VITAMINS & SUPPLEMENTS · GUIDE
A Fish Oil Label Checklist: What to Check Before Buying (No Brand Rankings)
A neutral checklist for reading a fish oil label, based on what labels must list and what lab studies found, with no brand names, rankings or personal amounts.
Content last updated . This page has not been medically reviewed.
Back to Omega Fatty AcidsWhat this page is
"How to choose fish oil" has no single answer, and this page does not rank or recommend any product. It is a checklist of things worth reading on a label, each tied to a source. Whether a supplement makes sense for you, and how much, is a question for a clinician or pharmacist, who can take your medicines and health conditions into account. If you are looking for the evidence on benefits, see Omega-3 evidence by use.The checklist
| Check | Why, and what the sources say |
|---|---|
| A US Supplement Facts panel must list the names and quantities of the dietary ingredients. [1] "Fish oil" weight is not the omega-3 amount. See EPA and DHA per serving vs fish oil total. |
| One serving equals the maximum amount the label recommends per eating occasion. [1] A serving may be several capsules. |
| In one US label review of 231 products, EPA plus DHA per serving ranged from 60.2 mg to 2,684 mg. [2] Do the arithmetic before comparing. |
| A supplement is not a prescription medicine. NCCIH notes that prescription omega-3 products differ in composition, testing and regulation, so their effects may not be the same. [3] See prescription omega-3 vs supplements. |
| Fish oil contains EPA and DHA, algal oil is a vegetarian source of DHA, some with EPA, and krill oil has omega-3 in phospholipid form. [3] Whether one form is better absorbed is a separate claim, covered on how to read a fish oil label. |
| Fish liver oil supplements are high in vitamin A, and the NHS advises avoiding them in pregnancy or when trying for a baby unless a GP advises otherwise. [4] See cod liver oil. |
| The NHS says allergies to fish or shellfish are quite common and can cause severe reactions. [4] Read the allergen line, and see fish and shellfish allergy and omega-3 products. |
| Oils oxidize. Studies measured this with peroxide and anisidine values, and in one New Zealand study 83 percent of products exceeded the recommended peroxide level. [5] A later study of 47 products reported much better compliance. [6] Results vary by market and method. |
| A claim on the front is not testing. See quality testing and certifications for what programs generally cover. |
| Be wary of "supports everything" wording. For one of the studies above, the 10 products all suggested benefits across heart, brain and joint health. [7] |
Things that are weak signals
One study of New Zealand products concluded that best-before date, cost, country of origin and exclusivity were all poor markers of supplement quality. [5] This is one study in one market, but it is a reason not to treat price, origin or a long date as proof of quality.What labels cannot tell you
- Whether the product will help you. Label claims and trial results are different things.
- Whether it is oxidized. The studies we read measured this in a laboratory.
- Whether it is right with your medicines. That is a conversation for a pharmacist.
- The US FDA says that supplement firms are responsible for evaluating the safety and labeling of their products before marketing. [8] The agency can act on adulterated or misbranded products after they reach the market. [8]
Frequently asked questions
Is there a best fish oil?
We do not rank products. The sources we read show that label accuracy and oxidation varied between studies and markets, so no single answer is supported. [5] [6]
What should I look at first on the label?
The EPA and DHA lines and the serving size. Fish oil weight alone does not tell you the omega-3 amount. [1]
Does a higher price mean better quality?
One New Zealand study found cost to be a poor marker of quality. [5]
Is a fish liver oil the same as fish oil?
No. Fish liver oil supplements are high in vitamin A, which the NHS says can be harmful to an unborn baby. [4]
Should I check with someone before buying?
Yes, if you take blood thinners, are pregnant, have a fish or shellfish allergy, or have heart rhythm, kidney or liver conditions. NCCIH advises talking with your health care providers about any complementary health approach you use. [3]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
Fish oil can interact with medicines that affect bleeding and may matter before surgery. An analysis of trials found a higher bleeding risk with prescription EPA ethyl ester specifically. [9] A pooled analysis of seven large trials found more atrial fibrillation with marine omega-3 supplements, with greater risk in trials using more than 1 g a day. [10] Side effects are usually mild, such as unpleasant taste, bad breath, heartburn, nausea and diarrhea. [3] Do not stop a prescribed medicine on your own. Tell your surgical team and pharmacist about supplements. See Omega-3 safety and interactions and questions to ask your clinician or pharmacist.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.