Does Fish Oil Lower Cholesterol? Here's What the Research Actually Says

You've been told your cholesterol is creeping up. Your GP suggests eating better, exercising more — and maybe trying fish oil. Omega 3 has a solid reputation for being heart-healthy, so it seems like a logical step. But does fish oil actually lower cholesterol? Or is this one of those cases where the supplement world has run ahead of the science?

The honest answer: it depends on which number you're talking about, and most articles conveniently skip over that distinction. Fish oil doesn't work quite the way most people assume — and understanding why is worth a few minutes of your time, especially if you're looking to support your heart health properly.

Cholesterol and Triglycerides: Not the Same Thing

Before getting into what fish oil does or doesn't do, it helps to separate two things that often get lumped together: cholesterol and triglycerides. They're both fats in your blood, and both matter for heart health, but they behave differently and respond to different interventions.

Cholesterol — specifically LDL ("bad") and HDL ("good") — is what most people think of when they hear the word. Triglycerides are a separate type of blood fat, often elevated in people who eat a lot of refined carbohydrates, drink regularly, or have metabolic issues. High triglycerides are a risk factor for cardiovascular disease in their own right.

Why does this matter? Because fish oil is extremely good at one of these and only moderately useful for the other. And most of the marketing conflates the two.

What Fish Oil Actually Does Well: Triglycerides

Here's where fish oil genuinely earns its reputation. The evidence on omega 3 fatty acids — specifically EPA and DHA, the two active forms found in fish oil — and triglycerides is robust. Studies suggest omega 3s may reduce serum triglyceride levels by around 15–30%, depending on dose and baseline levels. The American Heart Association has endorsed prescription-strength omega 3 for treating high triglycerides in people at cardiovascular risk.

The mechanism is reasonably well understood: EPA and DHA appear to reduce the liver's production of triglyceride-rich particles and increase the rate at which those fats are cleared from the blood. If your triglycerides are elevated, there's a genuine case for fish oil.

This matters more than many people realise. Persistently high triglycerides are associated with atherosclerosis — the build-up of plaques in artery walls — and, in severe cases, with pancreatitis. Getting them under control is a legitimate goal, and fish oil may support that process meaningfully alongside dietary changes.

The Complicated Truth About Fish Oil and Cholesterol

Here's where it gets more nuanced. Fish oil is not consistently proven to lower LDL cholesterol — and in some circumstances, particularly at higher doses, it may actually nudge it upward.

Across multiple studies, DHA (one of the two main omega 3s in fish oil) has been shown to modestly increase LDL levels in some populations. EPA, on the other hand, appears to have a more neutral effect on LDL. This distinction — EPA versus DHA — matters more than most supplement labels let on, because the majority of fish oil products contain a blend of both.

The picture isn't all bad, though. When DHA does increase LDL, it also tends to increase LDL particle size. Larger, fluffier LDL particles are considered less harmful than small, dense ones — so the number going up doesn't necessarily mean your cardiovascular risk increases in the same proportion. Omega 3s also fairly reliably raise HDL (the "good" cholesterol), particularly the most cardioprotective form, HDL2. And fish oil consistently reduces non-HDL cholesterol — a broader measure of all harmful cholesterol-carrying particles — which many cardiologists consider a more useful marker of risk than LDL alone.

So when someone asks "does fish oil lower cholesterol?", the most accurate answer is: it has a mixed but broadly positive effect on your overall lipid profile, with the strongest evidence sitting firmly in the triglyceride column rather than the LDL column. That's not nothing — it's actually quite significant — but it's different from the clean "yes, it lowers cholesterol" story that often gets promoted.

Does Dose Matter?

It does, quite a bit. Most of the strongest evidence around triglyceride reduction comes from studies using 2–4 grams of EPA and DHA per day. Many standard over-the-counter fish oil capsules provide around 300mg of combined EPA and DHA per 1,000mg capsule — meaning you'd need seven to ten capsules a day to reach the doses used in clinical trials.

This is one of the most overlooked problems with fish oil supplementation: the gap between what's been studied and what people actually take. A low-potency capsule taken once a day is unlikely to produce the lipid effects that a properly dosed intervention does. If you're taking fish oil for cardiovascular support, the potency of the product matters as much as the habit of taking it.

High-strength fish oil supplements — those providing 500mg or more of EPA and DHA per capsule — get you to a useful dose far more efficiently. It's also worth checking whether the product lists separate EPA and DHA values rather than just total "omega 3 content," since the blend matters when it comes to how the supplement affects your lipid profile.

What Else Omega 3 Does for Heart Health

Even setting aside the cholesterol debate, there are solid reasons to care about your omega 3 intake.

Fish oil may modestly reduce blood pressure in people with elevated readings. It has anti-inflammatory properties that are directly relevant given the role chronic inflammation plays in cardiovascular disease. EPA in particular appears to help stabilise heart cell membranes, which may reduce the risk of arrhythmia. And there's a meaningful body of evidence linking regular oily fish consumption — two portions a week, ideally — with lower rates of cardiovascular mortality.

Beyond the heart, omega 3s are associated with improved brain function, reduced joint stiffness, and better mood — particularly relevant in the 40s-plus bracket, where these things tend to become more noticeable. The body can't make EPA and DHA on its own. You're either getting them from food or from supplementation. Most people in the UK consistently fall short of the recommended intake.

Fish oil works best as part of a broader approach — a diet lower in saturated fat and refined carbohydrates, regular movement, and addressing any underlying metabolic issues. But as a daily habit that costs relatively little effort, the cumulative benefit across multiple cardiovascular risk factors is worth taking seriously.

How Good Fats Supports Your Omega 3 Intake

If you're thinking about adding a quality fish oil to your routine, the potency of what you're taking is the thing most worth getting right.

Good Fats from Lean Greens provides 500mg EPA and 250mg DHA per capsule — 750mg of combined omega 3 per softgel, which is three to four times the concentration of many supermarket fish oils. That gap matters if you're taking fish oil for a reason rather than as a vague precaution.

It's UK-manufactured, comes without the fishy aftertaste that puts so many people off omega 3 supplements, and is straightforward to work into a daily routine. You can take one to three capsules a day depending on what you're after — making it easy to build toward a more effective intake without swallowing a handful of capsules.

[Good Fats product page]

Fish oil won't rewrite your cholesterol numbers overnight, and it's not a substitute for medical advice if you're managing a diagnosed condition — always check with your GP if you're on medication or have been told your lipids need active management. But if you want to support your triglyceride levels, nudge your overall lipid profile in the right direction, and give your heart a bit more of what it actually needs day-to-day, a high-potency omega 3 is one of the more sensible daily habits you can build. If that sounds like a useful addition, Good Fats is a solid place to start.