Heavy Metals in Canadian Legal Cannabis Products Pose Low Health Risk Under Current Regulations | Research

The takeaway

A risk assessment of metals measured in regulated Canadian cannabis products found low health risk from heavy metal exposure, suggesting the Cannabis Act's quality control framework is achieving its safety goals.

Cannabis regulators; consumers concerned about contaminants in legal products.

Low health risk from heavy metals even at 95th percentile daily consumption

What the researchers found

Applying pharmaceutical daily exposure limits to measured metal levels in legal Canadian dried cannabis and vaping liquids showed low risk to health, even for daily or almost-daily consumers at heavy-use levels (95th percentile). The analysis validated that Canada's regulated cannabis supply meets safety standards for elemental impurities.

Why it matters

Heavy metals in cannabis are a recognized consumer concern, especially for inhaled products. This systematic risk assessment provides the first comprehensive evaluation showing that Canada's regulatory framework -- with good production practices and pharmacopoeial impurity limits -- is effectively controlling this risk.

The numbers in context

Analysis covered dried cannabis and cannabis vaping liquids in the Canadian legal market. Used 50th and 95th percentile consumption scenarios. Applied pharmaceutical-grade permitted daily exposure limits. Conclusion: low risk to health for both typical and heavy consumers.

How the study worked

Risk assessment case study using metal levels measured in legal Canadian cannabis products published by Health Canada. Applied pharmacopoeial permitted daily exposure (PDE) standards. Modeled typical (50th percentile) and heavy (95th percentile) daily use scenarios for inhalation exposure.

What this study cannot tell us

Risk assessment is limited to the legal regulated market and does not address illicit products. Uncertainties in exposure characterization for cannabis inhalation (varying amounts consumed, depth of inhalation, frequency) affect precision. The study focuses on elemental impurities only, not other contaminants.

How to read the evidence

Moderate: systematic risk assessment using measured data and pharmaceutical-grade standards, but with acknowledged uncertainties in cannabis-specific inhalation exposure characterization.

When this study was published

2025 risk assessment.

The bigger picture

This study provides a model for other jurisdictions developing cannabis quality standards. The success of Canada's approach suggests that applying pharmaceutical-grade impurity standards to cannabis products is both achievable and effective, though exposure characterization challenges specific to inhalation remain.

Questions still open

How do metal levels in regulated products compare to illicit market products? Are there long-term exposure effects that current pharmaceutical PDE standards may not adequately capture for daily cannabis users?

Common questions

Where do heavy metals in cannabis come from?

Cannabis plants can accumulate metals from soil, water, fertilizers, and growing media. Manufacturing processes for vaping products can also introduce metals. Regulated production practices aim to minimize these sources.

Is legal cannabis safer than illicit cannabis for metal contamination?

This study only evaluated legal products and found them safe. Illicit products are not subject to the same quality controls, testing requirements, or good production practices, so their metal contamination profiles are unknown and potentially higher.

Read the original research

Risk assessment of metals measured in regulated Canadian dried cannabis and cannabis vaping products: case study and perspectives.

Frontiers in toxicology, 7, 1755875

View on PubMed ↗Publisher’s paper ↗

Citation

Achuthan, Sathish; Waye, Andrew; Abramovici, Hanan. (2025). Risk assessment of metals measured in regulated Canadian dried cannabis and cannabis vaping products: case study and perspectives.. Frontiers in toxicology, 7, 1755875. https://doi.org/10.3389/ftox.2025.1755875