Lawsuits over fish oil supplements have come in several waves, and the active ones target two things: whether chemically processed omega-3 concentrates can lawfully be sold as “fish oil,” and whether phrases like “supports heart health” on supplement bottles are false advertising. A separate round of litigation over PCB contamination was resolved by settlement in 2012, and federal regulators have pursued their own enforcement actions against unsupported marketing claims.
Heart Health Marketing Lawsuits
The newest and most active wave of cases, filed starting in 2024, goes after the heart health language printed on nearly every bottle of fish oil sold in the United States. Plaintiffs argue that claims like “Helps Support a Healthy Heart” are misleading because clinical research does not show that over-the-counter fish oil supplements prevent cardiovascular disease in the general population.
Nature Made (Pharmavite)
In January 2024, Guity Hamzeh filed a class action against Pharmavite LLC, which makes Nature Made supplements, in the U.S. District Court for the Northern District of California. The complaint alleged that marketing phrases such as “Helps Support a Healthy Heart” were false because no credible scientific evidence shows that over-the-counter fish oil supplements improve heart health or reduce disease risk.{1Bloomberg Law. Nordic Natural Hit With Heart Health Fish Oil False Ad Suit} The suit asserted violations of California’s False Advertising Law, Consumer Legal Remedies Act, and Unfair Competition Law, along with warranty and misrepresentation claims.
By mid-2026, the broader Nature Made class action had entered active settlement proceedings. A court granted preliminary approval of a settlement agreement, with a claims filing window expected to close before the end of 2026 and payments to class members anticipated in late 2026 or early 2027. Pharmavite has not admitted wrongdoing.{2Lawfold. Nature Made Class Action Lawsuit}
Costco (Kirkland Signature)
In November 2024, a class action was filed against Costco in the Southern District of California alleging that Kirkland Signature Fish Oil supplements were deceptively marketed as supporting heart health. The complaint in Costan v. Costco Wholesale Corp. cited research from the National Institutes of Health and JAMA Cardiology to argue that omega-3 supplements do not reduce cardiovascular events and may raise the risk of atrial fibrillation.{3ClassAction.org. Costco Lawsuit Alleges Kirkland Signature Fish Oil Supplements Don’t Support Heart Health as Advertised} The case remained pending as of mid-2026.{4Truth in Advertising. Kirkland Signature Fish Oil}
Nordic Naturals
Dayna Clark sued Nordic Naturals in July 2024 in the Northern District of California, alleging that the company’s fish oil capsules were falsely marketed as supporting heart health.{1Bloomberg Law. Nordic Natural Hit With Heart Health Fish Oil False Ad Suit} The court dismissed two of the original claims but preserved six others under California consumer protection and common law theories, and an amended complaint was filed in June 2025.{5The Brooks Institute. Nordic Naturals Initial Complaint}
Walmart (Spring Valley)
Walmart has drawn suits on this issue but secured an early win. In March 2024, Pearl Magpayo filed a class action in the Northern District of California alleging that Spring Valley Omega-3 Fish Oil products were deceptively marketed with heart symbols and “Heart Health” labeling, and that the products were missing an FDA-required disclaimer stating the evidence was “supportive but not conclusive.”{6ClassAction.org. Walmart Misrepresents Spring Valley Omega-3 Fish Oil Supplements Heart Health Benefits, Class Action Says} In October 2024, Judge William H. Orrick dismissed the lawsuit, ruling that the plaintiff’s theory was preempted by federal regulations and FDA guidance on how such health claims can be made.{7Bloomberg Law. Walmart Defeats Consumer’s Fish Oil Heart Health False Ad Suit} The ruling suggests that companies closely tracking FDA-approved claim language may have a stronger defense than those using broader marketing.
“Not Really Fish Oil” Ethyl Ester Lawsuits
Between 2021 and 2022, six class actions argued that many popular fish oil supplements aren’t actually fish oil. The chemistry at the heart of these cases is a process called trans-esterification, which converts natural omega-3 fatty acids into a synthetic form known as fatty acid ethyl esters. Plaintiffs argued the transformation is so fundamental that marketing the end product as “fish oil” misleads consumers.
Five of the six cases were dismissed.{8Nutritional Outlook. Frivolous Class Action Lawsuits Plague Omega-3 Industry} The best-known was Baines v. Nature’s Bounty, filed in New York in September 2021, which alleged that Nature’s Bounty 1400 mg fish oil capsules contained “not a single milligram” of the EPA and DHA omega-3 fatty acids found in fish.{9ClassAction.org. Nature’s Bounty Fish Oil Supplements Falsely Labeled, Class Action Alleges} The Second Circuit affirmed dismissal, ruling that the labeling would not “materially mislead reasonable consumers” and noting that the back label expressly stated the omega-3s were present “as ethyl esters.”{10Courthouse News Service. Second Circuit Axes Class Action Challenge Against Nature’s Bounty Fish Oil Supplements}
The one survivor of this wave is Hernandez v. Mimi’s Rock Corp., which targets the Dr. Tobias brand in federal court in California. In an August 2024 ruling, the court granted part of the defendant’s motion to dismiss but let the plaintiff try again; a third amended complaint was filed in September 2024.{11Justia. Hernandez v. Mimi’s Rock Corp.}
Walmart’s Spring Valley line was separately caught up in this wave through Corpuz v. Walmart Inc. in the Southern District of California, which alleged the product was a “lab synthesized solution” rather than genuine fish oil. In August 2023, Judge Ruth Bermudez Montenegro denied Walmart’s motion to dismiss.{12Courthouse News Service. Walmart Must Face Suit Over Deceptive Fish Oil Labeling} The case ended in March 2024 when the parties jointly moved to dismiss with prejudice, indicating a private settlement; the terms were not publicly disclosed.{13Bloomberg Law. Walmart Settles Deceptive Fish Oil Proposed Class Action Lawsuit}
The Science the Lawsuits Rely On
The heart health complaints draw heavily on the VITAL trial, an NIH-funded study published in the New England Journal of Medicine in 2018. It enrolled nearly 26,000 adults over 50 without a history of heart disease and found that one gram of omega-3 supplements daily “did not significantly lower the overall risk of major cardiovascular disease events.”{14NHLBI. Omega-3s Heart Health: Exploring Potential Benefits and Risks}
A 2024 analysis of UK Biobank data covering more than 415,000 participants, published in BMJ Medicine, found that among people without existing heart problems, regular fish oil supplement use was associated with a 13% higher risk of developing atrial fibrillation and a 5% higher risk of stroke. For people who already had heart disease, the picture was more mixed, with some potential benefits including a lower risk of progressing from atrial fibrillation to a heart attack.{15CNN. Fish Oil Supplement Dangers Study}
The National Heart, Lung, and Blood Institute has described the overall evidence as “nuanced, at best.”{14NHLBI. Omega-3s Heart Health: Exploring Potential Benefits and Risks}
FDA Rules Behind the Labels
The marketing at issue is governed by two different FDA frameworks, and the distinction matters for the lawsuits.
Under the Dietary Supplement Health and Education Act of 1994, manufacturers can make “structure/function claims” like “supports heart health” without FDA pre-approval. Labels must carry a disclaimer stating the FDA has not evaluated the claim and the product is not intended to diagnose, treat, cure, or prevent any disease, and manufacturers are supposed to have evidence that the claim is truthful.{16FDA. Structure/Function Claims}
A separate category called “qualified health claims” applies when evidence for a benefit exists but falls short of “significant scientific agreement.” In 2019, the FDA authorized qualified health claims linking EPA and DHA omega-3s to reduced risk of hypertension and coronary heart disease, but only when a product contains at least 0.8 grams of combined EPA and DHA per serving and includes mandatory qualifying language stating the evidence is “inconsistent and inconclusive.”{17FDA. FDA Announces New Qualified Health Claims for EPA and DHA Omega-3 Consumption and the Risk of Hypertension and Coronary Heart Disease} Several of the pending lawsuits allege that brands are using broad heart health marketing that implies more certainty than this framework permits.
FTC Enforcement
Federal regulators have pursued their own cases. In April 2021, the FTC settled charges against BASF SE and DIEM Labs over the marketing of “Hepaxa” and “Hepaxa PD” fish oil supplements. The companies had advertised the products as “clinically proven” to reduce liver fat in adults and children with non-alcoholic fatty liver disease, but a BASF-sponsored clinical trial had actually shown the supplements performed no better than a placebo. The companies agreed to pay more than $416,000 in consumer refunds, and the FTC ultimately distributed $396,431 to more than 1,800 consumers.{18FTC. FTC Approves Final Administrative Consent Orders Against Companies That Deceptively Marketed Fish Oil}{19State AG Report. FTC Sends Refunds to Consumers Who Bought Fish Oil Supplements Marketed With Unproven Health Claims} The consent order bars future health claims about omega-3 or liver-related supplements unless supported by evidence from randomized human clinical trials.
The PCB Contamination Case
An older wave of litigation targeted the product itself rather than the labeling. In March 2010, the Mateel Environmental Justice Foundation sued in California alleging that various fish oil products contained PCBs, industrial chemicals classified as probable carcinogens, without the warnings required by California’s Proposition 65. The suit initially targeted eight producers and retailers, including CVS, GNC, Rite Aid, and the makers of Nature Made and Solgar products. Testing of ten supplements reportedly found PCBs in all of them, with three exceeding California’s safety threshold.{20ABC News. Truth About Fish Oil Concerns}{21Seafood Source. Manufacturers Decry Fish Oil Lawsuit}
The Humboldt County Superior Court approved a settlement on February 1, 2012. Thirty companies affiliated with the omega-3 industry trade group GOED agreed to Proposition 65 limits for PCBs, dioxins, and related contaminants. Products meeting those standards could be sold in California without warning labels, and the settling defendants paid a total of $60,000 to cover the plaintiff’s legal costs.{22California Attorney General. Mateel Environmental Justice Foundation v. Aker Biomarine, et al.}{23NutraIngredients. GOED Settles Prop 65 Case for Omega-3 Products} The contamination issue has not generated significant class action activity since.
Where Things Stand
If you bought Nature Made fish oil, watch for the claims window in the Pharmavite settlement, which is expected to close before the end of 2026. The Costco and Nordic Naturals cases are still live. The ethyl ester labeling theory has largely failed in court, with the Dr. Tobias case the main exception. Walmart’s dismissal on federal preemption grounds signals that brands sticking to FDA-approved qualified health claim language are harder to sue than those using broader heart health marketing, and the outcomes of the remaining California cases will shape how that line is drawn.