Fish oil is often a practical choice when you want a higher amount of EPA and DHA at a lower cost, while krill oil provides these fatty acids in a different molecular form that may influence how your body processes them.
Understanding their composition, absorption, and clinical evidence can help you choose a supplement that suits your nutritional needs.
Shop Now: OptiKrill Krill Oil + Fish Oil Omega-3
Krill Oil vs Fish Oil: Key Differences
Both oils provide EPA and DHA. EPA supports heart health and inflammation pathways, while DHA supports brain and retinal membranes. Better absorption alone does not prove better health outcomes.
The table compares their sources, EPA+DHA content, forms, and cost.
| Feature | Fish oil | Krill oil |
|---|---|---|
| Marine source | Oily fish such as anchovies, sardines, and mackerel | Antarctic krill (Euphausia superba), a small crustacean |
| EPA+DHA per 1,000 mg oil | 300–600+ mg | 120–250 mg |
| Omega-3 form | Triglycerides, re-esterified triglycerides or ethyl esters | Mainly phospholipid-bound |
| Absorption evidence | Depends on the form and fat in the meal | Human studies report mixed bioavailability results; dose matters |
| Other compounds | May contain added vitamin E | Naturally contains astaxanthin, though amounts vary |
| Allergens | A concern for people with fish allergies | A concern for people with shellfish or crustacean allergies |
| Tolerability | Can cause fishy burps, reflux, or gastrointestinal upset | May cause fewer fishy burps for some people; tolerance varies |
| Cost for the same EPA+DHA dose | Usually lower | Usually higher |
What is EPA and DHA?
EPA and DHA are the two main omega-3 fats found in both fish oil and krill oil.
- EPA supports heart health and normal inflammatory pathways.
- DHA is an important structural fat in the brain and retina.
The main difference is not that one source has “better” EPA or DHA. It is the amount and form provided per serving.
- Fish oil often provides a higher EPA and DHA dose per capsule, especially in concentrated formulas.
- Krill oil provides EPA and DHA alongside phospholipids, but may contain a lower total EPA and DHA amount per serving.
Is Krill Oil Better Absorbed Than Fish Oil?
Krill oil is frequently promoted as having superior absorption because much of its EPA and DHA is associated with phospholipids.
These phospholipids participate in cell membrane structure and may influence how omega-3 fatty acids are transported and distributed after digestion.
For a wider view of evidence-led nutritional choices, explore our guide to choosing longevity supplements.
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How Does Omega-3 Absorption Differ?
Omega-3 Forms: Phospholipids, Triglycerides and Ethyl Esters
Some of krill oil’s EPA and DHA are carried by phospholipids. Fish oil provides these fats as triglycerides, re-esterified triglycerides, or ethyl esters. The chemical form matters more than the source.[2][5]
Take omega-3 supplements with a meal containing fat to help absorption. Ethyl ester formulations are particularly sensitive to the meal’s fat content. The dose and how well you digest fat also affect how much EPA and DHA reaches your bloodstream.[2][3][5]
What Human Absorption Studies Show
Human studies report mixed results. Some suggest that krill oil is absorbed better at lower doses, while re-esterified triglyceride fish oil can match or exceed its absorption at higher doses. Higher short-term plasma levels do not prove better long-term omega-3 status or health outcomes.[4][5]
People who digest fat less well, including some older adults and people without a gallbladder, may absorb phospholipid-bound omega-3s more readily.[5] Choose a formulation based on your digestion capacity rather than marketing claims.
The label matters too: EPA and DHA amounts can vary widely.
How Much EPA and DHA Is in Each Serving?
Check the nutrition panel, not just the front label.[3][2] Compare the combined EPA+DHA per serving, then work out the cost. The number on the front of an omega-3 pack can be misleading. A product labelled “1,000 mg fish oil” may provide far less than 1,000 mg of the EPA and DHA you are actually looking for. To compare supplements properly, check the nutrition panel for the separate EPA and DHA amounts per serving, add them together, then assess what that dose costs across the full pack.
Two Hypothetical Supplement Labels
Two labels can provide different EPA+DHA doses. Label A: 1,000 mg oil with 180 mg EPA and 120 mg DHA = 300 mg EPA+DHA. Label B: 500 mg oil with 250 mg EPA and 150 mg DHA = 400 mg EPA+DHA.
Calculate EPA+DHA and cost per 100 mg
Start with the serving size on the label: one serving may contain more than one capsule.
EPA+DHA per pack = EPA+DHA per serving × servings per pack.
Cost per 100 mg = pack price × 100 ÷ total EPA+DHA per pack.
For example, a ₹1,999 pack with 60 servings, each providing 500 mg EPA+DHA, contains 30,000 mg in total. The cost per 100 mg is ₹6.66.
Use this calculation to compare krill oil tablets or fish oil supplements.
Beyond the dose, check added compounds, quality testing, and safety.
Krill Oil Tablets vs Fish Oil Capsules: Which Should You Choose?
| Your priority | What to consider | Practical direction |
|---|---|---|
| Higher EPA+DHA per serving | Compare the declared EPA and DHA amounts | A concentrated fish oil may be more convenient |
| Phospholipid-based omega-3 | Examine the formulation and research | Krill oil is an option |
| Lower cost per mg of EPA+DHA | Compare serving sizes and prices | Fish oil is often more economical |
| An alternative to conventional fish oil | Consider source, tolerance, and personal preference | Krill oil may be suitable |
How to read an omega-3 supplement label
Before buying, check these five points:
- EPA content: The amount of eicosapentaenoic acid in milligrams.
- DHA content: The amount of docosahexaenoic acid in milligrams.
- Serving size: Whether the listed quantities apply to one or several capsules.
- Source and form: Fish oil, krill oil, algae oil, triglycerides, ethyl esters, or phospholipids.
- Quality information: Evidence of contaminant testing, oxidation control, manufacturing standards, and transparent ingredient sourcing.
For comparison, calculate the cost per 500 mg of EPA+DHA rather than comparing prices per bottle or per 1,000 mg of total oil.
These criteria are similar to those used when evaluating the quality and bioavailability of supplements.
Check Testing, Labels and Storage
Ask for third-party reports covering contaminants, source traceability, and oxidation markers such as peroxide, anisidine, and TOTOX, where applicable. GOED recommends a TOTOX value below 26.[2][3]
Read the ingredients, storage instructions, and expiry date. Store the oil in a cool, dark place, as directed on the label.[3][4]
Allergies, Side Effects and Medicines
Avoid krill oil if you have a crustacean allergy, and fish oil if you have a fish allergy. Both may cause reflux, bad breath or stomach upset. Take the oil with a meal.[3][4][7]
Speak to a clinician before use if you take anticoagulants or antiplatelets, are pregnant or breastfeeding, or have surgery planned. If you’re preparing for surgery, ask whether you should stop taking it 1–2 weeks beforehand.[3][4][6]
With these safety checks covered, compare dose, cost, and tolerability.
Choosing Krill Oil or Fish Oil
Once you’ve checked dose, absorption, and safety, compare value based on your EPA+DHA needs. Choose by EPA+DHA dose, not capsule size. Start with your dietary intake and health goal, then check how much EPA+DHA the daily serving provides.[3][5]
Match the dose to your goal. Absorption data alone does not prove better clinical outcomes. For higher EPA+DHA needs, fish oil is often easier to dose and usually costs less per gram.[4][5]
Compare cost per 100 mg of EPA+DHA rather than bottle price. Also check the formulation, tolerability, suitability for your allergies, medication precautions, and quality testing documents.[3][5]
Use these checks for any product, including OptiKrill.
Check the serving size, capsule count, amounts of krill oil, EPA and DHA per serving, listed astaxanthin, allergens, storage instructions, and warnings. Use these details and the current price to calculate the cost per 100 mg of EPA+DHA.
Do not calculate EPA or DHA content from the total oil amount or assume better absorption without product-specific evidence. A label-based check is the only reliable way to assess dose and value.
FAQs
Does krill oil have more EPA and DHA?
Both krill oil and fish oil supply EPA and DHA, but the amounts vary by formulation. Check the label for the milligrams of EPA and DHA, not just the total oil content.
At matching EPA and DHA doses, both oils work well at increasing blood omega-3 levels. Fish oil usually costs less per milligram of EPA and DHA.
Does krill oil contain astaxanthin?
Yes, krill oil naturally contains astaxanthin, an antioxidant. The amount varies, and its presence alone does not prove added clinical benefits.
How do I choose between krill oil and fish oil?
Both provide EPA and DHA, but their omega-3 forms and EPA+DHA amounts per serving differ. A 4-week double-blind study found comparable plasma and red blood cell EPA+DHA levels at matched doses. Krill oil is not always better absorbed [1].
Choose krill oil for its phospholipids and astaxanthin, or if it suits your digestion better. Fish oil usually costs less for higher EPA+DHA targets.
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