Pick up any bottle of fish oil and the biggest number on the front is usually 1000mg. It looks like the answer to the question you care about, which is how much omega-3 you are getting. It is not. That number is the weight of the oil in each capsule, and the omega-3 figure is in smaller print on the back.
This guide walks through six things to check on a fish oil label, in the order you will find them on the bottle, so you can compare products on what is actually inside rather than on the size of the number on the front.
Short version: Ignore the big number, find the EPA and DHA lines, and multiply by the capsules you will take each day. Then check purity, source and precautions. You can see a full label on our CtoMi Fish Oil 1000mg page.
Who this guide is for
- You are standing in front of a shelf of fish oil and every bottle says 1000mg
- You already take fish oil and are not sure how much EPA and DHA you get from it
- You want to compare two products fairly, not by bottle size alone
- You are deciding between fish oil and a plant-based omega-3 such as flaxseed oil
Check 1: the big number is the oil, not the omega-3
The 1000mg on the front tells you how much fish oil is in one capsule. Fish oil is a mix of different fats, and only part of it is the omega-3 fatty acids most people are buying it for. Two bottles can both say 1000mg and deliver quite different amounts of omega-3.
So treat the front of the bottle as the capsule size. The useful information starts on the ingredients panel.
Check 2: find the EPA and DHA lines
EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the two omega-3 fatty acids that fish oil is known for. A clear label lists each one separately, in milligrams per capsule.
Look for a line that reads something like "Fish Oil 1000mg, equiv. EPA 180mg, equiv. DHA 120mg". Add the two together and you have the combined EPA and DHA per capsule, which is the fairest single number for comparing products. If a label only gives a total for "omega-3" or "marine lipids" without breaking out EPA and DHA, you have less to compare with.
Check 3: do the per-day maths
Labels state amounts per capsule, but what matters is what you take in a day. Find the directions, then multiply.
Here is how that works for a capsule with 180mg of EPA and 120mg of DHA, taken at the one to two capsules a day that many fish oil labels suggest:
| Capsules a day | Fish oil | EPA | DHA | EPA and DHA combined |
|---|---|---|---|---|
| 1 | 1000mg | 180mg | 120mg | 300mg |
| 2 | 2000mg | 360mg | 240mg | 600mg |
Run the same sum for any product you are comparing. While you are there, divide the capsule count by your daily capsules to see how long the bottle will last. A 180 capsule bottle lasts about six months at one a day and about three months at two.
How much EPA and DHA is right for you depends on your diet and your health, so if you are aiming for a specific daily amount, ask your GP or pharmacist.
Check 4: purity and freshness
Fish oil comes from the sea, so it is reasonable to ask what else came with it. Look for a plain statement about purification and heavy metals, such as mercury testing, and about oxidation, which is the label word for how fresh the oil is.
Oxidation can affect fish oil quality and may contribute to unpleasant odours or flavours. However, smell alone is not a reliable measure of freshness. Look for products with documented quality testing, including oxidation and contaminant testing where available.
Check 5: where the omega-3 comes from
Not every omega-3 supplement is fish oil, and the source changes which omega-3 you get.
- Fish oil comes from the tissue of oily, cold-water fish and supplies EPA and DHA directly.
- Flaxseed oil is plant-based and supplies a different omega-3 called ALA (alpha-linolenic acid). Your body can convert some ALA into EPA and DHA, but only a limited amount, so the two are not interchangeable on a label.
If you do not eat fish, or you want a plant-based option, Flaxseed Oil 1,000 lists 500mg of ALA per capsule alongside omega-6 and omega-9. Compare ALA with ALA and EPA and DHA with EPA and DHA, not one against the other.
Check 6: read the precautions panel
The small print is part of the label too. Before you buy, check for:
- Allergy warnings. Fish oil is not recommended for anyone with a seafood allergy.
- Pregnancy and breastfeeding. Labels will usually ask you to consult your healthcare professional first.
- Prescription medication. If you take any, including blood thinning medication, talk to your GP or pharmacist before adding fish oil.
- Directions. Stay within the daily capsules stated on the label unless a health professional has advised otherwise.
Worked example: reading the CtoMi label
Here is the same six-step check run on our own fish oil capsules, so you can see what a complete label looks like.
- Capsule size: Fish Oil 1000mg per capsule.
- EPA and DHA: 180mg of EPA and 120mg of DHA per capsule, listed separately.
- Per day: the directions are 1 to 2 capsules daily or as professionally directed, which works out to 300mg to 600mg of combined EPA and DHA. The bottle holds 180 capsules.
- Purity and freshness: the oil goes through a purification process to meet global oxidation level standards and to be free from mercury and other heavy metals.
- Source: the oily tissue of cold-water fish.
- Precautions: not recommended for anyone with seafood allergies. If pregnant, lactating or taking prescription medication, consult your healthcare professional.
EPA and DHA are important omega-3 fatty acids involved in normal cell function. DHA is a structural component of the brain and retina, while EPA and DHA have been widely studied for their roles in cardiovascular health. Always read the label and take only as directed.
Fish oil sits alongside our other everyday options in the heart, brain and healthy ageing range.
Your fish oil label checklist
Save this for the next time you compare bottles:
- How many milligrams of EPA per capsule?
- How many milligrams of DHA per capsule?
- How many capsules a day do the directions say, and what is the daily EPA and DHA total?
- How many days will the bottle last at that dose?
- Does the label mention purification, heavy metals and oxidation?
- Is the source fish oil or a plant oil, and which omega-3 does it list?
- Do any of the precautions apply to you?
Frequently asked questions
Is fish oil the same as omega-3?
Not quite. Omega-3 is a family of fatty acids, and fish oil is one source of them. Fish oil supplies the omega-3s EPA and DHA, while plant oils such as flaxseed supply ALA. A 1000mg fish oil capsule contains less than 1000mg of omega-3, which is why the EPA and DHA lines matter.
What does 1000mg mean on a fish oil bottle?
It is the amount of fish oil in each capsule. The omega-3 content is listed separately as EPA and DHA. In our capsule that is 180mg of EPA and 120mg of DHA.
How many fish oil capsules should I take a day?
Follow the directions on your label. For CtoMi Fish Oil 1000mg that is 1 to 2 capsules daily, or as professionally directed. If you are taking fish oil for a specific health reason, your GP or pharmacist can advise on the amount that suits you.
Can I take fish oil and flaxseed oil together?
They supply different omega-3s, so some people take both. If you take prescription medication or already take several oil-based supplements, check with your GP or pharmacist first so the totals make sense for you.
Does fish oil go with other daily supplements?
It fits into most routines and is usually taken with a meal. We cover one common pairing in our guide to taking milk thistle and fish oil together.
The bottom line
A fish oil label is easy to read once you know where to look. Skip the big number, find the EPA and DHA, do the per-day maths, then check purity, source and precautions. If you would like a label that shows all six clearly, CtoMi Fish Oil 1000mg comes in a 180 capsule bottle. Shop it online in NZ.
