Kymata Health CBD Guide
How to read a CBD certificate of analysis
The lab report is the only way to know what is in the bottle. Here is what to check, in order.
Why the COA matters
A certificate of analysis (COA) is a lab report for one batch. It is the only way to know what is in the bottle: when JAMA tested 84 CBD products sold online, only about 31% were within 10% of the label.[1]
Accuracy has improved since then. In Leafreport’s independent oil tests most big brands landed within 10%, but not all: Charlotte’s Web’s 500 mg oil tested 12.4% over its label.[2]
The 7-point COA checklist
1. Batch match: the lot or batch number on the COA matches your bottle (or the QR code on the label opens that batch’s report).
2. A real, independent lab: the lab’s name and address are printed, and it is accredited to ISO/IEC 17025 (look for a PJLA, A2LA or similar accreditation number). A COA on the brand’s own template with no lab named is a warning sign.
3. Potency accuracy: total CBD within about 10% of the label. Compare like with like: mg per mL × bottle size = mg per bottle.
4. THC: for a THC-free product, total THC (delta-9 THC + 0.877 × THCA) should read ND. For full spectrum, multiply mg/mL by the bottle size to see the total per container.
5. Heavy metals: arsenic, cadmium, lead and mercury tested and below limits. Hemp pulls metals from soil; a study of 29 pet hemp products found heavy metals in 4.[3]
6. Pesticides and residual solvents: a multi-residue pesticide panel, and solvents such as butane, ethanol or hexane from extraction, all ND or below limits.
7. Microbials (and mycotoxins): E. coli, Salmonella, yeast and mold, and aflatoxins. Many brands only publish potency; that is the most common gap we see.
Check the date
A COA should be recent and for the batch you hold. A product page that shows a two-year-old COA does not tell you about today’s bottle; look for a batch lookup on the brand’s lab-results page.
See how brands compare on these checks: CBD brands ranked by lab data.
Sources
- Bonn-Miller MO et al. Labeling accuracy of cannabidiol extracts sold online. JAMA 2017
- Leafreport: CBD oil market report (independent tests by Canalysis Laboratories), updated Oct 16, 2022
- Wakshlag JJ et al. Cannabinoid, terpene and heavy metal analysis of 29 over-the-counter veterinary hemp supplements. Vet Med (Auckl) 2020