Fish oil heavy metals: lab results by brand
Last reviewed October 2026.
All 10 IFOS-certified fish oils we track are marked compliant for mercury, lead, cadmium and arsenic on their public certificate (IFOS limits: mercury, cadmium and arsenic ≤ 0.1 ppm, lead ≤ 0.05 ppm). Mercury was below the lab's reporting limit in 10 of 10. The highest measured heavy-metal value was arsenic at 0.0456 ppm (Carlson The Very Finest Fish Oil, lot 0011224). Each value read from the product's own IFOS certificate on 2026-10-04.
Mercury, lead, cadmium and arsenic, by product
Results in ppm (mg/kg of oil), exactly as each certificate prints them. A value starting with “<” means the lab found less than its reporting limit, the number shown.
| Product | Mercury | Lead | Cadmium | Arsenic | IFOS compliant | IFOS certificate |
|---|---|---|---|---|---|---|
| Carlson Elite Omega-3 Gems | <0.0124 | <0.0066 | <0.0016 | <0.0066 | Yes | lot SB017377 |
| Carlson Super Omega-3 Gems | <0.0124 | <0.0066 | <0.0016 | <0.0066 | Yes | lot SB017012 |
| Carlson The Very Finest Fish Oil | <0.0121 | <0.0064 | <0.0016 | 0.0456 | Yes | lot 0011224 |
| Life Extension Super Omega-3 | <0.0123 | <0.0066 | 0.0020 | 0.0164 | Yes | lot C2600194 |
| OmegaVia DHA 600 | <0.0122 | <0.0065 | <0.0016 | <0.0065 | Yes | lot OV250191 |
| OmegaVia EPA 500 | <0.0123 | <0.0066 | <0.0016 | <0.0066 | Yes | lot OV250446 |
| OmegaVia Ultra Concentrated Omega-3 | <0.0124 | <0.0066 | <0.0017 | 0.0119 | Yes | lot OV250490 |
| Sports Research Triple Strength Omega-3 | <0.0124 | 0.0076 | <0.0017 | <0.02 (inorganic) | Yes | lot UC260228 |
| Viva Naturals Triple Strength Omega-3 | <0.002 | <0.1 | <0.002 | <0.1 | Yes | lot SG26050703 |
| Wiley's Finest Peak EPA (figures from lot 124068, which expired 02/2021; no current lot is published) | <0.005 | <0.02 | <0.01 | <0.05 | Yes | lot 124068 |
Arsenic is total arsenic except where marked inorganic, as each certificate states. Viva Naturals Triple Strength Omega-3 (lot SG26050703): the certificate prints lead as <0.1 ppm, a reporting limit above the 0.05 ppm specification, and marks it compliant. The printed figure alone does not show it is under 0.05 ppm. Wiley's Finest Peak EPA's certificate (lot 124068) prints a lead limit of 0.1 ppm, the IFOS limit at the time; current certificates print 0.05 ppm.
The limits: IFOS and GOED
IFOS prints its limit beside every result. The GOED Voluntary Monograph (version 9.1, issued 2026-07-23, read 2026-10-04) sets the industry's voluntary limits. Metals in ppm, which is mg/kg:
| Contaminant | IFOS limit | GOED limit |
|---|---|---|
| Mercury | 0.1 | 0.1 |
| Lead | 0.05 | 0.05 |
| Cadmium | 0.1 | 0.1 |
| Arsenic | 0.1 (as printed: total or inorganic) | 0.1 (inorganic) |
| PCBs | 45 ppb | 90 ppb (0.09 mg/kg) |
| Dioxins and furans | 1 ppt | 1.75 pg/g WHO-TEQ |
| Dioxin-like PCBs | 1.5 ppt | 3 pg/g WHO-TEQ |
PCBs and dioxins, by product
The same certificates, read 2026-10-04. PCBs in ppb (µg/kg); dioxins in ppt (pg/g), which the certificates that state a basis give as WHO-TEQ (2005); the certificates for Carlson Elite Omega-3 Gems, Carlson Super Omega-3 Gems, Carlson The Very Finest Fish Oil, OmegaVia DHA 600, Wiley's Finest Peak EPA print plain ppt.
| Product | PCBs | Dioxins and furans | Dioxin-like PCBs |
|---|---|---|---|
| Carlson Elite Omega-3 Gems | 0.369 | 0.0496 | 0.00842 |
| Carlson Super Omega-3 Gems | 0.364 | 0.193 | 0.0269 |
| Carlson The Very Finest Fish Oil | 0.351 | 0.166 | 0.00707 |
| Life Extension Super Omega-3 | 0.525 | 0.149 | 0.0475 |
| OmegaVia DHA 600 | 0.247 | 0.204 | 0.0115 |
| OmegaVia EPA 500 | 0.245 | 0.196 | 0.00778 |
| OmegaVia Ultra Concentrated Omega-3 | 1.08 | 0.106 | 0.0287 |
| Sports Research Triple Strength Omega-3 | 0.596 | 0.182 | 0.0398 |
| Viva Naturals Triple Strength Omega-3 | <5 | <1.0 | <0.5 |
| Wiley's Finest Peak EPA (figures from lot 124068, which expired 02/2021; no current lot is published) | 24.8 | 0.173 | 0.283 |
California Gold Nutrition: iTested reports
California Gold Nutrition is iHerb's house brand, tested under iHerb's own iTested programme, so it is not independent and is kept out of the tables above. Its reports print heavy metals in micrograms per serving against a column headed “US FDA Daily Limit”:
| Product | Serving | Arsenic | Cadmium | Mercury | Lead | Report |
|---|---|---|---|---|---|---|
| California Gold Nutrition Omega 800 | 1 softgel | 0.019 mcg | 0.003 mcg | 0.002 mcg | 0.011 mcg | lot UC190744, 2020-05-18 |
| California Gold Nutrition Omega-3 Premium Fish Oil | 2 softgels | <0.023 mcg | <0.011 mcg | <0.011 mcg | <0.011 mcg | lot UC190814, 2020-03-05 |
Limit column as printed on both reports: arsenic 130 mcg, cadmium 55 mcg, mercury 20 mcg, lead 75 mcg. Reports dated 2020-03-05, 2020-05-18; read 2026-10-04.
Brands with no heavy-metal numbers in a public registry
A USP Verified mark is pass/fail and publishes no measured heavy-metal values, and some bestsellers have no public certificate at all. What each of these brands does publish: Kirkland Signature, Nature Made, Solgar, Solaray.
Nordic Naturals: Not in a public registry that this site has read. Nordic Naturals has no IFOS lot report; NSF Certified for Sport lists Ultimate Omega 2X Sport and Ultimate Omega-D3 Sport (US listings, each with its lot numbers), not the regular Ultimate Omega (checked 2026-10-02), and that listing is pass/fail. Nordic Naturals says a Certificate of Analysis is available for each lot. That is the maker's own paperwork, not a public registry, and this site has not read one.
FAQ
Do fish oil supplements contain heavy metals?
In the 10 IFOS certificates we read on 2026-10-04, mercury was below the lab's reporting limit in 10 of 10, and the highest measured heavy-metal value was arsenic at 0.0456 ppm (Carlson The Very Finest Fish Oil, lot 0011224), against an IFOS limit of 0.1 ppm. 10 of 10 certificates mark all four metals IFOS-compliant. A certificate covers one tested lot.
Is Life Extension fish oil tested for heavy metals?
Yes, per lot, under IFOS. Life Extension Super Omega-3, lot C2600194: mercury <0.0123 ppm, lead <0.0066 ppm, cadmium 0.0020 ppm, total arsenic 0.0164 ppm, each marked IFOS-compliant (certificate read 2026-10-04).
Is Sports Research fish oil tested for heavy metals?
Yes, per lot, under IFOS. Sports Research Triple Strength Omega-3, lot UC260228: mercury <0.0124 ppm, lead 0.0076 ppm, cadmium <0.0017 ppm, inorganic arsenic <0.02 ppm, each marked IFOS-compliant (certificate read 2026-10-04).
Is Carlson fish oil tested for heavy metals?
Yes, per lot, under IFOS. Carlson Super Omega-3 Gems, lot SB017012: mercury <0.0124 ppm, lead <0.0066 ppm, cadmium <0.0016 ppm, total arsenic <0.0066 ppm, each marked IFOS-compliant (certificate read 2026-10-04). Carlson Elite Omega-3 Gems, lot SB017377: mercury <0.0124 ppm, lead <0.0066 ppm, cadmium <0.0016 ppm, total arsenic <0.0066 ppm, each marked IFOS-compliant (certificate read 2026-10-04). Carlson The Very Finest Fish Oil, lot 0011224: mercury <0.0121 ppm, lead <0.0064 ppm, cadmium <0.0016 ppm, total arsenic 0.0456 ppm, each marked IFOS-compliant (certificate read 2026-10-04).
Is Wiley's Finest fish oil tested for heavy metals?
Only an expired lot's IFOS results are public. Wiley's Finest Peak EPA, lot 124068: mercury <0.005 ppm, lead <0.02 ppm, cadmium <0.01 ppm, total arsenic <0.05 ppm, each marked IFOS-compliant (certificate read 2026-10-04). These figures come from lot 124068, which expired 02/2021; no current lot's certificate is published.
Is Viva Naturals fish oil tested for heavy metals?
Yes, per lot, under IFOS. Viva Naturals Triple Strength Omega-3, lot SG26050703: mercury <0.002 ppm, lead <0.1 ppm, cadmium <0.002 ppm, total arsenic <0.1 ppm, each marked IFOS-compliant (certificate read 2026-10-04). The lead figure is the lab's reporting limit, which is above the 0.05 ppm specification.
Is OmegaVia fish oil tested for heavy metals?
Yes, per lot, under IFOS. OmegaVia Ultra Concentrated Omega-3, lot OV250490: mercury <0.0124 ppm, lead <0.0066 ppm, cadmium <0.0017 ppm, total arsenic 0.0119 ppm, each marked IFOS-compliant (certificate read 2026-10-04). OmegaVia EPA 500, lot OV250446: mercury <0.0123 ppm, lead <0.0066 ppm, cadmium <0.0016 ppm, total arsenic <0.0066 ppm, each marked IFOS-compliant (certificate read 2026-10-04). OmegaVia DHA 600, lot OV250191: mercury <0.0122 ppm, lead <0.0065 ppm, cadmium <0.0016 ppm, total arsenic <0.0065 ppm, each marked IFOS-compliant (certificate read 2026-10-04).
Do Kirkland Signature and Nature Made publish heavy-metal results?
Not in a public registry. Their fish oils carry the USP Verified mark (USP list checked 2026-10-02), which is pass/fail: USP does not publish the measured heavy-metal values that an IFOS certificate prints.
Does Nordic Naturals publish heavy-metal results?
Not in a public registry that this site has read. Nordic Naturals has no IFOS lot report; NSF Certified for Sport lists Ultimate Omega 2X Sport and Ultimate Omega-D3 Sport (US listings, each with its lot numbers), not the regular Ultimate Omega (checked 2026-10-02), and that listing is pass/fail. Nordic Naturals says a Certificate of Analysis is available for each lot. That is the maker's own paperwork, not a public registry, and this site has not read one.
Related: what TOTOX means, with every product's value · third-party tested omega-3, explained · the best third-party-tested fish oil
This page summarizes published third-party testing data and makes no health, benefit, or treatment claims. A certificate describes one tested batch, not a permanent grade.
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