Adulterated and Mislabeled Cannabinoid Products

A "mislabeled" product contains something different from what the label says. An "adulterated" product has been contaminated or has an added substance that should not be there. Both problems have been documented in cannabinoid products. This page summarizes what testing studies and regulators report. It is education only. It names no brands and gives no buying advice.

How evidence is labeled here. Established means consistent findings across several studies. Mixed means findings differ. Marketing claim means a statement from a seller that has not been proven. Insufficient evidence means too little data.

Why consumer products are different from medicines

The FDA has approved one prescription CBD medicine (Epidiolex) for specific seizure disorders. [1] Over-the-counter CBD products are not held to the same checks. NCCIH says they may contain more or less CBD than stated on their labels, and may contain contaminants such as THC, because oversight is less rigorous than for prescription drugs. [2] The FDA says it has tested the cannabinoid content of some products and found that many did not contain the CBD levels they claimed, and that it is investigating reports of unsafe levels of contaminants such as pesticides, heavy metals and THC. [1]

What laboratory studies found

Tinctures, gummies, vapes and topicals. A 2024 study bought 202 CBD products in the United States (100 tinctures, 48 gummies, 34 vape products, 20 topicals). 74% deviated from their stated CBD amount by at least 10%, and 26% did not meet the definition for the type claimed on the package (full spectrum, broad spectrum or isolate). [3] Heavy metals were found in 44 of the 202 products, with lead the most frequent. Solvents left over from manufacturing (hexane, xylenes, methanol) were detected in 181 products, and 26 of 232 pesticides tested were found in 30 products. [3] Only a small share exceeded regulatory limits (3% of heavy metal findings, 1% of solvent findings and 1% of pesticide findings), so "detected" and "above a limit" are different things. [3] Label: established for label inaccuracy; mixed on how often contaminants reach harmful levels.

Gummies. A 2025 analysis of 56 CBD gummies found 70% differed by more than 10% from the CBD amount listed. [4] Delta-9 THC was present in 39% of them, and 16% contained more than 0.4 mg per gummy. [4] Gummies within the same bottle varied too. [4] The authors noted occasional delta-8 THC was also found, often unknown to the consumer. [4]

These are samples chosen by the researchers. Results do not describe every product, and they do not mean any one product is good or bad. For how to read a lab report, see how to read a cannabis COA and product quality and certificates of analysis. For specific contaminants see pesticides, heavy metals and residual solvents.

Why unlisted THC matters

Unexpected THC matters for people who must avoid it for health, work or legal reasons. See cannabis, CBD and drug testing. NCCIH also says CBD may produce psychotic effects or cognitive impairment in people who also regularly use THC. [2]

Adulterated THC vape cartridges

In the 2019 EVALI outbreak, the FDA says THC-containing vaping products, particularly from informal sources, were linked to most cases and vitamin E acetate was strongly linked. [5] In its preliminary lab analysis, about half of THC product samples contained vitamin E acetate as a diluent, and about 29% contained another diluent such as medium chain triglycerides. [5] Label: evidence of harm. See smoking and vaping cannabis risks.

Delta-8 THC and similar converted products

The FDA says the natural amount of delta-8 THC in hemp is very low and that extra chemicals are needed to convert other cannabinoids, like CBD, into it. [6] It raises concerns that some manufacturers may use potentially unsafe household chemicals, that additional chemicals may be used to change color, and that the final product may have harmful by-products. [6] The FDA also says these products may be labeled simply as "hemp," which can mislead people who associate hemp with non-psychoactive, and that they have not been evaluated or approved for safe use. [6] See delta-8 THC and HHC.

Unproven claims

The FDA says it has sent warning letters to companies illegally selling CBD products that claimed to prevent, diagnose, treat or cure serious diseases such as cancer. [7] Claims like these are marketing claims unless backed by approved-medicine data. The FDA also says that, under US federal law (read 2026-10-22), adding CBD to food or labeling it as a dietary supplement is illegal. [1] This is not legal advice; laws differ by place and change. See consumer CBD product rules.

What a label can and cannot tell you

• A label percentage or milligram figure is a statement by the seller, not an independent measurement.
• "Hemp-derived," "lab tested" or "natural" do not show a product is accurate or clean.
• A certificate of analysis helps only if it matches the batch and comes from an independent laboratory.

For general guidance see product quality and contamination and unsafe products and warnings. People who have a bad reaction can talk with a health professional and review side effects and reporting.