Does Nature Made Fish Oil Have Mercury?

December 20, 2025 •

3 min read

According to research from the National Institutes of Health, fish oil supplements, unlike certain types of fish, contain negligible amounts of mercury. Addressing a common consumer concern, Nature Made Fish Oil is a prime example of a product that undergoes a rigorous purification process designed specifically to remove heavy metals like mercury and ensure product purity.

Quick Summary

This article details Nature Made's commitment to safety, explaining their advanced purification methods like molecular distillation used to remove mercury and other contaminants from their fish oil. It clarifies why fish oil supplements pose minimal risk compared to some seafood, and highlights the importance of third-party verification from organizations like USP.

Key Points

Purified to Remove Mercury: Nature Made fish oil undergoes a meticulous purification process, such as molecular distillation, to actively remove mercury and other environmental contaminants.
Third-Party Verified: The products are independently tested and certified by the United States Pharmacopeia (USP), which sets strict purity standards for heavy metals like mercury.
Sourced from Wild-Caught Fish: The fish oil is sourced from wild-caught ocean fish, not farm-raised fish, and is processed according to Nature Made's high-quality standards.
Low Risk Compared to Whole Fish: Due to the refining process, fish oil supplements typically contain negligible or non-detectable levels of mercury, unlike some whole fish species that accumulate higher levels.
Safe for Long-Term Consumption: The rigorous purification and third-party verification make Nature Made fish oil a safe and reliable source of omega-3s for long-term use.

Understanding the Mercury Myth in Fish Oil

Mercury contamination is a significant health concern, particularly with larger, long-lived predatory fish such as swordfish and king mackerel, which accumulate higher levels of methylmercury throughout their lifespan. However, the risk associated with fish oil supplements is vastly different from consuming certain types of fish directly. The fish oil extraction and manufacturing process is specifically designed to isolate the beneficial omega-3 fatty acids while stripping away impurities. Concerns that fish oil supplements carry the same mercury risk as consuming contaminated fish are largely unfounded, especially with reputable brands like Nature Made.

The Science Behind Mercury Removal

Nature Made utilizes advanced, state-of-the-art purification processes to ensure their fish oil is safe and free of contaminants. The primary method for removing heavy metals and other toxins is molecular distillation.

What is Molecular Distillation?

Molecular distillation is a high-tech purification process that operates under reduced pressure (a vacuum) and at low temperatures.
Since mercury and other heavy metals have higher boiling points than the delicate omega-3 fatty acids, this process effectively separates the impurities from the oil.
This method is extremely efficient and ensures that the finished product contains undetectable levels of contaminants, providing a safe and clean source of omega-3.

Nature Made's Commitment to Quality and Purity

Nature Made's dedication to quality is a cornerstone of its brand. They source their fish oil from wild-caught ocean fish, not farm-raised fish, which are processed according to stringent quality standards. But beyond initial sourcing, their commitment is proven through third-party testing and verification.

Third-Party Verification Nature Made has more products verified by the United States Pharmacopeia (USP) than any other brand. The USP is a non-profit organization that sets public standards for dietary supplements, and their verification process involves:

Testing for potency and ingredient purity.
Auditing manufacturing practices for compliance.
Ensuring the product is free from harmful levels of contaminants, including mercury, PCBs, and dioxins.

The presence of the USP Verified mark on Nature Made's fish oil bottles is a clear indicator that the product has been tested and meets these strict standards for purity and quality.

Comparing Purity: Fish Oil Supplements vs. Whole Fish

When considering mercury risk, it is important to distinguish between consuming whole fish and taking a purified fish oil supplement. A comparison of these two omega-3 sources highlights the safety of high-quality supplements.


Feature	Wild-Caught Whole Fish	Purified Fish Oil Supplements (e.g., Nature Made)
Omega-3 Source	Comes directly from the fish's flesh.	Extracted and concentrated from the fish's oil.
Mercury Risk	Varies significantly depending on the fish species, age, and size; larger predators have higher levels.	Negligible to non-detectable levels due to purification processes like molecular distillation.
Contaminant Removal	No removal process; contaminants remain in the flesh.	Undergoes rigorous purification, including testing for mercury, PCBs, and dioxins.
EPA/DHA Concentration	Lower and less concentrated.	Often highly concentrated, requiring fewer servings to get a therapeutic dose.
Sustainability	Dependent on fishing practices and seafood consumption rates.	Uses small, oily fish lower on the food chain, often from sustainable populations.

Why Purification is Crucial for Supplement Safety

The purification process is what makes fish oil supplements a safer alternative to certain seafood choices, especially for vulnerable populations such as pregnant women. The refining of the oil ensures that consumers receive the benefits of omega-3s without the cumulative risk of heavy metal exposure. This critical step sets a safe supplement apart from potential risks found in a varied diet of whole fish.

Conclusion: The Final Verdict on Nature Made Fish Oil and Mercury

So, does Nature Made fish oil have mercury? Thanks to a comprehensive, multi-stage purification process, including molecular distillation, Nature Made's fish oil is purified to remove mercury and other environmental contaminants. The brand's products are tested and verified by third-party organizations like the USP, which adds another layer of consumer protection and assurance. For those seeking the health benefits of omega-3 fatty acids without the mercury concerns associated with consuming certain types of fish, a high-quality, verified supplement like Nature Made is a safe and reliable option.

Frequently Asked Questions

Yes, Nature Made fish oil is purified through a process called molecular distillation to effectively remove mercury and other contaminants to levels that are below detectable limits.

Molecular distillation is a advanced purification method that uses a vacuum and low heat to separate and remove heavy metals like mercury, PCBs, and dioxins from the fish oil, leaving behind pure omega-3 fatty acids.

You can be confident in Nature Made's safety because their products are verified by the United States Pharmacopeia (USP), an independent, non-profit organization that tests supplements for purity, potency, and quality.

No, fish oil supplements undergo extensive purification to remove contaminants, making the mercury risk significantly lower than that of consuming certain types of whole fish that accumulate higher mercury levels over their lifetime.

Nature Made sources its fish oil from wild-caught ocean fish, ensuring high-quality ingredients for their supplements.

Yes, in addition to mercury, Nature Made's purification process and USP verification include testing for other contaminants such as PCBs, dioxins, and furans.

While most reputable brands use some form of purification, it is best to look for a third-party certification like USP, IFOS, or a similar organization to ensure the product has been independently tested for mercury and other toxins.