How does ALA differ from DHA and EPA?
5 min read
ALA, DHA and EPA are all omega-3 fatty acids, but they are different substances. DHA+EPA is the combined amount of two of them. ALA does not count towards that total.[1][2]
This distinction matters when comparing labels or prices. A declaration of 600 mg ALA does not establish 600 mg DHA+EPA. “Omega-3” on the front of a pack does not identify which fatty acids you are buying.
What is ALA?
ALA stands for alpha-linolenic acid. Sources of this omega-3 fatty acid include flaxseed oil, rapeseed oil and walnuts.[1]
DHA stands for docosahexaenoic acid and EPA for eicosapentaenoic acid. Their molecules have different structures from ALA, as their scientific notation shows:[2][3]
| Fatty acid | Notation | Carbon atoms | Double bonds |
|---|---|---|---|
| DHA | 22:6n-3 | 22 | 6 |
| EPA | 20:5n-3 | 20 | 5 |
| ALA | 18:3n-3 | 18 | 3 |
The notation describes the fatty acid’s structure. It is neither an amount per capsule nor advice about how much to take.
Also distinguish alpha-linolenic acid from linoleic acid. Their names look similar, but linoleic acid is an omega-6 fatty acid.[1]
Does plant-based omega-3 always mean ALA?
No. Flaxseed oil is a source of ALA, while algal oil in supplements can supply DHA and, depending on the product, EPA too.[1][2]
“Plant-based” or “vegan” alone therefore does not identify the omega-3 fatty acid in a product. Check the declared composition to establish that.
The oil source and the full ingredients list also answer different questions. Algal oil can be the oil source while the capsule shell contains other ingredients. Read more about oil sources in Fish oil or algal oil: what is the difference?.
Can the body convert ALA into DHA and EPA?
Yes. The body can form other omega-3 fatty acids from ALA, including DHA and EPA.[2] That conversion is a separate question from a supplement’s composition.
A label declaring 600 mg ALA describes how much ALA the product supplies on the stated basis. It does not declare how much DHA or EPA will later form in someone’s body.
When comparing packs, do not use an assumed conversion percentage to turn ALA into DHA+EPA. That would present an assumption about bodily conversion as the product’s contents.
How can you tell the difference on a label?
Look for the individual names and check whether amounts are given per capsule, per millilitre or per stated serving. Figures need the same basis before you compare them directly.
This fictional example refers to one capsule for both products. All figures are invented; they are not test results.
| Label declaration per capsule | Product A | Product B |
|---|---|---|
| Total omega-3 | 600 mg | 600 mg |
| DHA | Not listed | 400 mg |
| EPA | Not listed | 200 mg |
| ALA | 600 mg | Not listed |
Both labels declare 600 mg omega-3, but describe different fatty acids. For product B, the individual declarations allow you to calculate 400 + 200 = 600 mg DHA+EPA. Product A declares 600 mg ALA.
“Not listed” in this table does not mean 0 mg. Declared figures may be rounded, and a label is not a complete analysis. Do not use subtraction to record a missing DHA, EPA or ALA declaration as an exact zero.
An explicit DHA+EPA total can also be useful when the individual split is missing. Read more in What are DHA and EPA, and how do they differ?.
Can you compare prices per gram of omega-3?
Only if you make clear which fatty acid or combined amount you are using. “Price per gram of omega-3” is insufficiently precise without that explanation.
A price per gram of ALA and a price per gram of DHA+EPA use different fatty acids as their basis. A single price order mixing the two hides the difference in composition.
For a price per gram of DHA+EPA, compare the pack price with the amount of DHA+EPA in that pack. Do not add ALA to the denominator. If the available information does not establish the required DHA+EPA total, that price calculation remains unknown.
This is not a verdict on an ALA product. It means its ALA content does not put it on the same basis as products in a DHA+EPA price comparison.
What information do you need to compare further?
Check these details for each product:
- Which fatty acids are declared: DHA, EPA, ALA or only a total omega-3 amount.
- How much product the figures refer to: for example, one capsule or 5 ml.
- What the pack contains: the number of capsules or volume of liquid.
- Where the information comes from: the label for the correct pack and any additional sources.
A label declaration remains a manufacturer’s statement. A measured amount requires a relevant laboratory report; neither the word “omega-3” nor the oil source establishes that measurement.
On SUPPFAX, the price comparison uses DHA+EPA amounts declared on labels. Products containing only ALA belong outside that comparison. Missing information stays visible without becoming a negative judgement about quality.
Sources
Consulted on 31 October 2026.
- Voedingscentrum — Omega 3 en omega 6 (Dutch). For Dutch terminology, examples of ALA sources and the distinction from linoleic acid. ↩ ↩ ↩ ↩
- NIH Office of Dietary Supplements — Omega-3 Fatty Acids, Health Professional Fact Sheet. For the omega-3 family, ALA conversion and the presence of DHA and sometimes EPA in algal oil supplements. Stated source update: 22 August 2025. ↩ ↩ ↩ ↩
- EMBL-EBI ChEBI — DHA, CHEBI:28125, EPA, CHEBI:28364 and ALA, CHEBI:27432. Primary database records for molecular structure. ↩
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