What fish is vascepa made from? A guide to its origins and purification

December 4, 2025 •

4 min read

While many assume Vascepa is just another fish oil supplement, it is actually a highly purified, single-molecule prescription medication with a specific purpose. The active ingredient, icosapent ethyl, is derived from the oil of specific fish, which undergoes a rigorous process to isolate it for therapeutic use.

Quick Summary

Vascepa's active ingredient, icosapent ethyl, is derived from the oil of sardines and anchovies through a high-purity process, distinguishing it from conventional, over-the-counter fish oil supplements.

Key Points

Source Fish: Vascepa is derived from the purified oil of specific small, oily fish, primarily sardines and anchovies.
Purified Ingredient: Its active ingredient is a highly purified, single molecule called icosapent ethyl (EPA), not a mix of omega-3s like standard fish oil.
FDA Regulation: The manufacturing process for Vascepa is stringently regulated by the FDA, ensuring a high level of purity and consistency.
Unique Composition: Unlike many OTC supplements, Vascepa contains only EPA, which is significant because DHA (found in many supplements) can increase LDL-C levels.
Prescription Only: Vascepa is a prescription medication and should never be substituted with over-the-counter fish oil supplements.
Clinical Benefits: It is prescribed to lower high triglycerides and, in specific high-risk patients, to reduce cardiovascular events like heart attack and stroke.

The Core of Vascepa: Icosapent Ethyl

At its core, the prescription drug Vascepa is composed of one active ingredient: icosapent ethyl (IPE). This is a highly purified and modified form of eicosapentaenoic acid, or EPA, which is a type of omega-3 fatty acid. The key to Vascepa's unique profile lies in this purification, which differentiates it significantly from the vast majority of over-the-counter (OTC) fish oil products. Unlike many dietary supplements that contain a mix of different omega-3s, Icosapent ethyl is specifically and exclusively EPA. This exclusivity is central to its therapeutic efficacy and its distinct clinical outcomes.

The Fish Behind the Formulation

So, what fish is Vascepa made from? The answer is specific and points to a sustainable sourcing method. The oil used to produce Vascepa is extracted from small, oily fish, with sardines and anchovies being the primary sources. These fish are rich in the omega-3 fatty acids required for the manufacturing process. By targeting these specific, readily available species, the manufacturer can ensure a consistent and reliable supply of the raw material needed for their highly controlled process.

Not Your Typical Fish Oil: A Matter of Purity

One of the most important aspects to understand about Vascepa is that it is explicitly not considered a standard fish oil, despite its origin. The difference lies in the extensive manufacturing process designed to achieve a level of purity not found in general OTC supplements. This purification is what allows it to function as a precisely dosed, FDA-regulated medication.

The Process of Purification:

Extraction: Oil is first extracted from the sourced fish, such as sardines and anchovies.
Molecular Isolation: Through a complex, regulated process, the eicosapentaenoic acid (EPA) molecule is isolated from other omega-3s, including docosahexaenoic acid (DHA).
Esterification: The isolated EPA is then converted into its ethyl-ester form, icosapent ethyl.
Impurity Removal: This stringent process removes other fatty acids, as well as potential contaminants and impurities that can sometimes be found in less-regulated dietary supplements.

Comparison: Vascepa vs. OTC Fish Oil


Feature	Vascepa (Prescription)	Over-the-Counter Fish Oil (Supplement)
Active Ingredient	Highly purified icosapent ethyl (EPA only)	A mix of different omega-3 fatty acids, including both EPA and DHA
Purity & Consistency	Subject to stringent FDA regulation for consistency and purity	Not subject to the same strict regulation; purity and content can vary widely
Effect on LDL-C	Does not raise "bad" cholesterol (LDL-C) levels	Formulations containing DHA can potentially raise LDL-C levels
Therapeutic Use	FDA-approved for specific indications, such as reducing cardiovascular risk in high-risk patients	Sold for general health support; no FDA approval for specific diseases
Sourcing	Reliably sourced from sardines and anchovies	Sourced from a wider variety of oily fish (salmon, herring, mackerel, etc.)

The Therapeutic Role of Vascepa

Vascepa is prescribed for specific, clinically proven uses, most notably for people with elevated triglyceride levels. It is often used as an adjunct to statin therapy to reduce the risk of cardiovascular events, such as heart attack and stroke, in patients with established cardiovascular disease or diabetes with additional risk factors. The precise mechanism for this cardiovascular benefit is still being studied, but it is believed to involve multiple pathways beyond just lowering triglycerides.

Potential Considerations for Patients

Because Vascepa is derived from fish, patients with known allergies to fish or shellfish should inform their doctor. While the purification process is extensive, caution is still advised. Furthermore, Vascepa can increase the risk of bleeding, especially when taken with other anticoagulant or antiplatelet medications. It is a potent medication that requires a prescription and should not be used interchangeably with dietary fish oil supplements. The manufacturer's website provides additional information on its use and indications.

Conclusion

In summary, Vascepa is made from the highly purified oil of sardines and anchovies, but it is a specialized prescription medication that is chemically distinct from over-the-counter fish oil. The stringent manufacturing process isolates a single molecule, icosapent ethyl (EPA), removing impurities and other omega-3s like DHA. This difference in purity and composition is what enables its specific, FDA-approved therapeutic effects in lowering high triglycerides and reducing cardiovascular risk, a benefit not supported by evidence for general fish oil supplements. Patients should always consult their healthcare provider to understand if Vascepa is the right treatment for their condition and never substitute it with an OTC product.

The Difference in Cardiovascular Protection

Prescription icosapent ethyl (Vascepa) has been shown in clinical trials, such as the REDUCE-IT trial, to significantly reduce the risk of major adverse cardiovascular events in certain patient populations. This outcome is not linked to over-the-counter fish oil supplements, which lack the same high concentration and purity of EPA. The inclusion of DHA in most OTC products can be problematic for patients with high LDL-C, whereas Vascepa does not raise LDL levels. This clinical evidence is a fundamental reason why the two products are not interchangeable and require a doctor's supervision.

A Final Word on Substitution

The misconception that all fish oil is the same can lead to significant patient harm. The FDA classifies Vascepa as a drug, not a dietary supplement, a distinction that regulates its manufacturing, content, and claims. Attempting to replicate the therapeutic effects of Vascepa by taking large quantities of OTC fish oil is not only ineffective but also potentially risky due to inconsistent dosing, purity issues, and potential side effects. Therefore, proper medical guidance is essential when considering treatment for high triglycerides or cardiovascular risk.

Visit the official Vascepa website for more information on the medication and its use

Frequently Asked Questions

No, Vascepa is not the same as over-the-counter fish oil supplements. While it is derived from fish, it is a highly purified, single-molecule prescription medication containing only icosapent ethyl (EPA), while OTC supplements contain a less-refined mix of different omega-3 fatty acids, including DHA.

Vascepa is made from the oil extracted from specific small, oily fish. The primary fish species used are sardines and anchovies.

A fishy aftertaste or burping is a common side effect of some fish oil supplements, but studies on Vascepa have shown common side effects to include muscle and bone pain, swelling, and constipation, rather than a fishy taste.

Vascepa undergoes a complex FDA-regulated manufacturing process to isolate and purify the single active ingredient, icosapent ethyl (EPA), removing impurities and other omega-3s. Regular fish oil supplements are not subject to these same standards and contain a mixture of fatty acids.

Because Vascepa is derived from fish, patients with a known history of fish or shellfish allergies should exercise caution. It is essential to inform your doctor about any fish or shellfish allergies before starting Vascepa.

No, you should not take both Vascepa and additional fish oil supplements unless advised by your doctor. Your doctor can determine the correct dosage and combination for your specific health needs.

The stringent FDA-regulated manufacturing process for Vascepa is designed to eliminate impurities and potential toxins that can sometimes be found in less-regulated fish oil supplements. This results in a product of high purity and quality.