Shark Oil Benefits: Health Uses, Side Effects, and Dosage Guide

Shark oil, particularly shark liver oil, has been utilized for centuries in traditional Scandinavian medicine to address various health concerns. Today, this marine-derived supplement continues to gain attention for its unique composition and potential therapeutic properties. This comprehensive guide explores the evidence-based benefits, proper usage, and important safety considerations of shark oil supplementation.

Understanding Shark Oil and Its Components

Shark oil, commonly referred to as shark liver oil (SLO), is extracted from the livers of specific shark species, including deep-sea sharks, basking sharks, and dogfish sharks. These marine creatures produce oil rich in several bioactive compounds that contribute to its therapeutic potential.

The supplement typically appears as a dark yellow to brown liquid with a distinctive ocean-like aroma. Modern formulations are available in various forms, including liquid concentrates, softgel capsules, and as an ingredient in topical skincare products.

Key Active Compounds

Three primary components account for most of shark oil’s health-promoting properties:

• Alkylglycerols (AKGs): These naturally occurring lipids are also found in bone marrow, the spleen, and human breast milk. They play crucial roles in immune function and cellular health.
• Squalene: A hydrocarbon compound that serves as a precursor to cholesterol synthesis and provides antioxidant benefits. Dogfish sharks are particularly rich sources of this compound.
• Omega-3 Polyunsaturated Fatty Acids (PUFAs): Essential fats known for their anti-inflammatory properties and cardiovascular benefits.

Evidence-Based Health Benefits of Shark Oil

Immune System Enhancement

One of the most well-researched benefits of shark oil relates to immune function. The alkylglycerols present in the oil appear to activate macrophages—specialized white blood cells that identify and eliminate harmful substances and defective cells from the body.

Research involving older adults undergoing surgery demonstrated that supplementation with pure AKG capsules (500 mg twice daily) significantly increased antibody levels, reduced inflammatory markers, and decreased the occurrence of post-surgical complications. These findings suggest shark oil may help strengthen immune defenses, particularly during periods of physical stress.

Additionally, the squalene component acts as an immune enhancer, potentially improving the body’s response to various challenges. The omega-3 fatty acids further contribute through their well-documented anti-inflammatory effects.

Anticancer Research and Potential

Perhaps the most intriguing area of shark oil research involves its potential anticancer properties. Scientists have long been fascinated by the extremely low cancer rates observed in shark populations.

Laboratory studies suggest that alkylglycerols may offer anti-tumor potential through multiple mechanisms. They activate macrophages that can digest cancerous cells and exert anti-angiogenesis effects—meaning they may restrict the formation of new blood vessels that tumors need to grow and spread.

Squalene has shown promise in reducing inflammation caused by cancer treatments, suggesting it may serve as a supportive therapy during conventional cancer care. However, it’s crucial to note that most evidence comes from test-tube and animal studies. Human clinical trials are still needed to confirm these effects, and shark oil should never replace conventional cancer treatment.

Cardiovascular Health Considerations

The relationship between shark oil and heart health is complex, with research showing both potential benefits and concerns.

On the positive side, squalene demonstrates anti-atherosclerotic properties—meaning it may help prevent the buildup of plaque in arteries, a major risk factor for heart disease and stroke. Some studies suggest it accumulates in the liver where it may help regulate cholesterol and triglyceride production.

Animal research has shown that squalene supplementation can increase HDL (good) cholesterol levels. The omega-3 fatty acids in shark oil are well-established for reducing heart disease risk through multiple mechanisms.

However, contradictory evidence exists. Some studies indicate that high doses of squalene may actually increase total cholesterol and triglyceride levels. One study found that adults consuming high doses of shark liver oil experienced a 23% increase in total cholesterol levels and decreased HDL cholesterol.

These mixed findings suggest that dosage plays a critical role in shark oil’s effects on cardiovascular health. Anyone with existing heart conditions should consult their healthcare provider before using this supplement.

Skin Health and Protection

Squalene naturally comprises a significant portion of human sebum—the oily secretion that protects and moisturizes skin. Topical application of shark oil may provide several dermatological benefits:

• Enhanced skin hydration and moisture retention
• Protection against ultraviolet (UV) radiation damage
• Support for skin barrier function
• Potential anti-aging effects

These properties explain why shark oil and squalene appear as ingredients in various skincare products, including moisturizers, lip balms, and anti-aging creams.

Additional Potential Benefits

Preliminary research suggests shark oil may offer other health advantages:

• Fertility Support: Animal studies indicate that alkylglycerols may improve sperm motility and velocity, though human studies are lacking.
• Radiation Protection: AKGs may reduce tissue damage caused by radiation therapy, potentially benefiting cancer patients undergoing treatment.
• Oral Health: Some evidence suggests the immune-modulating effects of shark oil may reduce the frequency of recurrent mouth ulcers.

Proper Dosage and Administration

Currently, no standardized dosage recommendations exist for shark oil supplementation. Research studies have used varying amounts, making it difficult to establish universal guidelines.

One clinical study found that 500 mg taken twice daily before and after surgery improved immune markers and wound healing. However, adverse effects on cholesterol levels have been documented at doses of 15 grams per day or higher.

Most manufacturers recommend taking shark oil supplements with meals to potentially enhance absorption, though scientific validation of this practice is limited.

Important Dosage Considerations

• Start with the lowest effective dose
• Individual needs may vary based on health status and goals
• High doses may produce unwanted effects on blood lipid levels
• Always follow healthcare provider recommendations regarding duration and amount

Potential Side Effects and Safety Concerns

While shark oil is generally considered safe for most people when taken appropriately, several potential concerns warrant attention.

Cholesterol and Lipid Effects

As mentioned earlier, high doses of shark oil may negatively impact blood cholesterol profiles. Studies have shown increases in total cholesterol and triglycerides, along with decreases in beneficial HDL cholesterol at doses of 15 grams daily or more.

Individuals with existing cardiovascular disease, high cholesterol, or lipid metabolism disorders should avoid shark oil or use it only under medical supervision.

Respiratory Concerns

Older research has documented rare cases of lipoid pneumonia associated with shark liver oil supplementation. This condition occurs when oil enters the lungs, causing inflammation and breathing difficulties.

Liver Toxicity

At least one case report describes liver injury in a person taking two shark liver oil capsules daily for two weeks, resulting in toxic accumulation in liver tissue. While rare, this highlights the importance of proper dosing and medical oversight.

Heavy Metal Contamination

Sharks can accumulate mercury and other heavy metals from their ocean environment. However, research indicates that these contaminants concentrate primarily in muscle tissue and fins rather than liver oil. Manufacturing processes may further reduce mercury content to negligible levels, though quality control varies by manufacturer.

Drug and Supplement Interactions

While no definitive drug interactions have been conclusively documented, several theoretical concerns exist based on shark oil’s composition.

Blood Pressure Medications

The omega-3 fatty acids in shark oil possess blood pressure-lowering effects. When combined with antihypertensive medications, this may produce an additive effect, potentially causing blood pressure to drop too low.

Blood Thinning Medications

Omega-3 PUFAs affect blood clotting mechanisms. Theoretically, combining shark oil with anticoagulant medications like warfarin or antiplatelet drugs like aspirin could increase bleeding risk, though scientific evidence on this interaction remains mixed.

If you take any medications, particularly for cardiovascular conditions, discuss shark oil supplementation with your healthcare provider before starting.

Special Population Considerations

Pregnancy and Breastfeeding

Animal research suggests that shark oil supplementation during pregnancy may enhance immune function in offspring and increase immune factors in colostrum. However, no human studies have evaluated its safety or efficacy during pregnancy or lactation.

Due to insufficient safety data, pregnant and breastfeeding individuals should avoid shark oil supplementation unless specifically recommended by their healthcare provider.

People with Fish Allergies

Interestingly, shark oil may represent an alternative omega-3 source for some individuals with fish allergies. Cartilaginous fish like sharks appear to have lower allergenicity compared to bony fish among allergic individuals.

However, anyone with seafood allergies should exercise caution and consult an allergist before trying shark oil products.

Children

No research has specifically evaluated shark oil safety or appropriate dosing in pediatric populations. Children should not take this supplement without medical supervision.

Storage and Quality Maintenance

Proper storage is essential for maintaining shark oil quality and preventing oxidation. The omega-3 fatty acids in the oil are highly susceptible to rancidity when exposed to light, heat, and oxygen.

Storage Guidelines

• Keep bottles tightly sealed when not in use
• Store in a cool, dark location away from direct sunlight
• Refrigeration may extend shelf life, though some products are formulated for room temperature storage
• Use within three months of opening for optimal freshness
• Discard products that develop off-odors or flavors

Oxidized omega-3 supplements lose their therapeutic benefits and may potentially cause harmful effects, making proper storage critical.

Alternative Sources of Key Compounds

If shark oil isn’t suitable for you, or if you prefer alternative sources, the beneficial compounds found in shark oil are available from other sources.

Alkylglycerols

These immune-supporting lipids can be found in:

• Cow’s milk and dairy products
• Human breast milk
• Bone marrow
• Ratfish liver oil

Squalene

Plant-based sources of squalene include:

• Olive oil
• Amaranth oil
• Wheat germ oil
• Rice bran oil
• Palm oil

Omega-3 Fatty Acids

Numerous animal and plant sources provide omega-3s:

• Fatty fish (salmon, mackerel, sardines)
• Fish oil supplements
• Algae oil (vegetarian source)
• Flaxseeds and flaxseed oil
• Chia seeds
• Walnuts
• Hemp seeds

Environmental and Ethical Considerations

The sustainability of shark oil production raises important environmental concerns. Many shark species face threats from overfishing, habitat loss, and slow reproductive rates. Some shark populations have declined significantly, leading to ecosystem imbalances.

Consumers interested in shark oil should research manufacturers’ sourcing practices and look for products from sustainably managed fisheries or those certified by environmental organizations. Alternatively, choosing plant-based sources of squalene and omega-3s from algae may represent more sustainable options.

Making an Informed Decision

Shark oil presents a complex supplement choice with both potential benefits and legitimate concerns. While research supports several health-promoting effects—particularly regarding immune function—the evidence remains incomplete, especially for long-term use in humans.

Consider Shark Oil If:

• You’re seeking immune system support
• You want a concentrated source of squalene and alkylglycerols
• You’re looking for an alternative omega-3 source (and don’t have seafood allergies)
• You’ve discussed supplementation with your healthcare provider

Avoid or Exercise Caution If:

• You have cardiovascular disease or abnormal cholesterol levels
• You’re taking blood pressure or blood-thinning medications
• You’re pregnant or breastfeeding
• You have liver disease
• You have concerns about environmental sustainability

Conclusion

Shark oil offers a unique combination of bioactive compounds with promising health applications, particularly for immune support and potentially as an adjunct to cancer care. However, the mixed evidence regarding cardiovascular effects, limited human research, and potential for adverse effects at high doses necessitate a cautious, informed approach.

The most responsible use of shark oil involves consultation with a qualified healthcare provider who can assess your individual health status, medication regimen, and specific needs. They can help determine whether shark oil is appropriate for you and establish safe, effective dosing guidelines.

As with any dietary supplement, shark oil should complement—not replace—a healthy diet, regular exercise, and appropriate medical care. By making informed decisions and using supplements judiciously under professional guidance, you can maximize potential benefits while minimizing risks.

Sources:

• PubMed Central – National Institutes of Health
• PubMed – Biomedical Literature Database
• Office of Dietary Supplements – National Institutes of Health
• Mayo Clinic – Medical Research and Education
• WebMD – Health Information Resource