Fish oil has many physical and mental health benefits, one of which may be to help reduce anxiety for some people.

Anxiety is a part of life. Whether yours is occasional or you have an anxiety disorder diagnosis, you might be looking for a way to reduce its impact.

Omega-3s are essential fatty acids that your body can’t produce, which means they must come from your diet. The main source of biologically active omega-3s is fish or fish oil supplements.

Fish oil is an extract of fat or oil from the tissue of fish. It’s usually from oily fish, such as:

  • tuna
  • herring
  • trout
  • sardines
  • mackerel

Cod liver oil is an example of oil sourced from fish liver.

Fish oil is extracted by a cooking, pressing, and purification process. The fatty acid composition can vary depending on the time of year and the type of fish used.

Fish oil is a dietary source of two important omega-3 fatty acids:

  • docosahexaenoic (DHA)
  • eicosapentaenoic acid (EPA)

The third omega-3 fatty acid is alpha-linolenic acid (ALA). It’s found in plant sources such as nuts and seeds and must be converted to DHA or EPA before providing any benefit other than energy.

There’s some evidence that fish oil’s omega-3 polyunsaturated fatty acids (PUFAs) might improve anxiety symptoms.

A 2018 review of 19 clinical trials found that fish oil may reduce anxiety. The people who received omega-3 PUFA treatment experienced less anxiety than control groups.

The omega-3 PUFA treatment benefited those with anxiety disorders than those without diagnoses.

The dose that helped the most was at least 2,000 mg per day. Lower doses didn’t have as much effect.

A 2011 study involving 68 medical students also showed the potential for PUFAs to reduce anxiety. Students who received 2,500 mg of omega-3 per day experienced a 20% reduction in their anxiety symptoms.

However, it was not clear in this study whether any of the students had been diagnosed with anxiety.

However, a 2019 review indicates that PUFAs may not improve conditions such as anxiety or depression. The doses given were lower than in other studies, which may account for the negative results.

There isn’t enough evidence to support replacing antidepressant or mood stabilizer medication with omega-3 fatty acids, according to the Royal College of Psychiatrists. However, fish oil may help when used in combination with medication.

Brain levels of DHA impact important processes such as glucose utilization and neurotransmission.

In other words, without the right amount of DHA, your brain is low on fuel and doesn’t send messages as well as it should.

This can cause issues with memory, learning, and anxiety. But regularly eating fish or taking a fish oil supplement may reverse these effects.

A 2015 study using mouse lemurs found that adding omega-3 PUFAs to their diet increased their performance in maze tests and reduced their signs of anxiety.

Another 2015 study suggests that DHA and EPA supplementation might ease anxiety by restoring gut microbiota. This is thanks to the gut-brain axis, which is two-way communication between your brain and spinal cord (central nervous system) and the neural circuits in your gastrointestinal tract (enteric nervous system).

The fatty acids from fish oil end up in your blood and cells, where they perform several important functions. They’re a source of energy and contribute to both structure and function of various tissue types.

DHA plays a key role in brain and eye development. It also affects mental health.

A 2020 literature review points to a connection between a low intake of omega-3s and:

DHA has an important impact because of the way it affects the function and fluidity of cell membranes, which:

  • protect cell contents
  • transfer in nutrients
  • transfer out wastes

As well as easing mental health symptoms, the PUFAs in fish oil may support your health in other ways.

  • Heart health: A 2018 study found that omega-3 fatty acids can lower heart rate, which may have a protective effect against heart disease. High doses of omega-3 fatty acids can also lower the levels of triglycerides, a fat that can increase the chance of heart disease when blood levels are too high.
  • Reduced inflammation: The effects of DHA and EPA on cell membranes can reduce inflammation, according to a 2017 study.
  • Weight loss: A 2018 study indicates that while fish oil supplementation has not yet shown benefits in terms of weight loss, it might improve the metabolic profile of people who are overweight or have obesity.
  • Skin health: Fish oil fatty acids may improve the skin’s role as a barrier, plus reduce inflammation, and speed up healing.
  • Pregnancy support: DHA supplementation in pregnancy may have multiple benefits, including preventing preterm labor and supporting the baby’s brain development. A 2016 study involving pregnant mothers and 695 of their children found that those who were exposed to fish oil supplementation in the third trimester had a reduced chance of asthma.
  • Bone health: A 2019 study indicates that DHA and EPA may protect against age-related bone loss by reducing the inflammation that causes some bone cells to be absorbed by the circulatory system.
  • Rheumatoid arthritis (RA): Omega-3 supplements may reduce symptoms of RA.

Sometimes eating fish produces more health benefits than taking a fish oil supplement. Possible reasons for this include:

  • Seafood may have other beneficial nutrients that are missing in fish oil supplements.
  • Benefits from seafood might be because it’s replacing less healthy food.
  • Evidence suggests that healthier lifestyles are associated with a seafood diet.

However, if you don’t get enough omega-3 fatty acids in your diet, you may be able to make up the difference with a fish oil supplement.

A word of caution

Health status varies by individual, so it’s advisable to speak with a professional before starting a new supplement regimen.

Supplements may have side effects or unwanted interactions with medications.

In addition, the quality and potency of commercially available supplements can vary greatly.

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There are a few simple ways to get the best out of your fish oil supplement:

  • Take fish oil with food to help it absorb into the body.
  • Reduce acid reflux by splitting your daily dose into two smaller portions.
  • Take it at the same time or times each day.

It doesn’t matter what time of day you take your supplement because the benefits of fish oil don’t happen right away. Instead, it may take several weeks for the DHA and EPA to accumulate before they take effect.

Fish oil is generally considered safe. When side effects occur, they’re usually mild. These can include:

  • headache
  • bad breath
  • unpleasant taste
  • heartburn
  • diarrhea
  • nausea

However, there are some things to be aware of before trying this supplement.

Fish oil may reduce blood clotting. For this reason, it’s a good idea to check with a doctor before using fish oil if:

  • you’re on blood-thinner medication, such as warfarin (Jantoven, Coumadin)
  • you use a nonsteroidal anti-inflammatory medication
  • you have surgery scheduled

Longer bleeding time may occur at doses ranging from 2 to 15 grams per day, according to the National Institutes of Health (NIH).

Daily doses of 900 mg of EPA or more and 600 mg of DHA or more taken over several weeks may weaken your immune system. This is because of the way high doses can suppress inflammation.

People with allergies to fish or shellfish may not be able to use fish oil.

Fish liver oil contains vitamins A and D along with omega-3 fatty acids. It’s crucial to monitor your total intake of these vitamins while taking fish liver oil because large doses can be toxic.

Taking high doses of omega-3 fatty acids may increase the chance of a heart condition called atrial fibrillation. Data from four trials revealed that a daily dose of 4 grams of omega-3s nearly doubled the occurrence of atrial fibrillation, according to a 2021 article.

On rare occasions, supplements and medications can have the opposite of their intended effect, and fish oil is no exception.

An example is outlined in a 2015 case report featuring a 54-year-old male who experienced worsening anxiety while using fish oil. He successfully managed depression using a combination of medication, psychotherapy, and fish oil. Still, He developed new anxiety over time that coincided with fish oil doses and disappeared when he stopped taking the omega-3 supplement.

Fish oil is an extract from the tissues of fatty fish and sometimes the liver of other fish such as cod. It contains two important omega-3 polyunsaturated fatty acids: DHA and EPA.

DHA and EPA are essential, which means your body can’t make them. Instead, you get them from dietary sources such as fish or fish oil supplements.

Omega-3 is one of the fatty acids your cells need for cell membrane structure and function. This means that adequate dietary intake of DHA and EPA is crucial in many ways.

Fish oil may help ease symptoms of anxiety. But not all natural remedies work for everyone.

If you’re looking for a natural remedy or additional treatment for anxiety, consider speaking with a healthcare or mental health professional to determine what is best for you and your symptoms.