Written by Hannah Boyd
Naturopath, Herbalist, Nutritionist, BA, Adv Dip Nat, Nut, WHM.
Not All Fish Oils Are Equal: How to Choose One That Actually Works
Fish oil is one of the most commonly recommended supplements in clinic, and for good reason: it’s genuinely useful for joint health, inflammation, brain function, skin, and cardiovascular health.
But here’s what most people don’t realise when they’re standing in front of a pharmacy shelf: not all fish oils are created equal, and the difference between a good one and a mediocre one isn’t the price tag on the box. It’s what’s actually inside the capsule.
EPA vs DHA — What's the Difference?
Every fish oil label lists a total Omega-3 figure, but that number on its own doesn’t tell you much. What matters is the breakdown between EPA and DHA; the two active components doing different jobs in your body.
EPA is the one that does the heavy lifting for inflammation. DHA has a stronger affinity for brain function and cell repair. Most conditions we’re treating fish oil for (joint pain, general inflammation, cardiovascular support) depend on getting enough EPA specifically, not just a high total Omega-3 number.
How Much EPA Do You Actually Need?
This is where most off-the-shelf fish oils fall short. Clinical trials on fish oil for inflammation, including joint damage, show a therapeutic dose needs at least 2,000mg of EPA daily to be effective. That’s the number to work backwards from, not the total Omega-3 figure on the front of the box.
Most standard fish oil capsules contain around 1,000mg of Omega-3 total, but only about 340mg of that is EPA. To hit a therapeutic 2,000mg EPA dose, you’d need at least 6 capsules a day. Lower-quality brands often contain closer to 180mg EPA per capsule, meaning you’d need 11 capsules daily to get the same effect.
Read the EPA number specifically before you buy, not just the total Omega-3 figure on the front label.
Capsules vs Liquid — Which Is Easier to Get Right?
If 6+ capsules a day sounds unrealistic (fair), liquid fish oil is worth considering. It typically comes at a much higher concentration, so one teaspoon can deliver your full 2,000mg EPA dose in one go. Many people also find liquid causes less reflux than capsules, and it’s obviously a lot easier than swallowing half a dozen pills.
Quality liquid oils are flavoured and generally quite palatable, not the fish-burp experience people remember from decades ago.
What to Check on the Label Before You Buy
- EPA and DHA content specifically, not just total Omega-3
- Sourcing and processing — look for ethically sourced, cold-pressed oils
- Fish size — smaller fish (like anchovies and sardines) carry a lower risk of heavy metal accumulation, particularly mercury, compared to larger predatory fish
- Practitioner-only brands — these are generally held to higher testing and purity standards, and it’s usually worth paying a little more for this reason alone
Who Should Be Cautious With Fish Oil
Fish oil isn’t right for everyone at every dose, and it’s worth flagging before you start:
- If you’re on anti-platelet or anti-coagulant medication (such as warfarin or aspirin), fish oil can further thin the blood, increasing bleeding risk — this combination needs medical supervision, not a DIY approach
- If you have an upcoming surgical procedure, most practitioners recommend stopping high-dose fish oil in the lead-up, as it can affect clotting
- If you’re on other medications regularly, it’s worth checking for interactions before starting a high-dose regimen
None of this means fish oil is off the table if any of these apply to you, it means the dose and decision should be made with your naturopath or GP, not worked out alone from a supplement label.
If you’re not sure which fish oil is right for you, or want a dose worked out for your specific needs, book a consult OR browse our recommended practitioner-only range — we’re happy to help you cut through the label confusion.
