Products · Omega-3 & fish oil · Kirkland Signature (Costco)
Kirkland Signature Fish Oil 1000 mg
Reader ratings
The lowest-cost fish oil we looked at, with 250 mg of EPA plus DHA a softgel and a USP Verified claim on Costco’s page. We have not confirmed the USP listing, and no oxidation figure is published.
Best for Costco members who want a low-cost fish oil at a dose near the 250 to 500 mg a day in our dosing guide, and who are fine with porcine gelatin and a product that contains soy.
- Our quality rating
- Fair (3 of 5)
- Price range
- Budget
- Size
- 400 softgels (one softgel twice a day); Costco item 926628
approx. $21 for 400 softgels
See it on Kirkland Signature (Costco)’s site →We are not affiliated with Kirkland Signature (Costco). This link goes to the maker’s own page, with no tracking code. How we're funded.
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How we evaluated it
Why we chose it What put it on our list
- The dose fits our sources and dosing guide: one softgel has 250 mg of EPA plus DHA, and the label directs one softgel twice a day, which is 500 mg.
- Costco’s page says the oil is United States Pharmacopeia (USP) Verified and describes the mark as checking the label amounts and contaminants such as heavy metals and pesticides. We have not seen USP’s listing.
- The label names the fish, anchovy and sardine, and the ingredient list is short: fish oil concentrate, gelatin, glycerin, water and tocopherol. It says the product contains fish and soy.
- At the page price of $20.99 for 400 softgels, it costs about $0.05 a softgel, or about $0.11 per 500 mg of EPA plus DHA, against about $0.19 for the budget IFOS-listed oils we list (Sports Research and Viva Naturals).
Trade-offs What to weigh before you buy
- The USP claim is unconfirmed. USP’s verified-products site returned an access error to our automated fetches, so we could not look the product up. We found no recall or FDA warning letter for it.
- The label gives EPA and DHA together (250 mg), not each, and publishes no oxidation (TOTOX) figure or lot report. Costco’s page says “sustainably sourced” and “wild-caught ocean fish” and that mercury is below 0.1 parts per million, without naming a certifier or a lab.
- The softgel is made with porcine gelatin, and the product contains fish and soy. You need a Costco membership to buy it in a warehouse. The price is Costco.com’s listed price, and warehouse prices may differ. The label says to consult a physician if you have bleeding problems or take anything that affects blood clotting; our dosing guide calls extra bleeding risk theoretical, not confirmed up to 4 g a day.
What to know Details worth knowing first
Kirkland Signature’s fish oil is the lowest-priced fish oil we looked at, and its dose per softgel is the closest we found to the 250 to 500 mg a day in our dosing guide. Costco’s page says it is USP Verified, which would give it an independent check, but we have not been able to open USP’s directory to confirm it, and we are asking about it.
The remaining gaps are no published oxidation figure, no separate EPA and DHA amounts and no named sustainability certifier. Until the listing is confirmed, the IFOS-listed oils on this site have the stronger evidence, at a higher price per softgel and a higher dose per capsule.
Check with a clinician before taking fish oil if you use blood thinners or have atrial fibrillation (see omega-3 and heart health).
Quality & testing How it measures up against our checklist
- Third-party tested
- No
- Tested by
- USP Verified (claimed on Costco’s page; not confirmed)
| What we checked | What we found |
|---|---|
| Independent testing (USP Verified) Maker’s claim | Costco’s page says “United States Pharmacopeia (USP) Verified”, and a 2020 label in NIH’s label database shows the seal “USP Dietary Supplement Verified”. USP’s own Kirkland Signature brand page in a 2016 Internet Archive copy listed “Natural Omega-3 Fish Oil 1000 mg Softgels”, but that is ten years old, and USP’s current directory refused our automated check. The product is not in the IFOS registry or in NSF’s Certified for Sport directory. |
| Freshness (TOTOX at or under 26) Not verified | No oxidation figure published. |
| Stated EPA and DHA Maker’s claim | 250 mg of EPA plus DHA per softgel, given as one combined figure, plus 50 mg of other omega-3s, from the supplement facts text on Costco’s page. |
| A named source and sustainability certification Maker’s claim | Anchovy and sardine are named. “Sustainably sourced” has no certifier named. |
| Lot or best-by date Not verified | Not shown on Costco’s page; it will be on the bottle. |
What the labels mean
- Verified We opened an independent record that confirms it: a certifier’s listing, a regulator’s list or a lab report. It is linked under Sources.
- Maker’s claim The maker says so on its own page or label. We read it but found no independent record.
- Not verified We looked and could not confirm it, or the maker does not say. Treat it as unknown.
Sources Where our facts come from
- Costco: Kirkland Signature Fish Oil 1000 mg, 400 Softgels. Maker’s page. Supplement facts text, ingredients, allergens, the USP Verified claim and the $20.99 page price as seen 2026-10-22. Shown as unavailable online. Costco is the brand owner. Open ↗
- NIH Dietary Supplement Label Database: Kirkland Signature Fish Oil 1000 mg, label 239474. Independent source. A federal database copy of a 2020 label (item 926628): the USP seal, 300 mg total omega-3 per softgel and the blood-thinner caution. It shows what the label says. It is not a test. Open ↗
- USP Verified brand page for Kirkland Signature (Internet Archive copy, 2 September 2016). Certifier or regulator listing. Ten years old. Lists “Natural Omega-3 Fish Oil 1000 mg Softgels” among Kirkland Signature’s USP Verified products in 2016. It does not show today’s status. Open ↗
Alternatives Other options to compare
- Sports Research Alaskan Omega-3 Fish Oil About $0.36 a softgel with an IFOS lot report we could read, but a higher dose: about 950 mg of EPA plus DHA per softgel.
- Viva Naturals Triple Strength Omega-3 Fish Oil IFOS and Labdoor lot reports, at about $0.19 per 500 mg of EPA plus DHA, roughly twice Kirkland’s cost. Two softgels give about 2,070 mg.