Recent testing shows a clear link between CBD product quality and customer safety, with most products failing to match their labeled potency and many containing contaminants that could affect health.
Widespread Potency Inaccuracy Across Formats
A 2024 study in Frontiers in Pharmacology examined 202 CBD items, including 100 tinctures, 48 gummies, 34 vape liquids and 20 topicals. The analysis found that 74 % of the samples missed their declared potency by at least 10 %, and the deviations ran both high and low.
Another 26 % did not even meet the basic definition of the product type printed on the package, meaning the label was a weak predictor of what a dose would actually deliver.
Potency errors differed by format. Tinctures rely on an even suspension of CBD in carrier oil; when a batch separates, the concentration at the bottle’s top can differ from that at the bottom. Gummies, made from a slurry before setting, can show wide variation between individual pieces even if the bulk batch tests correctly. Testing a composite of ten gummies often masks the very differences a consumer will encounter.
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Contaminants Detected in Nearly Half of Samples
The same study screened for heavy metals, residual solvents and pesticides. Heavy metals appeared in 44 of the 202 products, while residual solvents were detected in 181 samples. Pesticide analysis identified 26 distinct compounds across 30 items, pointing to cultivation inputs as a primary source.
Hemp plants readily absorb metals and soil residues, so the quality of the growing environment heavily influences final‑product purity. Extraction methods add another exposure point; solvent‑based processes can leave trace residues when the purge step is rushed or equipment is poorly maintained. Those traces concentrate in the distillate that later becomes tincture or gummy stock.
Finished‑goods testing catches problems that raw‑material analysis can miss, because contamination can enter at any stage between harvest and fill. Brands that only test incoming biomass may verify the cheapest input while leaving the actual consumer product unchecked.
Earlier investigations echo these findings. Testing of 84 over‑the‑counter CBD products revealed that only 31 % were labeled accurately within a 10 % margin, and a National Institutes of Health study split the failures evenly, with 26 % containing less CBD than promised and 43 % containing more.
Accurate labeling matters because CBD is pharmacologically active. An FDA‑funded randomized trial gave healthy adults twice‑daily CBD for 28 days and observed raised liver enzymes in 11 % of participants, eosinophilia in 9 %, somnolence in 8 % and diarrhea in 8 %.
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The enzyme elevations reversed after dosing stopped.
CBD also inhibits several cytochrome P450 enzymes, altering how the liver clears many prescription drugs. A patient taking a blood thinner or an anticonvulsant alongside a product containing 40 % more CBD than the label states would receive an unplanned dose change that a prescribing physician could not detect.
Accurate labels are how safety reaches a customer. Anyone following the printed serving size is trusting a number that only laboratory work can support.
Regulatory pressure is increasing, and the market’s reliance on certificates of analysis (CoA) suggests a path forward. If each production lot receives its own CoA tied to a lot number on the package, and the lab is ISO 17025‑accredited, variation can be tracked and recalled quickly.
However, many brands still rely on composite testing, which smooths over lot‑to‑lot differences and may leave consumers exposed to mislabeled or contaminated batches.
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Regulatory Pressure and Industry Response
The FDA has issued more than 200 warning letters to cannabinoid companies since 2019. In April 2025, its Center for Veterinary Medicine wrote to three firms over unapproved cannabis‑derived products sold for uses the agency had never evaluated. Those letters often cite marketing language as frequently as they cite manufacturing practice, reflecting the agency’s focus on therapeutic claims that convert a supplement into an unapproved drug under the Food, Drug, and Cosmetic Act.
Companies that avoid disease claims stay within a regulatory category their quality systems can realistically satisfy. Yet the same documents—CoAs, lot numbers, and lab records—travel beyond the factory. Underwriters, retailers and insurers all request them to assess risk before extending credit, taking inventory or issuing liability coverage.
Full‑panel testing on every lot typically costs a few hundred dollars per batch, but the second cost—product recalls, inventory destruction and lost business—can close companies. The agency has explicitly stated that it has never reviewed the manufacturing of unapproved CBD drug products, and that the effects of consuming products with unsafe pesticide or heavy‑metal levels are unknown.
In practice, a contaminated or mislabeled lot rarely stays contained. Recalls begin with destroyed inventory and laboratory work to determine how far the problem spread. The larger cost arrives afterward, when banks review accounts, retailers suspend items pending re‑qualification, and insurers repricing liability policies.