Does Fish Oil Act as a Blood Thinner? Effects of Fish Oil

author avatar Dr. Eric Berg 01/27/2024

Does fish oil act as a blood thinner? Yes, fish oil can reduce blood clotting and helps keep the blood moving smoothly through the cardiovascular system, which lowers the risk of blood vessel disease and heart attacks. 

However, taking too much fish oil in combination with blood-thinning medication can prevent the formation of blood clots and increase the risk of excessive bleeding.

Discover five health benefits of fish oil and learn who should be cautious about taking fish oil supplements. 

Fish oil capsules

What is fish oil?

Fish oil is derived from the flesh of oily fish species such as anchovies, mackerel, salmon, trout, and sardines. 

Fish oil is an incredibly rich source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two omega-3 fatty acids with profound health benefits.

EPA and DHA play an essential role in brain health, eyesight, and immune system functions and have been found to lower the risk of heart disease, cancer, and chronic inflammation. 

Research published in Nutrients found that most people don’t consume enough fatty fish to maintain adequate EPA and DHA levels. 


Unsurprisingly, omega-3 fish oils have become one of the most popular dietary supplements in the U.S. and are widely available in liquid, capsule, and pill form.

Watch the video below to discover 15 signs of omega-3 fatty acid deficiency. 

Does fish oil act as a blood thinner?

EPA and DHA are incorporated into the cell membranes of platelets, a type of blood cell that regulates blood clot formation. This increases their membrane fluidity, which lowers the rate of platelet aggregation and blood clotting. 

EPA and DHA are natural blood thinners that can lower the risk of blood clots and help prevent thrombosis, pulmonary embolism, stroke, and coronary artery disease. 

While the blood-thinning effects of fish oils are generally considered a health benefit, individuals taking blood-thinning medication should avoid fish oil supplements due to an increased risk of excessive bleeding.

Research published in the Journal of Trauma Nursing found that fish oil supplements can augment the effects of anticoagulant drugs such as warfarin and can cause clinically significant bleeding and considerable blood loss.

However, it’s important to note that consuming oily fish while taking blood thinning medication isn’t associated with an increased risk of bleeding and that fish oil supplementation in healthy adults isn’t linked to impaired blood clotting.  

Woman holding fish oil supplement

5 reasons to take fish oil

The health-promoting effects of fish oils have been studied extensively, and evidence consistently confirms that adequate intake of omega-3 fatty acids is associated with a wide range of benefits.

Here are five reasons to take fish oil. 

1. Promote heart health

Omega-3 fatty acids have blood-pressure-lowering effects and help reduce elevated triglyceride and cholesterol levels, which supports healthy blood vessels and promotes effective blood pressure regulation.  

In addition, EPA and DHA are potent anti-inflammatory fatty acids that help reduce chronic inflammation associated with vascular damage and atherosclerosis. 

2. Lower inflammation 

Regular intake of fish oil is associated with a significantly lower risk of inflammatory conditions such as rheumatoid arthritis, inflammatory bowel disease (IBD), psoriasis, and asthma.


“The body can convert EPA and DHA into anti-inflammatory compounds,” explains Dr. Berg. “This helps resolve acute inflammation and lowers the risk of chronic inflammation linked to various detrimental health effects.” 

Woman measuring her waist

3. Help maintain a healthy body weight 

Omega-3 fatty acids can enhance insulin sensitivity and promote metabolic health, which lowers the risk of insulin resistance and other metabolic imbalances that can trigger weight gain.

Omega-3 fatty acids also play a role in stimulating the production of hormones involved in satiety regulation and may help minimize hunger and cravings.  

4. Lower the risk of depression 

Research published in Nature found that omega-3 fatty acids, especially EPA, can have profound benefits for the management of mood disorders and should be considered as a therapeutic tool for depression. 

It’s believed that EPA promotes the production of serotonin, a critical neurotransmitter that plays a crucial role in brain health and mood regulation. 

5. Promote radiant skin

Fish oils strengthen the skin’s natural barrier, which is vital to retaining moisture and protecting the skin against the potentially harmful effects of ultraviolet (UV) radiation and environmental pollutants.

EPA and DHA’s anti-inflammatory properties can help resolve skin inflammation and irritation, which promotes an even skin tone and may benefit the management of acne symptoms.  

Woman reading supplement label

How much fish oil should you take?

Many fish oil supplements contain between 1 and 2 grams of omega-3 fatty acids per serving, which is in line with general daily intake recommendations for healthy adults. 

However, in some cases, higher doses may be necessary to address specific health problems. 

The National Institutes of Health (NIH) suggests a daily fish oil intake of up to 4 grams for individuals with high triglycerides and cholesterol and those at risk of atrial fibrillation and other types of cardiovascular disease.      

Maintaining adequate EPA and DHA intake during pregnancy has been linked to a lower risk of preterm birth, preeclampsia, and gestational diabetes, and it’s recommended that pregnant mothers take a fish oil supplement that contains 120 milligrams of DHA and 180 milligrams of EPA per serving. 

However, it’s crucial to discuss fish oil supplementation with a healthcare provider to minimize the risk of potential drug interactions and side effects.

Man smelling his breath

Potential downsides of fish oil

Omega-3 fish oil supplements are generally considered safe and well-tolerated when taken in appropriate doses. 

However, fish oils can have an unpleasant fishy aftertaste and may cause bad breath, and taking fish oil supplements with food typically resolves these issues. 

Because fish oils can impact blood clotting, individuals taking blood thinners should avoid omega-3 supplementation. 

In addition, EPA and DHA have potential blood-pressure-lowering properties and may cause dangerously low blood pressure if combined with antihypertensive drugs or herbal supplements that help lower blood pressure.

Large species of oily fish can accumulate mercury and other environmental pollutants, and the quality of fish oil supplements can vary. 

To minimize your exposure to potentially harmful toxins, opt for high-quality fish oil supplements tested and certified by reputable organizations such as the United States Pharmacopeia (USP).

Fish oil supplement and fishtail

Key takeaways

Does fish oil act as a blood thinner? Yes, fish oil has blood thinning properties and can help prevent blood clots, which is associated with better cardiovascular health and a lower risk of embolism, thrombosis, and stroke. 

However, combining fish oils with blood-thinning medication can increase the risk of excessive bleeding, and it’s crucial to avoid fish oil supplementation if you are taking anticoagulant drugs. 


1. Can fish oil act as a blood thinner?

Yes, fish oils have blood-thinning properties and can play a role in preventing blood clots, which reduces the risk of embolism, thrombosis, coronary artery disease, and stroke.

2. Who should not take fish oil?

Fish oils can augment the effects of blood thinning medications, which increases the risk of excessive bleeding, and it’s recommended that individuals taking anticoagulant drugs such as warfarin avoid fish oil supplements.

Fish oils can lower blood pressure, and it’s crucial to discuss fish oil use with a healthcare provider if you take blood-pressure-lowering medications. 

3. What supplements are natural blood thinners?

Supplements such as fish oils, turmeric, ginger, ginkgo, white willow, vitamin E, nattokinase, and Asian ginseng have blood-thinning properties.  

4. Does fish oil increase the risk of bleeding?

While fish oil has been found to increase the risk of bleeding in individuals who are taking blood-thinning drugs, there is no evidence that fish oil supplementation is linked to impaired blood clotting or bleeding disorders in healthy adults.  

4. How much fish oil is safe to take?

Taking between 1 and 4 grams of fish oil daily has been found safe and is generally well-tolerated by most adults.  

6. Can you take fish oil with blood thinners?

No, it’s not recommended to combine fish oil with blood thinners as the omega-3 fatty acids in fish oil can impact blood clotting and result in an increased risk of excessive bleeding.  

7. Is fish oil good for your heart?

Yes, fish oil is good for your heart and can lower the risk of cardiovascular disease. 

Fish oils promote healthy blood pressure and balanced blood lipid levels and have potent anti-inflammatory properties, all of which are associated with a lower risk of cardiovascular diseases such as high blood pressure, heart attacks, and stroke. 






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