How to Read Omega-3 Supplement Labels for EPA and DHA

Start with the serving size

A fish oil bottle may show 1,000 milligrams in large type on the front. Before comparing it with another bottle, turn it around and look at Supplement Facts. The front number may describe the weight of the oil, which contains other fats in addition to the omega-3s you are trying to compare. The amounts of EPA and DHA, when listed, give you a more specific comparison.

Start at the top of the panel. Some products list one softgel as a serving, while others list two or more. Liquid products may use a measured volume. The quantities on the panel usually describe a serving, so note that serving size alongside the milligrams. This step can explain why two bottles that look similar at first appear to contain different amounts.

EPA and DHA stand for eicosapentaenoic acid and docosahexaenoic acid. NIH identifies them as two of the main omega-3 fatty acids. If the label lists them separately, add their amounts to find the combined EPA and DHA per serving. Keep the individual numbers, too, if you want to compare products with different proportions.

For a related guide, read How to Read Iodine Supplement Labels: Kelp and Iodide.

Compare like with like

Imagine a label that lists 180 milligrams of EPA and 120 milligrams of DHA in one softgel. Together, that is 300 milligrams of EPA and DHA. Another label lists 360 milligrams of EPA and 240 milligrams of DHA in a two-softgel serving. That is 600 milligrams per serving, or 300 per softgel. These examples show how to read the label. They are examples of arithmetic rather than amounts to take.

Some panels list fish oil, total omega-3s, EPA and DHA on separate lines. Those numbers can overlap because EPA and DHA can be part of the total omega-3s, which in turn can be part of the oil. Adding all the lines together would count some of the same material twice. If the label gives only a total and you want the individual amounts, check whether the manufacturer provides a complete panel or ask a pharmacist for help comparing it.

For a related guide, read Vitamin K1 vs. K2: How to Read Supplement Labels.

Check where the omega-3s come from

NIH lists fish oil, krill oil, cod liver oil and algal oil among the sources used in supplements. Algal oil is an option for people looking for an alternative to fish-derived oil. Look at the EPA and DHA lines on each bottle, because the source name alone does not tell you how much of either it contains. If you avoid animal ingredients, check the capsule ingredients as well as the oil.

Flaxseed oil supplies primarily ALA, another omega-3 fat. The body can convert some ALA to EPA and DHA, but NIH notes that the conversion is limited. Use the ingredient name on the label to see what is actually in the product. Cod liver oil can also provide vitamins A and D, so check those lines if you already take a multivitamin or another product with either vitamin.

Bring the label to the conversation

A side-by-side comparison can help you see what each bottle contains. Whether a supplement fits your needs depends on why you are considering it, what you already eat and any medicines or supplements you take. Over-the-counter omega-3 supplements and prescription omega-3 medicines serve different purposes. If a clinician has recommended a prescription product, ask before making any change.

Take a photo of the front and the full Supplement Facts panel if you want to discuss a product with a pharmacist or clinician. Include the serving size, both fatty acid amounts and any added vitamins. Mention medicines such as warfarin, since omega-3 supplements can interact with medications. If you are comparing several products, bringing the labels lets the conversation start with their actual ingredients instead of the largest number printed on the bottle.