Omega-3 Dosage Guide: EPA vs DHA and How Much You Need

Omega-3 is one of the most popular supplements in Canada, and one of the easiest to get wrong. A bottle that says "1,000 mg fish oil" might give you far less of the omega-3s that actually matter. Here's how EPA and DHA differ, how much you need, and how to read a label so you know exactly what you're getting.

The short answer

What counts is the combined EPA + DHA per serving, not the total fish oil. Health Canada allows omega-3 products to provide 100 to 5,000 mg of EPA + DHA per day for adults. Products with at least 200 mg per day (in a balanced EPA:DHA ratio) can say they help maintain cardiovascular health (Health Canada fish oil monograph). If you eat oily fish twice a week, you may not need a supplement at all. If you don't, a daily product with a few hundred milligrams of EPA + DHA is a common starting point.

EPA vs DHA: what's the difference?

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the two long-chain omega-3s found in fish and seafood. They work together, but they're emphasized for different reasons:

A third omega-3, ALA, comes from plants such as flax, chia and walnuts. Your body converts only a small amount of ALA into EPA and DHA, so plant oils aren't a direct substitute for fish or algae omega-3s (NIH Office of Dietary Supplements).

How much omega-3 do you need?

From food: Canada's Food Guide has long recommended eating at least two servings of fish a week (about 150 g in total), choosing fish high in omega-3s and low in mercury, such as salmon, herring, sardines, char, Atlantic mackerel and rainbow trout (Health Canada).

From supplements: Health Canada's monograph sets out what licensed fish oil products can claim at each dose:

The upper end: both the European Food Safety Authority and the U.S. FDA consider up to about 5 g per day of EPA + DHA from supplements to be safe for adults (NIH ODS). Higher therapeutic doses, such as for triglycerides, should be guided by your doctor.

How to read an omega-3 label

This is where most people overpay. "Fish oil 1,000 mg" is the weight of the whole oil, not the omega-3s in it. Look at the medicinal ingredients and add up EPA and DHA:

• Example A: 1,000 mg fish oil providing 180 mg EPA + 120 mg DHA = 300 mg omega-3 per softgel.
• Example B: a concentrated softgel providing 600 mg EPA + 300 mg DHA = 900 mg omega-3 per softgel.

Product B gives three times the omega-3 per softgel, so fewer capsules for the same dose. To compare value, divide the price by the total EPA + DHA in the bottle, not by the number of softgels.

Choosing a format

• Softgels: convenient and the most common. Concentrated ("high potency" or "triple strength") versions mean fewer pills.
• Liquids: easy to take at higher doses or for people who dislike swallowing pills. Refrigerate after opening.
• Kids' formulas: lower-dose, flavoured liquids or chewables, often DHA-focused.
• Algae oil (vegan): a plant-based source of DHA, and often EPA, for vegetarians and vegans. Algae is where fish get their omega-3s in the first place.
• Cod liver oil: also provides vitamins A and D, so count those toward your daily total and avoid stacking it with other vitamin A supplements.

Getting the most out of it

• Take it with a meal, ideally one containing some fat. This can improve absorption and reduce fishy burps.
• Be consistent. Omega-3 levels build up over weeks of regular use.
• Check freshness. Store as directed, keep liquids refrigerated after opening, and don't use a product past its expiry date or if it smells strongly rancid.

Who should check with a professional first

• People taking blood thinners (such as warfarin) or with a bleeding disorder, since omega-3s can affect bleeding at higher doses
• Anyone scheduled for surgery
• People with a fish or shellfish allergy: consider an algae-based product and ask your pharmacist
• Pregnant or breastfeeding people choosing a prenatal DHA product
• Anyone considering high doses (above 3 g/day) or managing a heart condition

Common side effects are mild: fishy aftertaste, burping, heartburn or loose stools, which are usually reduced by taking omega-3 with food.

The bottom line

Read the label for EPA + DHA, not total fish oil. Eat oily fish twice a week if you can. If you supplement, a few hundred milligrams of EPA + DHA a day is a sensible baseline, and concentrated products mean fewer softgels. Talk to your healthcare provider about higher doses or if you take blood thinners. For more background, read our guide to fish oil benefits, side effects and precautions.

Shop omega-3s: fish oil options include NFH Trident SAP 66:33, Webber Naturals Triple Strength Omega-3, OmegAvail Hi-Po and Jamieson Wild Salmon & Fish Oil. Plant-based: A.Vogel VeganOmega3 and Webber Naturals Plant-Based Omega-3. For kids: allKiDz DHA Fish Smart. Or browse our Essential Fatty Acids & Oils collection and Heart Health collection.

This article is for general educational purposes and isn't a substitute for personalized medical advice. Read and follow the label, and speak with a healthcare provider before starting any new supplement, especially if you're pregnant, breastfeeding, take prescription medication or have a health condition.