Krill oil supplement: what you get per softgel and who should skip it
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- Krill oil 500 mg softgel. Best for: Adults without a seafood allergy who want a small daily omega-3 dose. See options on Amazon
- Double strength krill oil, 1,000 mg softgel. Best for: Adults who want fewer softgels for the same krill oil amount. See options on Amazon
- Krill oil 2,000 mg per serving. Best for: Adults who want more krill-based EPA and DHA a day. See options on Amazon
- Fish oil softgel instead. Best for: People who want the most EPA and DHA per softgel. See options on Amazon
What krill oil is
Krill oil comes from krill, which supplement labels list as a shellfish. It is sold as a supplement source of the long-chain omega-3s EPA and DHA, alongside fish oil, cod liver oil and algal oil, as the NIH Office of Dietary Supplements (ODS) lists them.
Two things make krill oil different from fish oil:
- Phospholipids. ODS says krill oil contains omega-3s primarily as phospholipids. Fish oil omega-3s occur naturally as triglycerides.
- Astaxanthin. Krill oil labels often list esterified astaxanthin as a separate line. NOW Foods lists 360 mcg per 1,000 mg serving.
Because it comes from a shellfish, krill oil labels carry a shellfish allergen statement. NOW Foods' label says "Contains shellfish (krill)" and tells people with a seafood allergy not to use it.
Krill oil vs fish oil: omega-3s per gram
The size on the front of the bottle is the amount of oil, not the amount of omega-3. Compare EPA and DHA on the Supplement Facts panel instead.
| Per 1,000 mg of oil | EPA | DHA |
|---|---|---|
| Krill oil (NOW Foods label) | 135 mg | 60 mg |
| Typical fish oil (NIH) | 180 mg | 120 mg |
So gram for gram, a krill oil softgel usually delivers less EPA and DHA than a typical fish oil capsule. NOW Foods lists 250 mg of total omega-3 fatty acids and 450 mg of phospholipids per 1,000 mg of krill oil.
Many Amazon listings advertise 2,000 mg of krill oil per serving. That usually means two or more softgels, so check the serving size before comparing.
Is krill oil absorbed better?
This is the main claim made for krill oil. ODS gives a balanced answer: some studies suggest the phospholipids in krill oil have somewhat higher bioavailability than the omega-3s in fish oil, whereas other studies do not.
ODS also notes that all forms of omega-3 supplements, including natural triglycerides, re-esterified triglycerides, free fatty acids and ethyl esters, significantly increase EPA and DHA levels in the blood. The ethyl ester form is absorbed somewhat less well than the others.
The practical takeaway: a possible absorption edge does not clearly make up for the lower omega-3 content per gram. If your goal is a specific amount of EPA and DHA, total milligrams on the label still matter most.
How much omega-3 do you need?
ODS sets adequate intakes for omega-3s as ALA, the plant form: 1.6 g a day for adult men and 1.1 g for adult women. It does not list a separate daily target for EPA and DHA.
No upper limit is set for omega-3s. FDA has concluded that supplements providing no more than 5 g a day of EPA and DHA are safe when used as recommended, and the European Food Safety Authority found long-term intake up to about 5 g a day appears safe. Krill oil doses on most labels are far below that.
Safety: allergies, blood thinners and pregnancy
- Seafood or shellfish allergy. Do not take krill oil. NOW Foods' label says not to use it if you have a seafood allergy.
- Blood thinners. NOW Foods advises talking to a physician if you take anticoagulant or anti-platelet medicines. ODS says fish oil might prolong clotting times with warfarin, although most research at 3 to 6 g a day of fish oil found no significant effect on anticoagulant status.
- Pregnancy and nursing. The NOW label is for adults only and advises talking to a physician if pregnant or nursing. ODS lists an EFSA suggestion that pregnant women get an additional 100 to 200 mg a day of DHA, which a clinician can help you plan.
- Mercury. ODS reports omega-3 supplements have not been found to contain methyl mercury, because it is removed during processing.
How to choose a krill oil supplement
- Read EPA and DHA in mg. Ignore the oil weight on the front and compare the omega-3 lines.
- Check the serving size. A 2,000 mg serving may be two or four softgels.
- Look for phospholipids listed. Labels that state phospholipids in mg show the phospholipid form krill oil is sold for.
- Check the shell. Many softgels use bovine gelatin.
- Consider fish oil or algal oil instead if you want more EPA and DHA per softgel, or if you have a shellfish allergy. ODS says algal oil usually provides around 100 to 300 mg DHA.
What to look for when you buy
Krill oil 500 mg softgel
Best for: Adults without a seafood allergy who want a small daily omega-3 dose
Small softgels you can take one or two at a time. NOW Foods' 500 mg version uses a 2 softgel serving that adds up to 1,000 mg of krill oil.
Watch out: Low omega-3 per softgel, so read EPA and DHA per serving, not per softgel. Not for anyone with a seafood or shellfish allergy.
See options on AmazonDouble strength krill oil, 1,000 mg softgel
Best for: Adults who want fewer softgels for the same krill oil amount
One softgel gives the same 1,000 mg that takes two smaller softgels. NOW Foods lists 135 mg EPA, 60 mg DHA and 450 mg phospholipids per 1,000 mg softgel.
Watch out: Larger softgel to swallow. Talk to your doctor first if you take anticoagulant or anti-platelet medicines.
See options on AmazonKrill oil 2,000 mg per serving
Best for: Adults who want more krill-based EPA and DHA a day
Gives twice the krill oil of a 1,000 mg serving, so twice the EPA and DHA of the same formula.
Watch out: Usually means two or more softgels per serving. Check the serving size and EPA plus DHA total before assuming it is stronger.
See options on AmazonFish oil softgel instead
Best for: People who want the most EPA and DHA per softgel
NIH says a typical 1,000 mg fish oil capsule gives about 180 mg EPA and 120 mg DHA, more than krill oil per gram.
Watch out: Not suitable for fish allergies. Lacks the phospholipid form and astaxanthin that krill oil labels advertise.
See options on AmazonQuestions people ask
- Is krill oil better than fish oil?
- Not clearly. NIH says some studies suggest krill omega-3s are absorbed somewhat better and others do not, while krill oil usually carries fewer omega-3s per gram than typical fish oil.
- Are krill oil supplements safe?
- For most adults at label doses, yes. Skip it if you have a seafood or shellfish allergy, and ask your doctor first if you take a blood thinner or are pregnant.
- How much krill oil should I take?
- Follow the label serving, often 1,000 to 2,000 mg of krill oil a day. FDA considers up to 5 g a day of combined EPA and DHA from supplements safe when used as recommended.
- Can I take krill oil with a shellfish allergy?
- No. Krill are shellfish, and labels such as NOW Foods' say not to use krill oil if you have a seafood allergy. Algal oil is a non-seafood option.
- What is astaxanthin in krill oil?
- It is a compound krill oil labels list separately, often as esterified astaxanthin. NOW Foods lists 360 mcg per 1,000 mg serving, with no Daily Value established.
Sources
- Omega-3 Fatty Acids: Fact Sheet for Health Professionals (ods.od.nih.gov), NIH Office of Dietary Supplements
- Krill Oil 500 mg Softgels (www.nowfoods.com/products/supplements/krill-oil-500-mg-softgels), NOW Foods
- Krill 1000, Double Strength 1,000 mg Softgels (www.nowfoods.com/products/supplements/krill-1000-double-strength-1000-mg-softgel), NOW Foods