How to Read a Hemp COA (Certificate of Analysis) - With Real Examples

Written By Theo Kipnis

What a COA Tells You (and How to Find What You’re Looking For)

A lab results link on a hemp website leads to a page full of abbreviations, decimal points, and units of measurement that weren’t designed for a general audience. LOQ. ND. mg/g. HPLC. The information is all there - but without knowing which numbers to focus on or what the terms mean, it’s hard to turn that data into a confident buying decision.

A Certificate of Analysis - a COA - is one of the few tools available for evaluating a hemp product based on independent lab data rather than a brand’s description of itself. This guide walks through a hemp COA line by line, using ARC Farms’ actual lab results as examples, covering which numbers to check first, what the abbreviations mean, and what separates one product from another.

What Is a Certificate of Analysis?

A Certificate of Analysis is a lab report produced by a third-party testing facility. The hemp brand sends a sample of their product to an independent laboratory. The lab analyzes the sample and documents what it finds - the cannabinoid content, which tells you how much CBD, THC, and other compounds are present.

The key word is “third-party.” The brand doesn’t test its own product. An independent lab does. This separation removes the incentive to inflate numbers or selectively report results.

A brand that publishes COAs is providing data from an unbiased source about what’s in the product. A brand that doesn’t publish COAs is asking customers to take their word for it.

Most CBD Products Don’t Match Their Labels

Research analyzing commercially available CBD products found that only 38% tested within 10% of their labeled CBD content, with many products containing far less CBD than advertised (Liebling et al., 2022, Cannabis and Cannabinoid Research).

That means if a product label says “500mg CBD,” there’s roughly a 60% chance the actual content is significantly higher or lower than what’s advertised. These are products already on shelves with potency claims on the label - and the labels don’t match what’s inside.

A COA doesn’t guarantee perfect accuracy, but it provides a way to check. When a brand publishes lab results from an accredited independent lab, there’s data from an unbiased source about what the product contains. When a brand publishes only a number on a label, the customer is trusting that number without evidence.

ARC Farms publishes a Certificate of Analysis for every strain we sell. The numbers are good and we’d rather show you than tell you. View our lab results for Legendary OG, Daiquiri Factory, Strawberry Lemonade, or Payton’s Strawberries and follow along with this guide.

The Basics: What’s on Every COA

Not every lab formats a COA identically, but the core information is consistent.

Header Information

At the top of every COA: the lab’s name and accreditation, the date of testing, the sample ID or batch number, and the client’s name (the brand that submitted the sample). This tells you who tested it, when, and which specific batch the results apply to.

What to look for: a real lab name with contact information, a specific date, and a batch or lot number that connects the report to a specific product run.

Sample Description

This section identifies what was tested - the strain name, product type (flower, tincture, edible), and sometimes the weight of the sample submitted. It confirms that the report you’re reading is for the product you’re considering.

Cannabinoid Potency: Reading the Numbers

This is the section most people look at first - and the one with the most unfamiliar terminology. Here’s how to decode it.

The cannabinoids you’ll see listed:

  • CBD (cannabidiol) - the primary active compound in hemp flower. Listed as a percentage of dry weight. ARC Farms’ Legendary OG tests at 14.42% CBD - meaning each gram of flower contains approximately 144mg of CBD.

  • CBDa (cannabidiolic acid) - the raw, unheated form of CBD. Heat converts CBDa into CBD (this is why you smoke or vaporize flower). A high CBDa number on a flower COA is normal and expected - it means the CBD hasn’t been activated yet, which is correct for unprocessed flower.

  • Total CBD - this is CBDa multiplied by 0.877 (the conversion factor for decarboxylation) plus CBD. It represents the maximum CBD available if all the CBDa converts. This is the number to compare when looking across strains or brands.

  • Delta-9 THC - the compound that produces intoxication. For legal hemp, this must be below 0.3% by dry weight. ARC Farms’ Legendary OG tests at 0.18% Total THC - well within the legal limit and non-intoxicating.

  • THCa (tetrahydrocannabinolic acid) - the raw form of THC. This one deserves close attention, and we’ll cover it in detail below.

  • CBG (cannabigerol) and CBGa - minor cannabinoids that contribute to the full-spectrum profile. Lower concentrations than CBD but part of what makes full-spectrum different from isolate.

Understanding the units:

COAs typically report cannabinoid content in one of two ways: as a percentage of dry weight (%) or in milligrams per gram (mg/g). They’re the same number expressed differently - 14.42% CBD is the same as 144.2 mg/g.

High CBD, Low THC: What to Look For on a Hemp Flower COA

When evaluating a hemp flower COA, the cannabinoid numbers tell the reader two things at once: what the product will deliver and whether it’s what it claims to be.

CBD potency. Total CBD between 10% and 20% is the typical range from well-grown hemp flower. Below 8% may indicate older product or less developed genetics. Above 20% for total CBD on compliant hemp is unusual and worth looking at more closely.

THC compliance. Total THC (Delta-9 THC plus THCa converted) must be below 0.3% for the product to be legal hemp. ARC Farms’ strains range from 0.18% to 0.29% Total THC - all compliant and all non-intoxicating.

The CBD-to-THC ratio. On a hemp flower COA, CBD numbers should be dramatically higher than THC numbers. ARC Farms’ Legendary OG, for example, shows 14.42% CBD against 0.18% Total THC - roughly an 80:1 ratio. This is what a CBD-dominant hemp flower looks like on paper. That same ratio is also what separates CBD flower from THC flower as products on the shelf. CBD Flower vs THC Flower: The Real Differences Explained covers what each one feels like and how to shop safely for either. For more on how these ratios define different types of cannabis, read our guide to Type III cannabis explained.

Minor cannabinoids. CBG and CBGa in small quantities confirm a full-spectrum profile - the plant’s full range of compounds rather than a single isolated molecule. ARC Farms’ flower contains measurable CBG alongside the dominant CBD, which contributes to the entourage effect.

The THCa Loophole: The Most Important Line on a COA

This deserves its own section because it’s the single biggest issue in hemp flower right now - and a COA is the only way to spot it.

The 2018 Farm Bill made hemp legal as long as it contains less than 0.3% Delta-9 THC. But some brands have bred strains that are low in Delta-9 THC while being high in THCa - the precursor that converts to THC when you apply heat. A product can test at 0.2% Delta-9 THC (technically legal) while containing 15% or 20% THCa. The moment you smoke it, that THCa converts. What you’re smoking is, for all practical purposes, marijuana.

These products are marketed as “hemp” and sold in states where recreational marijuana remains illegal. The COA tells the real story.

On a COA, the two numbers to check are the Delta-9 THC percentage and the THCa percentage. If Delta-9 is below 0.3% but THCa is above 1%, the product is not what most people think of as CBD hemp flower. If THCa is in the double digits, the product will produce intoxicating effects.

ARC Farms’ flower has negligible THCa. Our Total THC (Delta-9 plus converted THCa) ranges from 0.18% to 0.29% across our four strains. That’s not a technicality. It reflects the genetics we chose to grow - strains bred for high CBD, not strains engineered to exploit a regulatory gap.

Red Flags on a COA

Not all COAs are created equal. Here’s what should give you pause:

No lab name or accreditation listed. A legitimate COA identifies the testing lab, their license or accreditation number, and contact information. If the testing lab can’t be identified, the document has no credibility.

No date or an old date. Lab results should be reasonably current. A COA without a date, or one from years ago, doesn’t tell you much about what’s in the product being sold today.

Suspiciously round numbers. Lab results carry decimal places because analytical instruments measure precisely. A COA reporting “15.0% CBD” exactly might raise fewer eyebrows than one reporting “14.42% CBD,” but the precise number is more credible.

No batch or lot number. Without a batch number, there’s no way to match the COA to a specific product. It might be from a different harvest, a different strain, or a different year entirely.

High THCa with low Delta-9 THC. As described above, this is the THCA loophole. If a product is sold as CBD hemp but the COA shows THCa above 1% - especially above 5% to 10% - the product will produce intoxicating effects when smoked.

The COA is an image, not a verifiable document. Some brands post screenshots or cropped images of COAs. A legitimate COA should be a full document - usually a PDF - with the lab’s letterhead, full results, and enough information to verify with the lab directly if you wanted to.

No COA at all. A brand that doesn’t publish lab results is asking customers to take their word for it. Given the research showing most CBD product labels don’t accurately reflect what’s inside, that’s a significant gap.

How ARC Farms Approaches Testing

ARC Farms sends flower to an independent, accredited laboratory for cannabinoid potency testing. The lab performs a full cannabinoid analysis - CBD, CBDa, THC, THCa, CBG, and Total THC compliance verification - and documents the results in a formal Certificate of Analysis.

We publish the full COA on each product’s page. Not a summary. Not selected numbers. The full lab document, available for independent review.

Each COA corresponds to a specific lot number. When a customer buys a jar of Legendary OG, the COA on the website corresponds to the product in the package. The COA shows what’s in the jar. Where and how the flower was grown is the other half of that picture - ARC Farms cultivates every strain in a climate-controlled greenhouse in Tucson under natural sunlight. More on ARC Farms’ greenhouse-grown hemp flower.

View the full COA pages for each strain:

Frequently Asked Questions

What is a certificate of analysis for CBD?

A Certificate of Analysis (COA) is a document produced by an independent laboratory that verifies what’s in a CBD product. It reports cannabinoid potency - how much CBD, THC, and other cannabinoids the product contains. It’s data from a third party, not a claim from the brand.

How do you read a hemp COA?

Start with the cannabinoid potency section. Look for Total CBD (your potency indicator) and Total THC (should be below 0.3% for legal hemp). Check the THCa number separately - high THCa on a “hemp” product means it will produce intoxicating effects when smoked. Then verify the basics: the lab is named and accredited, the date is current, and the batch number connects to a specific product. The guide above walks through each line in detail.

What should I look for on a CBD lab test?

Four things: (1) Total THC below 0.3% with low THCa, confirming it’s real CBD hemp and not a loophole product, (2) Total CBD that’s consistent with what the brand claims, (3) a named, accredited laboratory with a recent test date, and (4) a batch or lot number connecting the report to a specific product.

What does “below LOQ” mean on a COA?

LOQ stands for Limit of Quantification - the lowest concentration a lab’s instruments can reliably measure. “Below LOQ” or “< LOQ” means the substance is present in trace amounts too small to quantify precisely, or not present at all. On a cannabinoid potency report, this typically appears next to compounds that are at negligible levels.

Theo Kipnis
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