What is it used for?
Source of essential fatty acids for the maintenance of good health [Source note 2].
Source of omega-6 fatty acids for the maintenance of good health [Source note 3].
Source of linoleic acid (LA) for the maintenance of good health [Source note 4].
Note: The above uses can be combined on the product label (e.g., Source of omega-6 fatty acids, including linoleic acid, for the maintenance of good health).
What this guide covers
The solidus (/) indicates that either term or statement may be selected by the applicant.
Who does this guide cover?
Adults 18 years and older
How is it taken?
Oral
Which forms are covered?
this reference excludes foods or food-like dosage forms as indicated in the Compendium of references Guidance Document.
Although delayed release dosage forms are usually not supported by source authority's references, this reference includes ‘Capsule, soft, enteric-coated’ which may be used for products containing fixed oils.
Quantities
Method of preparation: Non-standardized fixed oil
1.3-6 grams of evening primrose oil, per day [Source note 5].
Method of preparation: Standardized fixed oil
1.3-6 grams of evening primrose oil, per day [Source note 6] standardized to:
7-14% gamma-linolenic/gamolenic acid (GLA), and/or
65-85% linoleic acid (LA).
Note: The following potency information is considered as additional information and can be included on the label: XX% total omega-6 fatty acids
How is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
How long is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Warnings and precautions
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
When should it be avoided?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Possible side effects
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Storage
Must be established in accordance with the requirements described in the applicable product regulations.
All products (information for industry; not for labelling)
To be packaged in airtight container, protected from light [Source note 7].
Preparation details
Ingredient identity, preparation requirements, and other details that define the scope of this guide.
Ingredients and preparations
| Proper name(s) | Common name(s) | Source information / Source material(s) | Source information / Part(s) |
|---|---|---|---|
| Oenothera biennis |
| Oenothera biennis | Seed |
References: Proper name: 2024; Common names: Brayfield and Cadart 2007, Gardner and McGuffin 2013; Source information: Brayfield and Cadart 2007, WHO 2002.
Other ingredients
Must be chosen from the current source ingredient database and must meet the limitations outlined in the database.
Preparation and quality requirements
The finished product specifications must be established in accordance with the requirements described in the source authority source’s product quality guidance.
The active ingredient must comply with the requirements outlined in the source ingredient database.
Guide change history
Updates to this SupplementSafety.org guide.
Minor updates
Updated guide wording, organization, and source presentation. Added our editorial change history.
Initial release
Initial SupplementSafety.org guide prepared from source reference material.
Validation: Not yet completed. Editorial updates do not constitute clinical validation.
Sources
Source information
This guide organizes source material about uses, preparations, amounts, and precautions. Read the conditions alongside each statement; the information may apply only to particular preparations or populations.
The source document includes supporting references. We have not independently summarized or assessed every cited study for this guide.
- Source document version
- February 27, 2026
- Source captured
- Aug 15, 2026
- Editorial work
- Editorial preparation. Independent clinical review has not been recorded for this guide.
Full citations are available through the link above. Verification is required to open them; reading this guide does not require verification.
Taking a medication too?
Explore our supplement–medication interaction checker. Its coverage and review status are shown with the results; a missing finding does not establish that a combination is safe.