An extensive review of commercial CBD products shows that inaccurate content labels remain a widespread problem. Of 937 products analyzed, only 31.3 percent contained a CBD amount that was within ten percent of what the manufacturer stated on the package.
The findings mean that more than two in three products failed the commonly used threshold for acceptable deviation. The results were especially poor for topical products and products intended for vaping. Several studies also found THC, synthetic cannabinoids, heavy metals, pesticides and residues of solvents.
Researchers reviewed 28 earlier studies
The review was carried out by researchers at the University of Malta and published in the journal Phytochemistry Letters. The team compiled results from 28 peer-reviewed laboratory studies published between 2017 and 2025.
The studies covered several types of products, including oils, tinctures, edibles, vape products and products applied to the skin. A total of 937 products were included in the part of the material where a deviation of no more than ten percent was used as the threshold for correct labeling.
This was therefore not a single laboratory test of products from one country, but a broad review of analyses from several geographic markets.
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Oils performed best — topical products worst
Oils and tinctures were the product category most likely to contain roughly the amount of CBD listed on the label. In that group, 41.3 percent, or 124 of 300 products, met the threshold for correct labeling.
Edible products performed almost as well. Of 262 products tested, 106 were correctly labeled, which equals 40.5 percent.
The result was significantly worse for vape products. Only 28 of 115 products, or 24.3 percent, contained a CBD amount that matched the label.
By far the worst results were seen in creams, balms and other preparations intended for skin application. Only 36 of 260 products met the threshold, equivalent to 13.8 percent. That means nearly nine in ten topical products were mislabeled.
Some products lacked the CBD they claimed to contain
The problems were not limited to minor concentration differences. The material included products where the declared CBD amount could not be confirmed, and products that contained no CBD despite the compound being listed on the package.
The researchers also identified major variation within the same product. This can mean that the contents are not evenly distributed in a cream, edible or liquid. Two equal doses from the same package may then contain different amounts of CBD.
Such variation makes it difficult for consumers to know how much CBD they are actually using. That is especially problematic when products are bought for a repeated and predictable effect.
THC and other undeclared substances were found
Several of the compiled studies also detected substances that did not match the product labels. Among the findings were delta-9-THC and synthetic or semisynthetic cannabinoids.
Heavy metals, pesticides and solvent residues were also reported. In some cases, the levels exceeded legal or toxicological limits.
Undeclared THC can mean that consumers ingest a psychoactive substance without knowing it. It can also create problems in drug testing or in countries where even very small amounts of THC are subject to strict rules.
The findings of synthetic cannabinoids are particularly concerning because these substances can have very different properties and risks from naturally occurring CBD.
Product form affects quality
The differences between product categories suggest that the manufacturing process plays a major role. In general, it is easier to mix and analyze CBD in a homogeneous oil than in a skin cream, a candy product or a liquid with several ingredients.
Each product type also places different demands on sampling and laboratory analysis. A method that works well for oil does not necessarily produce equally reliable results for chocolate, gummies, cosmetics or vape liquids.
The researchers therefore call for separate quality and analysis requirements for different product categories, rather than using the same test methods and tolerance limits for every type of product.
Weak oversight in a growing market
CBD is now sold in everything from dietary supplements and food products to cosmetics and inhalation products. Unlike approved medicines, many of the products are sold in markets where oversight, laboratory testing and label requirements vary widely.
The review shows that the problems recur in studies from several countries over a period of almost a decade. That suggests the mislabeling is not only the result of a few unscrupulous manufacturers, but also of more fundamental weaknesses in standardization and regulatory oversight.
The researchers recommend harmonized analysis standards, mandatory contamination testing and more extensive control of products already on the market.
They also note that the earlier studies used different analytical methods, sampling strategies and thresholds for what counted as correct labeling. The results therefore cannot be used to judge each individual brand. Even so, the overall picture is clear: consumers today cannot assume that a CBD product contains the amount — or only the substances — listed on the package.
Source
Review: Only three in ten CBD products contain the right amount
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