Reading a certificate of analysis on a dog CBD product

What does a certificate of analysis tell you about CBD oil?

A certificate of analysis shows the actual chemical composition of a CBD product as measured by an independent laboratory. The document reports cannabinoid levels, THC content, and the presence or absence of contaminants including heavy metals, pesticides, residual solvents, and microbial contamination.

The COA verifies whether the product matches its label. A 2020 study published in Natural Product Communications tested 29 veterinary hemp supplements and found that only 10 of 27 products with sufficient CBD for analysis (37%) fell within 10% of their label claims. Four of the 29 products contained detectable heavy metal contamination, including lead in three products.

A 2024 study in Frontiers in Pharmacology analyzed 202 CBD products and found that 74% deviated from label claims by at least 10%, and heavy metals appeared in 44 products.

How do you read a CBD certificate of analysis?

Start with the batch or lot number. The COA must show the same batch or lot number printed on your product. A generic COA or one from a different production run does not verify the contents of the bottle you are holding.

Next, check the laboratory name and accreditation status. Legitimate testing comes from laboratories accredited under ISO/IEC 17025, the international standard for testing and calibration laboratories. The COA should state the lab's accreditation and include contact information.

The cannabinoid profile section lists CBD content, THC content, and often minor cannabinoids such as CBG, CBN, and CBC. According to the 2026 systematic review, industry practice considers a product accurately labeled when the measured CBD level falls within 10% of the label claim. THC must remain below 0.3% to meet federal hemp regulations and to reduce toxicity risk, as THC is toxic to both dogs and cats.

The contaminant testing section reports results for heavy metals, pesticides, residual solvents, and microbial contaminants. Each category should show "pass" or "ND" (not detected) for harmful substances, or list specific detected levels with a notation that they fall below regulatory limits.

Talk to your vet before choosing a CBD product for your pet, and use the COA to confirm what you are giving matches what the manufacturer claims.

Why does ISO/IEC 17025 accreditation matter?

ISO/IEC 17025 is the international standard for laboratories performing testing and calibration. Accreditation under this standard means the laboratory has demonstrated technical competence, uses validated testing methods, maintains proper equipment calibration, and follows quality assurance protocols.

Accreditation requires regular external audits and proficiency testing. Laboratories must prove they can produce accurate, reliable results before they receive accreditation, and they must maintain those standards to keep it.

For cannabis and hemp testing, ISO/IEC 17025 accreditation provides assurance that the testing methods can measure cannabinoid levels and detect contaminants at the necessary sensitivity levels. Without accreditation, there is no external verification of the laboratory's capabilities or the accuracy of its results.

How accurate are CBD product labels?

A systematic review published in 2026 examined 28 peer-reviewed analytical studies covering 937 CBD products. The review found that only 31.3% of products complied with the ±10% accuracy threshold commonly used to evaluate label claims.

The 2020 veterinary hemp supplement study found even lower accuracy rates. Of 27 products with sufficient CBD for analysis, only 37% were within 10% of their label claims. Some products contained significantly less CBD than stated, while others contained more.

Label inaccuracy creates two problems. Underlabeled products deliver less CBD than expected, which means dosing becomes guesswork. Overlabeled products may deliver more CBD than intended, which matters for animals where weight-based dosing requires precision. Check with your vet to determine the appropriate amount for your pet.

What contaminants show up in CBD products?

The 2020 veterinary hemp study detected heavy metals in 4 of 29 products. Lead appeared in 3 products, and other heavy metals including arsenic and cadmium were found in additional samples. Hemp plants absorb heavy metals from soil, a property called phytoextraction, so contamination often traces back to growing conditions.

The 2024 study found heavy metals in 44 of 202 CBD products tested. Pesticide residues and residual solvents from extraction processes also appear in some products, though the study found these contaminants less frequently than heavy metals.

Microbial contamination from mold, yeast, or bacteria can occur during processing or storage if proper manufacturing controls are not maintained. A complete COA tests for all of these contaminant categories.

What is the National Animal Supplement Council quality seal?

The National Animal Supplement Council (NASC) is a nonprofit industry organization that operates a quality certification program for animal supplements. Products bearing the NASC Quality Seal have undergone facility audits every two years, comply with labeling requirements, and are subject to random independent product testing.

The NASC program requires adverse event reporting, which means companies must track and report any negative reactions associated with their products. Membership requires adherence to good manufacturing practices and label accuracy standards.

The NASC seal indicates that a company has submitted to third-party oversight and agreed to ongoing quality monitoring. It does not replace the need for batch-specific COAs, but it provides an additional layer of verification that the manufacturer follows consistent quality control processes.

How often should COAs be updated?

Each production batch should have its own COA. Manufacturing processes, raw material sources, and environmental conditions can vary between batches, so testing one batch does not verify the next.

CBD products degrade over time. Cannabinoids break down with exposure to light, heat, and oxygen. A COA from the date of manufacture does not reflect the product's current state if months or years have passed. Some manufacturers provide stability testing data showing how cannabinoid levels change over the product's shelf life.

Batch-specific testing matters most. A company that tests once and uses the same COA for all subsequent batches is not providing meaningful quality verification. Look for COAs dated within the past few months and tied to the specific batch number on your product.

Does THC content in pet CBD matter?

THC is toxic to both dogs and cats. The compound affects the nervous system and can cause symptoms including lethargy, loss of coordination, vomiting, sensitivity to motion and sound, tremors, and changes in heart rate. In severe cases, THC toxicity requires veterinary treatment.

Federal hemp regulations require that hemp products contain no more than 0.3% THC by dry weight. A COA should confirm THC content stays below this threshold. Some products labeled as broad-spectrum or THC-free should show THC at non-detectable levels.

The 2020 veterinary hemp study found that some products contained more THC than their labels indicated. Accurate THC testing on the COA protects against accidental exposure, particularly for small dogs and cats where even low THC doses can cause toxicity. See your vet immediately if your pet shows signs of THC toxicity.

Where do you find a product's certificate of analysis?

Reputable manufacturers provide COAs on their websites, often in a dedicated quality or testing section. Some include a QR code on the product label that links directly to the batch-specific COA.

If a COA is not readily available, contact the manufacturer and request it. A company that cannot or will not provide a current, batch-specific COA from an accredited laboratory is not demonstrating basic quality assurance.

Before purchasing any CBD product for your dog or cat, confirm that the manufacturer routinely publishes COAs and that the available COAs include all essential testing categories: cannabinoid profile, heavy metals, pesticides, residual solvents, and microbial contaminants. If the documentation is incomplete or absent, choose a different product.

What does a missing or incomplete COA tell you?

A missing COA means you have no verification of what the product contains. Given that research shows the majority of CBD products fail to match their labels and that heavy metal contamination appears in a meaningful percentage of tested products, buying without a COA means accepting unknown risk.

An incomplete COA that tests only for cannabinoid content but omits contaminant testing leaves safety questions unanswered. Heavy metals, pesticides, and microbial contamination pose direct health risks that cannabinoid testing does not address.

A COA without a batch number, or one that does not match your product's batch number, provides no assurance about the specific bottle you purchased. Manufacturing variability means that one batch may meet quality standards while another does not.

If the COA comes from a laboratory without ISO/IEC 17025 accreditation, the results lack independent verification of accuracy. The testing may have been performed correctly, but without accreditation, there is no way to confirm the lab's competence or the reliability of its methods.