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Omega-3 supplements, derived from various raw materials, are a popular source of essential fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Quality control measures are essential to ensure that omega-3 supplements meet stringent purity standards. Reputable manufacturers often employ molecular distillation processes and thorough testing to remove and minimize contaminants. Third-party certifications, like those provided by organizations such as the International Fish Oil Standards (IFOS), play a crucial role in verifying the quality and safety of omega-3 supplements.

Table of contents:

Raw Materials & Pollutants in Omega-3 supplements

The primary raw materials for these supplements include fish oil, algal oil, and krill oil. Fish oil is commonly obtained from fatty fish like salmon, while algal oil is sourced from algae, making it a suitable option for vegetarians and vegans. Krill oil, derived from small crustaceans known as krill, is another source rich in omega-3s.

However, the purity of these raw materials is a critical consideration. Contaminants such as heavy metals (e.g., mercury, lead), PCBs (polychlorinated biphenyls), dioxins, and other pollutants can potentially be present in the marine environments from which these raw materials are sourced. These contaminants may find their way into the omega-3 supplements during the extraction and processing stages.

Consumers are encouraged to choose omega-3 supplements from reliable brands with a commitment to quality assurance. Rigorous testing protocols, adherence to industry standards, and transparent sourcing practices contribute to the overall safety and efficacy of omega-3 supplements. However, as we, at MVS Pharma are in the process of creating a 100% clean and plastic free, high-quality raw material omega-3 supplement, in our competitve research, we saw many troubling findings. Untill now almost nobody is actively considering the substances of a the capsules that Omega-3 supplement brands are using. Many are either not disclosing this information on their labels, or it’s hard to find even on their official websites.

The bottom line is, that even if many of these companies do follow legally regulated amounts for contents of harmful and heavy metals, they are still exhisting in the capsule. Yes, they may be generally considered safe, but the law is different in each country and so are the varuables for how much of these harmful substances your omega-3 supplement should and can contain. So at the end of the day, you are taking in harmful substances with each capsule and in some cases (if the brand is not reliable) the benefits are vastly outweighted by the detriments.

The following list consists of raw materials and pollutants in most commercial Omega-3 supplements, which do not adhere to high quality raw material sourcing, manufacturing, packing and distributing processes.

As, Arsenic

Arsenic is a naturally occurring metalloid found in the Earth’s crust, with various inorganic and organic forms. Human activities, such as mining and pesticide use, can lead to environmental contamination. Arsenic is toxic and poses health risks, including skin lesions, cancer, and cardiovascular issues.  Exposure mainly occurs through contaminated water, food, and air. Regulatory agencies set acceptable levels to protect public health, such as the World Health Organization’s recommendation of 10 µg/L for arsenic in drinking water. Monitoring and controlling arsenic levels are crucial to minimize health risks and enforce safety standards.

Cd, Cadmium

Cadmium is a heavy metal found naturally but often released into the environment through industrial activities. Exposure can occur through inhalation, ingestion, and contact with contaminated sources, posing risks to the kidneys, lungs, and bones, as well as potential cancer development. Regulatory bodies set acceptable levels for cadmium in various environmental mediums, with the World Health Organization recommending a maximum of 3 µg/L in drinking water. Continuous monitoring is crucial to prevent excessive exposure and uphold safety standards.

Pb, Lead

Lead is a toxic heavy metal naturally present but released into the environment through human activities. Exposure poses health risks, particularly developmental and behavioral issues in children, and cardiovascular problems in adults. Regulatory standards, like the EPA’s 15 µg/L limit in drinking water, aim to mitigate lead exposure. Palladium, a rare transition metal, is not environmentally toxic in common uses, such as catalytic converters. While specific safety guidelines for palladium may exist in occupational settings, it lacks the widespread health concerns associated with lead.

Hg, Mercury

Mercury is a heavy metal released into the environment through human activities, with various forms such as elemental mercury and methyl mercury. Exposure can occur through inhalation, ingestion of contaminated fish, and contact with mercury-containing products. 

Mercury is known for its toxic effects on the nervous system, particularly harmful to fetuses and young children. Regulatory agencies set acceptable levels, such as the World Health Organization’s recommendation of 1 µg/m³ for elemental mercury vapor in indoor air. Continuous monitoring and control measures are essential to prevent excessive mercury exposure and minimize its harmful effects on human health and the environment.


DDT (dichlorodiphenyltrichloroethane) is a synthetic pesticide that was widely used in the mid-20th century but has been largely banned or restricted globally due to its persistence in the environment and harmful effects. Exposure to DDT can occur through soil, water, and food, with associated health risks including potential links to cancer and reproductive issues. Regulatory measures, including international agreements like the Stockholm Convention, aim to limit DDT use to protect the environment and public health. Efforts focus on finding alternative, less harmful pest control methods.


DDD (dichlorodiphenyldichloroethane) is a chemical compound formed as a breakdown product of DDT, a synthetic pesticide. Like DDT, DDD can persist in the environment, with exposure possible through soil, water, and food. Although generally considered less toxic than DDT, DDD still poses environmental and health risks. Monitoring and regulatory efforts are in place to manage its presence and address potential concerns.


DDE (dichlorodiphenyldichloroethylene) is a persistent environmental compound formed as a breakdown product of DDT, a synthetic pesticide. While less toxic than DDT, DDE can still pose environmental and health risks. It is found in soil, water, and food, with exposure possible through these sources. Regulatory measures aim to monitor and limit its presence, as part of efforts to manage persistent organic pollutants (POPs).


HCB (hexachlorobenzene) is a persistent environmental pollutant that was formerly used as a fungicide and pesticide. Its widespread use has been restricted due to concerns about its persistence, bioaccumulation, and potential health risks.  Exposure can occur through inhalation, ingestion of contaminated food, and contact with polluted soil. International regulations, such as the Stockholm Convention, aim to limit HCB use globally, focusing on minimizing environmental release and human exposure to safeguard public health and the ecosystem.


PCBs (polychlorinated biphenyls) are synthetic chemicals once widely used in industry but now largely banned due to environmental persistence and health risks. Exposure can occur through air, food, and water, leading to various health issues. International and national regulations aim to control PCB use, with efforts focused on monitoring, remediation, and reducing environmental contamination to safeguard public health.

Brominated flame retardants

Brominated flame retardants (BFRs) are chemicals added to products for fire resistance, but concerns about their environmental persistence and potential health risks have led to global regulatory restrictions. Exposure can occur through indoor air, food, and contact with treated products. Some BFRs are associated with health issues, prompting efforts to find safer alternatives. Regulatory measures focus on limiting specific BFRs to protect both human health and the environment.


DEHP (Di(2-ethylhexyl) phthalate) is a commonly used plasticizer to enhance flexibility in plastics, found in products like PVC plastics, medical devices, toys, and packaging. Exposure can occur through ingestion, inhalation, and skin contact, raising concerns about potential endocrine-disrupting effects. Regulatory measures restrict DEHP use, prompting efforts to find safer alternatives with less impact on human health and the environment.


Benzo(a)pyrene is a carcinogenic polycyclic aromatic hydrocarbon produced during incomplete combustion of organic materials. It poses health risks through inhalation, ingestion, and contact with combustion byproducts. Regulatory standards aim to limit its presence in the environment and products. Efforts focus on reducing emissions, monitoring air and food quality, and enforcing exposure limits to minimize associated health risks.

Sum 4 PAH

PAHs (polycyclic aromatic hydrocarbons) are considered dangerous for several reasons:

  1. Carcinogenicity: Certain PAHs, like benzo(a)pyrene, are known to cause or increase the risk of cancer, particularly lung cancer.
  2. Mutagenicity: PAHs can induce DNA mutations, raising the risk of cancer development.
  3. Endocrine Disruption: Some PAHs may disrupt hormone function, leading to reproductive and developmental issues.
  4. Toxicity to Organs: PAH exposure can harm organs, particularly the liver, causing damage and dysfunction.
  5. Environmental Persistence: PAHs resist breakdown, persisting in the environment, and can accumulate, posing ongoing risks to ecosystems and the food chain.
  6. Respiratory and Skin Effects: Inhalation and skin contact with PAHs can lead to respiratory and skin irritations.
  7. Source of Exposure: Commonly found in combustion products, PAH exposure is higher in urban areas and certain occupations.

Regulatory measures aim to control PAH levels to minimize health risks and environmental impact.

Dioxinlike PCBs

Dioxin-like PCBs (polychlorinated biphenyls) are a group of PCB congeners with structures similar to dioxins, known for their toxicity. They can cause cancer, disrupt the endocrine system, impair the immune system, and potentially have neurotoxic effects. Regulatory Agencies set acceptable rates for these PCBs in various environmental media, with limits expressed in toxic equivalent concentrations. Rigorous monitoring and enforcement are crucial to ensure compliance and protect human health and the environment.


Dioxins and furans, toxic environmental pollutants, pose health risks including cancer and reproductive issues. Persistent and resistant to breakdown, they accumulate in the food chain. Exposure occurs through contaminated food and air near industrial sources. Regulatory agencies set acceptable limits, often expressed as toxic equivalent concentrations (TEQ). Rigorous monitoring and control measures aim to enforce compliance, reduce emissions, and safeguard human health and ecosystems.

Dioxins+furans+dioxinlike PCBs

Dioxins, furans, and dioxin-like PCBs collectively pose serious environmental and health risks due to their high toxicity and persistence. Exposure occurs through contaminated food and air, primarily near industrial sources. Regulatory agencies set acceptable limits expressed as toxic equivalent concentrations (TEQ), and strict monitoring and control measures are essential to enforce compliance and reduce emissions, safeguarding human health and ecosystems.

Trans fatty acids

Trans fatty acids (TFAs) are unsaturated fatty acids, mainly from industrial processes like partial hydrogenation of oils. Found in baked and fried goods, they pose health risks, raising LDL cholesterol and contributing to cardiovascular diseases. Many countries regulate or restrict their use in food products to improve public health. Efforts focus on replacing TFAs with healthier alternatives in food processing.

There is no established daily tolerance or recommended daily intake for trans fatty acids (TFAs) because health authorities and nutrition experts recommend minimizing their consumption as much as possible.

Filler Ingredients

When manufacturing fish oil products, there is always some percent of filling material inside the capsules. Omega-3 capsules, like many other dietary supplements, often contain additional ingredients known as excipients or fillers. These ingredients serve various purposes, such as improving stability, enhancing absorption, or providing a suitable form for the supplement. Common fillers and excipients found in omega-3 capsules may include:

  • Glycerin: Glycerin is used to maintain the moisture content in the capsules and prevent them from drying out.
  • Purified Water: Water may be added to the formulation for various purposes, including maintaining the proper consistency of the ingredients.
  • Antioxidants: To prevent the oxidation of omega-3 fatty acids, which can lead to rancidity, antioxidants such as vitamin E (tocopherols) may be added.
  • Lemon Oil or Natural Flavors: Some manufacturers add natural flavors, typically from lemon oil, to mask the fishy taste or aftertaste that can be associated with omega-3 supplements.
  • Mixed Tocopherols: These are a group of compounds with vitamin E activity, and they are frequently added as antioxidants to protect the omega-3 fatty acids from oxidation.
  • Rosemary Extract: Another natural antioxidant, rosemary extract, may be used to help maintain the freshness and stability of the omega-3 oils.
  • Soy Lecithin: Soy lecithin is sometimes included to improve the dispersion of the omega-3 fatty acids, potentially aiding in absorption.

Why some Omega-3 supplements contain Vitamin A and E?

Some omega-3 supplements contain added vitamin A and E for several reasons, reflecting a comprehensive approach to nutritional supplementation:

  • Antioxidant Protection

Vitamin E, a potent antioxidant, is often included to protect the omega-3 fatty acids (EPA and DHA) from oxidation. The unsaturated nature of these fatty acids makes them susceptible to oxidative damage, leading to rancidity. Vitamin E helps counteract this process, maintaining the freshness and effectiveness of the supplement.

  • Synergistic Health Benefits

Vitamin A, known for its role in vision, immune function, and skin health, may be added to omega-3 supplements to provide a synergistic effect. The combination of omega-3 fatty acids with vitamin A can contribute to overall eye health and immune system support.

  • Stability and Shelf Life

Including antioxidants like vitamins A and E helps enhance the stability and prolong the shelf life of the omega-3 supplement. This is particularly important as it ensures that consumers receive the intended health benefits without the risk of consuming rancid or degraded fatty acids.

  • Comprehensive Nutritional Support

Some formulations aim to provide a more comprehensive range of nutrients. By combining omega-3 fatty acids with vitamins A and E, the supplement may offer a broader spectrum of health-promoting effects, potentially supporting various aspects of well-being.

  • Reducing Oxidative Stress

Omega-3 fatty acids themselves exhibit anti-inflammatory properties, and combining them with antioxidants like vitamins A and E may help reduce oxidative stress in the body. This combination is thought to provide a more holistic approach to supporting cardiovascular and overall health.

Capsule variants

Omega-3 supplements come in various capsule variants, each with its own characteristics. Here are some common capsule variants used for packaging omega-3:

1. Soft Gel Capsules (Soft gels)

 Soft gel capsules are a popular choice for omega-3 supplements. They are typically made of gelatin or other polymers and contain a liquid or gel-like form of omega-3 fatty acids.

  • Considerations: May not be suitable for those with gelatin allergies, and the gelatin itself may be of animal origin.

2. Enteric-Coated Capsules

Enteric-coated capsules have a special coating that prevents them from dissolving in the stomach. Instead, they release their contents in the small intestine.

  • Advantages:Minimizes the risk of fishy aftertaste or burps as the release occurs in the intestine, protecting against stomach acids.
  • Considerations: Typically more expensive, and the coating may contain additional ingredients.

3. Vegetarian/Vegan Capsules

Capsules made from plant-derived materials, such as cellulose or tapioca, suitable for vegetarian and vegan consumers.

  •   Advantages: Plant-based alternative to gelatin capsules, addressing dietary preferences and restrictions.
  •   Considerations: May have different dissolution characteristics compared to gelatin capsules.

4. Liquid-Filled Capsules

Similar to soft gel capsules, but with a liquid fill. These may be transparent or translucent.

  •   Advantages: Offers an alternative to traditional soft gels, allowing for the presentation of the liquid content.
  •   Considerations: Stability and potential leakage issues may arise.

5. Hard Gelatin Capsules

Capsules made of rigid gelatin and filled with powdered or oil-based omega-3 formulations.

  •   Advantages: Versatile for various formulations, and the rigid shell provides protection.
  •   Considerations: May not be suitable for those with gelatin allergies.

6. Chewable Capsules

Capsules with a chewable shell, providing an alternative for those who prefer not to swallow traditional capsules.

  •    Advantages: More palatable for some individuals, particularly those who have difficulty swallowing pills.
  •    Considerations: May contain additional ingredients for flavoring and texture.

7. Powder-Filled Capsules

Capsules filled with powdered omega-3 formulations.

  •  Advantages: Offers an alternative to liquid-filled or soft gel capsules, particularly for those who prefer powder formulations.
  • Considerations: Stability and dissolution characteristics should be considered.

When selecting an omega-3 supplement, consumers should consider their dietary preferences, potential allergens, and personal preferences regarding dosage form. Consulting with healthcare professionals is advisable for personalized recommendations.

Downsides of Softgel capsules

Despite the prevalence of soft gels for liquid encapsulation in the nutraceutical industry, this technology comes burdened with its own set of limitations. High moisture content, the incorporation of plasticizers and preservatives, incompatibility with high melting point excipients, coating difficulties, elevated rates of oxygen and gas permeability, and intricate processing pose significant challenges. To surmount these limitations, the emergence of liquid-filled hard capsule technology in the early 1980s marked a transformative step forward.

Why liquid-filled capsules are a wiser choice than softgel capsules?

Soft gels and hard gelatin capsules represent two pivotal technologies in the encapsulation process, each with distinctive features. Soft gels undergo a unified process, seamlessly combining capsule formation, filling, and sealing in a single step. Conversely, hard capsules are pre-fabricated, empty shells supplied to pharmaceutical or nutraceutical companies for in-house filling. This divergence in manufacturing processes prompts a closer examination of why liquid-filled hard capsules may be a wiser choice than their softgel counterparts. Here are the main reasons why:

Low Waste and Sourcing Efficiency

Softgel production is associated with higher waste levels due to the unified manufacturing process, leading to excess gelatin cut-offs. Hard capsules, sourced as pre-printed shells, minimize waste as they undergo stringent quality checks before in-house filling. This assures end-product manufacturers of the quality of capsules utilized in the encapsulation process.

Maintaining Product Efficacy

Softgel manufacturing introduces moisture through gelatin ribbon, potentially impacting moisture-sensitive molecules. Hard capsules, devoid of plasticizer and with lower moisture content, mitigate these concerns, ensuring stability for moisture-sensitive products.

Lower Oxygen Transmission/Permeability Rate

Hard capsules, lacking plasticizer, exhibit lower oxygen permeability compared to softgel capsules. This property enables hard capsules to contain highly odorous products, such as fish oil, valerian oil, and garlic oil, without compromising on odor.

No Dark Spots and Aesthetics

Softgel capsules may develop dark spots inherently during the encapsulation process, affecting the product’s visual appeal. Liquid formulation encapsulation in hard capsules with band-sealing eliminates this issue, enhancing product aesthetics and offering flexibility in color and pre-printed capsule options.

Convenient Processing for Low Melting Point Compounds

Hard capsules simplify the manufacturing process for materials with low melting points, allowing for easy mixing and filling. This is particularly beneficial for compounds that are liquid at room temperature, offering a more streamlined manufacturing approach.

Easy Filling of Hot Liquids and Flexibility of Combination Filling

Hard capsules provide the flexibility to be filled with hot liquids (up to 75 °C) and allow combination filling with ingredients in various forms, such as beads, microtablets, and pellets, along with the liquid formulation.

Choice of Vegetarian Dosage Form

Unlike softgel capsules, hard capsules are available in vegetarian form, made from HPMC (hydroxypropyl methylcellulose), a 100% plant-sourced cellulose.

Enhanced Bioavailability and Improved Stability

Liquid-filled hard capsules enhance the bioavailability of poorly water-soluble active ingredients, thereby increasing their effectiveness. Additionally, incorporating active ingredients into a hydrophilic or lipophilic matrix within hard capsules minimizes moisture sensitivity, improving overall stability.

In conclusion, the selection of liquid-filled hard capsules over softgel capsules presents a judicious choice, considering factors such as waste reduction, moisture sensitivity, oxygen permeability, aesthetics, and formulation flexibility. This encapsulation technology not only addresses manufacturing challenges but also offers a pathway to enhanced bioavailability and stability for nutraceutical products.

Additional advantages: According to various studies, liquid filled hard shell capsules have many advantages over soft gels. They contain 4-5 times less gelatine, require no additives, consist of water and gelatine only, are stable in hot climates – thereby do not stick together and become gluey like soft gelatine capsules. Furthermore, liquid filled hard shell capsules will disintegrate faster due to the capsule wall being 5 times thinner than the walls of soft gelatine capsules. This means there is less product migration into the shell, and less diffusion of odours. Also, there are no records of  liquid filled hard capsules having leakage or any other adverse reactions.

Omega-3 capsules packaging

In case a company uses soft gels for their fish oil product(s) and packages them in plastic container, there are many reasons why this is an outdated and dangerous practice. For example:

  • If there is one rancid fish oil capsule inside the packaging, during contact, it will contaminate all remaining capsules inside.
  • When one Soft gel capsule opens or breaks inside the packaging, it will go over the entire insides of the product. 
  • Every time you open the packaging, unless every capsule is inside a blister packaging, you will expose all the capsules to oxygen and start the oxidation process.
  • Many fish oil packagings aren’t completely protected against sunlight, or lack any protection at all.

That is why, we at MVS Pharma, choose to implement the best possible packaging technique to make sure each capsule stays fresh and safe until the moment you consume them! 

We use single hard capsule packing, meaning each of our capsules in individually packaged inside a paper box. This way, we don’t only avoid all the problems above, but also have several more advantages:

  •   Fully hygienic packaging of every capsule.
  •    The capsules do no stick to each other.
  •    You don’t expose all capsules, each time you want to get one.
  •    The remaining capsules always stay fresh.
  •    Easy to take just 1 or 2 capsules with you outside and to integrate in your daily eating plan.
  •    In case something happens to one capsule (it gets broken) it won’t spill in the whole packaging. 
  •    This ensures completely protection against sunlight and oxidation.

It’s important for you to check the product label for a complete list of ingredients, as formulations can vary among different brands and products.  Additionally, individuals with allergies or dietary restrictions should be mindful of ingredients like gelatin and soy lecithin. If there are concerns or specific dietary requirements, it’s advisable to consult with a healthcare professional or a registered dietitian before choosing an omega-3 supplement.

Disclaimer:As a service to our readers, MVS Pharma GmbH publishing provides access to our library of archived content – in our blog. Please note the date of last review or update on all articles. No content on this site, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.


Dr. Disha Trivedi

Dr. Disha Trivedi is PhD in Molecular Genetics and Biotechnology. She is working as a medical writer and researcher at MVS Pharma GmbH.