How much EPA and DHA is actually in fish oil?
A 1000mg fish oil capsule usually contains about 300mg of the part that does anything. The front of the tub counts the oil. The panel counts the omega-3. Here is the gap.
Short answer: about 300mg in a standard 1000mg capsule. Fish oil is not the active ingredient. EPA and DHA are, and a conventional capsule is roughly 18% EPA and 12% DHA, with the other 70% being other fats. The number on the front of the tub is the weight of the oil, not the dose of the thing you bought it for.
This is the clearest example in the whole supplement aisle of a label that is accurate and still misleading.
The two numbers
Pick up almost any fish oil and the front says 1000mg. Turn it over and the panel lists EPA and DHA separately, usually 180mg EPA and 120mg DHA.
That ratio, 18 and 12, is the industry standard for unconcentrated fish oil. Both numbers are true. The 1000mg is the capsule's oil content. The 300mg is how much of it is omega-3.
Nobody is lying. They are just counting a different thing from the one you care about.
Why it matters for the dose
Research on EPA and DHA has generally used 2g to 4g combined per day, and the trials at the higher end are the ones people are usually thinking of when they buy fish oil.
At 300mg a capsule, 2g means around seven capsules a day. Nobody takes seven. Most people take one, sometimes two, which puts them at a tenth to a fifth of the studied amount.
That gap explains a lot of the disappointment. The supplement was not tested and found wanting. It was taken at a dose nothing was ever tested at.
Concentrated oils are the actual answer
Concentrated fish oils exist and they are not exotic. They carry 500mg to 800mg of combined EPA and DHA per capsule, sometimes more, because the oil has been processed to remove the fats that are not omega-3.
They cost more per capsule and usually less per gram of EPA and DHA, which is the only comparison that means anything. Two concentrated capsules can do what seven standard ones would.
Reading the panel
Three lines matter, and one of them is often missing.
EPA and DHA should each have their own milligram figure. If the label gives you only a combined "omega-3" number, that number may include ALA, which is a different fatty acid your body converts to EPA poorly.
Total omega-3 on its own is the weakest way to present this, and it is common.
What to do
- Add EPA and DHA, ignore everything else on the front. That sum is your actual dose.
- Price per gram of EPA plus DHA, not per capsule. Concentrated oils usually win, and the cheap tub usually loses once you divide.
- Count what you actually take. One capsule a day of a standard oil is roughly 300mg, which is a long way from the amounts used in research.
Related reading: do collagen supplements work and can you take too many supplements.
Verdict reads the label, not the reputation. Photograph the supplement facts panel and it pulls every dose, compares each against the amounts used in published research, and adds up your whole stack. It reports the arithmetic. It does not tell you what to take.
