warning or face enforcement.
How do you turn a lab result into µg/day?
Labs report metals in parts per million (ppm, equal to µg/g). To compare with a daily limit, multiply by the maximum daily serving on your label:
µg/day = result (µg/g) × maximum daily serving (g)
Here is what the daily limits mean as concentrations at two example serving sizes. These are simple conversions of the published limits, not regulatory values in themselves.
Limit | At 1 g/day serving | At 5 g/day serving |
|---|---|---|
Prop 65 lead MADL (0.5 µg/day) | 0.5 ppm | 0.1 ppm |
USP <2232> lead (5 µg/day) | 5 ppm | 1 ppm |
Prop 65 cadmium MADL (4.1 µg/day) | 4.1 ppm | 0.82 ppm |
USP <2232> cadmium (5 µg/day) | 5 ppm | 1 ppm |
Prop 65 inorganic arsenic NSRL (10 µg/day) | 10 ppm | 2 ppm |
USP <2232> inorganic arsenic (15 µg/day) | 15 ppm | 3 ppm |
The larger the serving, the tighter the ppm target. Powders taken by the teaspoon, such as psyllium or turmeric, face far tighter targets than a 500 mg capsule. Set your raw-material specification from your finished-product serving, then work backwards to account for every ingredient in the blend.
What does a credible heavy-metals test look like?
Method: ICP-MS (inductively coupled plasma mass spectrometry) is the usual technique. USP <2232> relies on the instrumental procedures in USP <233>, which include ICP-MS and ICP-OES.
Arsenic speciation: Labs often test total arsenic and assume it is all inorganic. Under USP <2232>, if total arsenic exceeds the inorganic limit, a speciation test is needed to show compliance.
Reporting: Results per element, with units, limits of quantification and the method reference. "Not detected" is meaningful only if the detection limit is low enough for your serving size.
Laboratory: An accredited laboratory (ask for its ISO/IEC 17025 scope covering metals in botanicals), named on the report.
Lot match: The lot number on the lab report matches the CoA and the shipment.
How should you sample each lot?
Metals are not spread evenly through a bag of powder, so how the sample is taken matters as much as the test.
Test every production lot, not just the first order.
Take a composite sample from several bags and positions in the lot, as described in your written sampling plan.
Retain a portion of each composite sample for re-testing and dispute resolution.
Test raw material and finished product. Excipients, capsules and other botanicals all add to the total.
Trend the results. A creeping lead figure across lots is a warning before it becomes a failure.
In the US, 21 CFR 111.70 requires dietary supplement manufacturers to set component specifications, including limits on contamination, so a documented sampling and testing plan is part of basic compliance.
What does the 2025–26 Prop 65 notice trend mean for buyers?
Under Prop 65, private enforcers can sue in the public interest after giving at least 60 days' notice to the business, the California Attorney General and relevant local prosecutors. OEHHA's summary of the law states civil penalties of up to $2,500 per day for each violation. Notices are public and searchable in the Attorney General's 60-day notice database.
The pattern in 2025–26 is clear: lead in botanical powders, including psyllium and Ayurvedic herbs, is a regular target. We do not name the brands involved, and a notice is an allegation, not a finding. The practical lesson is that any product on sale in California can be tested by someone else, so your own per-lot data needs to stand up to scrutiny. If you sell into California, either keep exposure below the safe harbour levels with documented testing, or take legal advice on warnings before launch.
Buyer's checklist: heavy metals in Ayurvedic botanicals
Specification lists lead, cadmium, arsenic (inorganic) and mercury limits, derived from your label's maximum daily serving
Prop 65 exposure calculated if any product will be sold in California
ICP-MS results per lot from an accredited laboratory, with limits of quantification
Arsenic speciation available if total arsenic is near the limit
Composite sampling plan and retained samples for each lot
Finished-product test, not only raw materials
EU concentration limits (Regulation 2023/915) checked for any EU-bound product
Trend log across lots, reviewed before each re-order
For the wider testing picture, including identity and microbiology, see our guide to testing Ayurvedic ingredients for pet products.
Frequently Asked Questions
What is the Prop 65 limit for lead in supplements?
Prop 65 does not set a concentration limit. It sets a safe harbour level for lead of 0.5 µg/day (the maximum allowable dose level for reproductive toxicity). If expected daily exposure from your product exceeds this, a warning is required unless another exemption applies. Convert your lab result to µg/day using your maximum daily serving.
What are the USP <2232> limits for heavy metals?
USP <2232> sets daily exposure limits for dietary supplements of 5 µg/day for lead, 5 µg/day for cadmium, 15 µg/day for inorganic arsenic and 15 µg/day for total mercury, with 2 µg/day for methylmercury. Check the current official USP-NF text before finalising specifications.
What are the EU limits for heavy metals in food supplements?
Regulation (EU) 2023/915 sets maximum levels for food supplements of 3.0 mg/kg lead, 1.0 mg/kg cadmium (3.0 mg/kg for products made at least 80% from dried seaweed) and 0.10 mg/kg mercury. These apply to the product as sold, not per daily dose.
How often should Ayurvedic ingredients be tested for heavy metals?
Every production lot. Metal levels vary with soil, season and processing, so one historic result does not represent a new lot. Test a composite sample by ICP-MS, keep a retained portion, and test the finished product as well as the raw materials.
Work With IndoFolk Wellness
IndoFolk Wellness coordinates sourcing from vetted Indian manufacturers and collects per-lot CoAs, including ICP-MS heavy-metal results, before goods ship. If you want specifications built around your serving size and target market, request a quote or a spec sheet.
Related Reading
Sources
Proposition 65 Frequently Asked Questions, California Attorney General
Commission Regulation (EU) 2023/915 on maximum levels for certain contaminants in food, EUR-Lex
21 CFR 111.70, Requirements to establish specifications, Legal Information Institute (Cornell)
IndoFolk Wellness market research on 2025–26 Prop 65 notices (owner's memo, 2026); individual notices can be verified in the Attorney General's 60-day notice database above
This article is general information, not legal, regulatory or veterinary advice.
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