How to Read an Argan Oil Certificate of Analysis
A certificate of analysis is the supplier’s statement about one specific lot. Reading it well takes five minutes and catches most problems before oil reaches your tank.
- By
- ArganOil.us Sourcing Team
- Published
- Reading time
- 4 min
Key takeaways
- A COA reports measured results for one lot; the specification sets the limits it is judged against.
- Every result should name a test method — for vegetable oils these are commonly ISO 660, ISO 3960, ISO 3656 and ISO 12966-2.
- Check units: acidity as g/100 g oleic acid and acid value in mg KOH/g are different numbers.
- Results reported only as “conforms”, or a lot number that does not match the container, are reasons to hold the lot.
COA vs specification: two different documents
The specification is the agreed contract: parameters, limits and methods for a grade. The COA is the evidence that one lot met them. You need both, and they must use the same parameters and units — otherwise you are comparing numbers that do not line up. Our technical document pack pairs each grade’s specification with a representative COA; the reference ranges themselves are explained in argan oil specifications explained.
Read the header first
- Product name, grade and processing (virgin, deodorized, refined)
- INCI name and botanical source
- Lot or batch number — it must match the container label
- Manufacturing (pressing) date, analysis date and any retest or best-before date
- Laboratory name and whether it is in-house or independent
- Signature or electronic approval of the person releasing the lot
A COA dated long after pressing is not wrong in itself, but it tells you the oil has been stored; check the storage history — see argan oil storage and shelf life.
Then check each result against its method
| Parameter | What it indicates | Typical method |
|---|---|---|
| Free acidity / acid value | Hydrolysis of the oil — kernel quality and handling | ISO 660 |
| Peroxide value | Primary oxidation products (early rancidity) | ISO 3960 |
| K232 / K270 (UV absorbance) | Primary and secondary oxidation; K270 also rises with refining | ISO 3656 |
| p-Anisidine value | Secondary oxidation products | ISO 6885 |
| Fatty-acid composition | Identity and blending check | ISO 12966-2 (GC of FAMEs) |
| Tocopherols | Natural antioxidant content | ISO 9936 |
These ISO methods are the ones used in recent argan oil research,[2] and published supplier specifications sometimes cite European Pharmacopoeia methods instead.[3] Either is acceptable if the specification names the same method. What is not acceptable is a number without a method.
Watch the units
The Moroccan standard expresses acidity as g/100 g (percent oleic acid), with extra-virgin oil below 0.8.[1] Many specifications instead state acid value in mg KOH/g — one published argan specification sets a maximum of 4.0 mg KOH/g.[3] The two scales are not interchangeable, so confirm which one your limit uses before judging a result.
Use the literature as a plausibility check
For extra-virgin argan oil the literature cites peroxide value below 15 mEq O₂/kg and K270 at or below 0.25; the Moroccan standard does not set a K232 limit, though one study proposes 2.52.[1] Fatty-acid results well outside published ranges — for example linolenic acid above about 0.3 g/100 g — deserve a question before the lot is released.
Example COA, lot COA and your own incoming test
Suppliers typically share two kinds of COA. An example COA — from a recent, representative lot — supports qualification before you buy. A lot COA travels with each delivery and is the one your receiving team checks against the container label. Neither replaces your own incoming inspection; they tell you what to expect and where to look.
How much you retest depends on risk. Many cosmetic manufacturers confirm identity (fatty-acid profile) on the first lots from a new supplier, then move to reduced testing — acidity, peroxide value and odour — once a record of agreement between supplier COAs and in-house results exists. Keep a retained sample from each lot for the product’s shelf life so any complaint can be traced back.
If you are still evaluating, test a bulk-representative sample against the same methods the supplier uses; differences in method explain more COA disputes than differences in oil.
Red flags that justify a hold or retest
- Results written as “conforms” or “pass” with no numbers
- No test methods, or methods that differ from the specification
- Lot number or product name that does not match the container
- Analysis date before the pressing date, or no dates at all
- Identical results across different lots
- A fatty-acid profile that sits at the edge of, or outside, the published argan ranges
When a COA raises questions, test a retained sample in your own or a third-party lab against the same methods. Our quality control page explains how our lots are released and how discrepancies are handled.
Sources
Figures in this article come from the sources below, checked on September 30, 2026. Supplier listings are cited as evidence of market practice only.
- Argan Oil: Chemical Composition, Extraction Process, and Quality Control (Gharby & Charrouf, Frontiers in Nutrition, 2022) — Frontiers in Nutrition.
- Effects of physical refining process on quality and stability of argan oil (Asbbane et al., Scientific Reports, 2024) — Scientific Reports (Nature Portfolio).
- Product specification Sp213025c — Argan oil cold pressed toasted — Heess GmbH (published supplier specification).
Prepared by the ArganOil.us Sourcing Team. General information for B2B buyers — not legal, regulatory or customs advice. ArganOil.us terms (grades, formats, minimums, lead times) are confirmed with each quotation.