What are vegetarian Omega 3 capsules made of?

December 25, 2025 •

3 min read

Overfishing and sustainability concerns have increased the demand for plant-based supplements, leading to a rise in vegetarian omega 3 capsules. These products offer a viable alternative to traditional fish oil, but their ingredients can vary significantly depending on the target fatty acids.

Quick Summary

Vegetarian omega 3 capsules typically contain algal oil, a direct source of DHA and EPA, or plant oils like flaxseed rich in ALA. The capsule shells are usually made from non-animal materials such as tapioca starch or carrageenan.

Key Points

Source: Most high-quality vegetarian Omega 3 capsules are made from algal oil, a direct source of DHA and EPA.
ALA Conversion: Some vegetarian capsules use flaxseed oil, which provides ALA. However, the body's conversion of ALA to EPA and DHA is inefficient.
Capsule Shell: The outer shell is typically made from plant-based materials like carrageenan (from red seaweed) or modified starches (from corn/tapioca), rather than animal-derived gelatin.
Sustainability: Algal oil is a sustainable and environmentally friendly alternative to fish oil, as it does not contribute to overfishing.
Purity: Cultivating algae in controlled environments significantly reduces the risk of contaminants such as mercury and PCBs.
Additives: Common additives include antioxidants (e.g., rosemary extract) to prevent oxidation and rancidity, and flavorings to improve taste.

Sourcing Omega-3 Fatty Acids: Algae vs. Plant Seeds

While traditional omega-3 supplements are derived from fish, vegetarian capsules source their fatty acids from plant-based origins. The most advanced and direct vegetarian source is microalgae, which is the original source of the EPA and DHA found in fish. Another common source is flaxseed oil, which provides the precursor fatty acid ALA.

Algal Oil: The Direct Source of DHA and EPA

Microalgae, such as Schizochytrium sp., are cultivated in controlled, enclosed environments to produce oil rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). This approach is not only sustainable but also minimizes the risk of contaminants like mercury and PCBs, which can be present in fish. The oil is extracted and purified, providing a concentrated, vegan-friendly source of the same long-chain omega-3s found in fish oil.

Flaxseed Oil: A Common Source of ALA

Another popular plant-based source is flaxseed oil, which is exceptionally high in alpha-linolenic acid (ALA). The human body can convert ALA into EPA and DHA, but this process is highly inefficient. The conversion rate can be as low as 0.5–10%, meaning you would need a very high intake of ALA to produce sufficient levels of the more beneficial EPA and DHA. Other plant seeds, like chia and hemp, also contain ALA but do not offer a direct source of EPA and DHA.

Comparison Table: Algal Oil vs. Flaxseed Oil


Feature	Algal Oil (DHA/EPA Source)	Flaxseed Oil (ALA Source)
Primary Omega-3s	Contains pre-formed DHA and EPA.	Contains ALA, which the body must convert to EPA/DHA.
Bioavailability	High, as DHA and EPA are readily available.	Low, due to the body's inefficient conversion of ALA.
Conversion Needed	No, provides the required forms directly.	Yes, conversion to EPA and DHA is required.
Sustainability	Highly sustainable, grown in controlled systems.	Sustainable, but less effective for raising DHA/EPA levels.
Contaminant Risk	Very low, due to controlled cultivation.	Very low, sourced from crops.
Typical Cost	Often more expensive due to processing.	Generally less expensive.
Vegan Friendly	Yes, derived from microalgae.	Yes, derived from seeds.

Understanding the Capsule Shell

Just as important as the omega-3 source is the material of the capsule itself. Many traditional supplements use gelatin, an animal byproduct, to form the softgel. Vegetarian and vegan capsules avoid this by using plant-based alternatives.

Carrageenan and Modified Maize/Tapioca Starch: Common ingredients for creating a vegetarian softgel shell. Carrageenan is a gelling agent derived from edible red seaweed, while modified starches come from sources like corn or tapioca.
Vegetable Glycerin and Purified Water: These are typically included as humectants and solvents to ensure the capsule's consistency and stability.

Additional Ingredients and Formulations

To ensure product quality and consumer appeal, manufacturers often add other ingredients.

Antioxidants: Ingredients like rosemary extract, ascorbyl palmitate, and tocopherols are often added to protect the delicate omega-3 oils from oxidation and rancidity. Oxidation can degrade the oil's quality and produce unpleasant smells.
Flavoring: To prevent any off-putting tastes or 'burps,' some capsules include natural flavorings, such as peppermint oil.
High Oleic Sunflower Oil: This may be added as a carrier oil or to provide additional stability to the final product.

In conclusion, vegetarian omega 3 capsules are most often made from algal oil, a sustainable and direct source of beneficial EPA and DHA. Less effective, but still available, are capsules made from flaxseed oil, which requires the body to perform an inefficient conversion process. The vegetarian or vegan shell is typically crafted from plant-derived materials like modified starches or carrageenan, making the entire product suitable for those on a plant-based diet. For those seeking the most direct and potent source of marine-based EPA and DHA without consuming fish, algal oil is the optimal choice.

For more detailed information on omega-3 fatty acids and their health benefits, see the NIH Office of Dietary Supplements' fact sheet.

Frequently Asked Questions

Algal oil is derived from microalgae and is a direct, vegetarian source of the essential omega-3 fatty acids DHA and EPA, bypassing the need for fish.

While flaxseed oil is a good source of ALA, the body's conversion of ALA to DHA and EPA is inefficient, so algal oil is a more direct and reliable source for increasing these specific fatty acids.

The capsule shell is made from plant-derived materials like modified tapioca starch, carrageenan (from seaweed), and vegetable glycerin, as opposed to animal-based gelatin.

Yes, capsules made from high-quality algal oil provide both DHA and EPA, just like traditional fish oil supplements.

Yes, since the algae are typically cultivated in controlled environments, vegetarian capsules sourced from algal oil are free from the contaminants, like mercury, sometimes found in fish oil.

Antioxidants like rosemary extract are added to prevent the omega-3 oils from oxidizing or going rancid, which can affect the product's quality and taste.

You can check the product's nutritional information and ingredient list on the label. High-quality supplements will specify the amounts of DHA and EPA derived from algal oil.