The headline finding
In 2022, researchers published an independent analysis of 29 commercially available CBD oil products purchased from UK retailers. The results should concern anyone spending money on CBD.
The mean advertised CBD content across the 29 products was 4.5%. The mean actual measured CBD content was 3.2%. While this difference was not statistically significant across the full sample, individual products showed much larger discrepancies — some contained substantially less CBD than their labels claimed.
This was not an isolated finding. A 2019 analysis by the Centre for Medicinal Cannabis examined a wider sample of UK products and reported that the majority contained less CBD than stated on the label. A 2017 study published in JAMA looking at CBD products sold online found that only 31% were accurately labelled.
What this means, in plain terms, is that when you buy a CBD product in the UK, there is a reasonable chance it does not contain what the label says it contains.
What else they found
CBD content was not the only concern. The 2022 UK analysis also tested for residual solvents and heavy metals — substances that should not be present in a product people consume daily.
Residual solvents. Three of the 29 products contained levels of n-pentane above 1.5 parts per million. One product contained 37,704 ppm of ethanol. Others contained isopropanol, heptane, ethyl acetate, and cyclohexane at detectable levels. These are solvents used in extraction processes that should be removed from the final product.
Heavy metals. Small quantities of lead (0.01 to 0.24 ppm) and arsenic (0.01 to 0.06 ppm) were detected in some products. While these levels were generally low, any detectable level of lead or arsenic in a consumer health product is a data point worth noting — particularly for products marketed for daily use.
THC and CBN. Some products contained detectable levels of THC or CBN, which are controlled substances in the UK. While the quantities were small, their presence in products marketed as legal food supplements raises questions about quality control and extraction standards.
Why does this happen?
Several factors contribute to the gap between label claims and actual content.
Extraction variability. The CBD content of hemp plants varies depending on the strain, growing conditions, and harvest timing. If a manufacturer does not rigorously test each batch of raw material, the starting concentration of CBD going into production is already uncertain.
Processing losses. CBD can degrade during extraction, purification, and formulation. If the manufacturer's process is not tightly controlled, some CBD may be lost between the raw extract and the finished product, resulting in a lower concentration than intended.
Inadequate testing. Not all brands test their finished products. Some test the raw extract but not the final oil after it has been diluted in a carrier. Some use in-house testing rather than independent third-party laboratories. Some simply label based on the theoretical concentration they intended to achieve rather than what they actually measured.
Deliberate mislabelling. It would be naive to exclude this possibility. In a market where regulation is still catching up and enforcement is limited, the financial incentive to overstate CBD content is obvious. A higher stated concentration justifies a higher price.
How to protect yourself
The existence of mislabelled products does not mean all CBD products are unreliable. It means you need to apply some basic due diligence. The tools for doing this are available to anyone.
Check the Certificate of Analysis. A CoA from an independent, UKAS-accredited laboratory is the single most reliable indicator of product quality. The CoA should be batch-specific (matching the lot number on your product), recently dated, and issued by a named laboratory you can verify independently. If the CoA shows CBD content within 10% of the label claim, that is generally considered acceptable.
Look for the FSA public list. Products on the FSA's Novel Food public list have at least met the threshold of having a validated application in progress. This does not guarantee product quality, but it indicates a minimum level of regulatory engagement.
Be sceptical of extraordinary claims. If a product claims an unusually high CBD concentration at an unusually low price, the arithmetic may not hold up. Calculate the cost per milligram and compare it against the market range. Significant outliers deserve scrutiny.
Check the extraction method. CO2 extraction generally produces cleaner products with fewer residual solvents than solvent-based extraction. This is not absolute — a well-run solvent extraction can be clean, and a poorly run CO2 extraction can have issues — but as a general indicator, CO2 is the safer bet.
What needs to change
The UK CBD market has a quality problem that self-regulation has not solved. The FSA's Novel Food process is slowly bringing the industry into compliance, but full authorisations are still pending and enforcement of products not on the public list has been inconsistent.
Consumers are currently bearing the burden of quality assurance that should be handled by effective regulation. Until that regulation catches up, the practical advice remains the same: check the lab reports, verify the claims, and do not assume that a professional-looking label means a professionally manufactured product.
The honest summary
Independent analysis shows that a significant proportion of UK CBD products do not contain the amount of CBD stated on their labels. Some contain residual solvents or heavy metals. These findings are not from activist groups or competitors — they are from peer-reviewed scientific studies published in reputable journals.
This does not mean CBD products are inherently dangerous. It means the market has quality control issues that consumers need to be aware of. The solution is not to avoid CBD, but to be informed about what you are buying and to demand transparency from the brands you choose to trust.
Check the lab reports. They exist for a reason.