Can You Take Too Much Fish Oil: Side Effects & Alternatives

Can You Take Too Much Fish Oil: Side Effects & Alternatives


Fish oil is often touted as the best dietary solution for obtaining healthy essential fats, but it is not the only way. Although fish oil is a popular method for obtaining essential fats like omega-3 polyunsaturated fatty acids, it may have multiple side effects that can minimize its potential health benefits.

At the same time, many plant sources of these same nutrients are available. The growth of these sources of healthy fats provides a promising hope that fish oil can become a less-necessary part of our diets and give way to more nutrient-dense, more sustainable options.

What Is Fish Oil?

Can You Take Too Much Fish Oil: Side Effects & Alternatives

Fish oil is oil that is extracted from fish tissues. Fish oil most often comes from naturally oily fatty fish. Eating fish like trout, mackerel, tuna, herring, salmon, shellfish, and sardines is one way to gain omega-3s. Fish oil and supplements are often divided into fish oil supplements and liver oil supplements. 

Because of its high content of healthy fats, fish oil is sometimes viewed as an important supplement to add to one’s diet and can potentially offer multiple health benefits in doing so.

What Are the Benefits of Fish Oil?

Fish oil is rich in omega-3 fatty acids, which provide the most effective form of nutrition in fish oil. The high concentration of omega-3s can provide many benefits for several of the body’s systems. These fatty acids can help support heart health, cognitive function, and eye health. 

Fish oil can provide two of the important omega-3 fats that are less abundant in a typical diet: EPA and DHA. Fish oil contains higher doses of these fats than almost any other supplement.

What Are Omega-3s?

Algae Oil Omega-3 Supplements

Omega-3 fatty acids are the building blocks of cells and cell membranes in our bodies. Omega-3s are polyunsaturated fats that can play a key role in supporting cell receptors and cell behavior. There are three types of omega-3s:

  • Eicosapentaenoic acid (EPA)
  • Docosahexaenoic acid (DHA)
  • Alpha-linolenic acid (ALA)

All three of these fatty acids are important to include in one’s daily diet, but most people do get enough ALA from food alone. ALA is abundant in a standard diet since it can be found in many nuts, seeds, and oils. The body can create the more crucial types of omega-3s by converting ALA into EPA and then DHA, but it can only do so in very small amounts.

The body can convert these two fatty acids with very limited capability. EPA and DHA fatty acids are abundant in types of seafood, so they are often referred to specifically as marine omega-3s.

Because the body can only convert very small amounts of EPA and DHA, and because these fatty acids are only available in a few food sources, supplementation of these two types of omega-3s is important. 

ALA can be thought of more so as an omega-3 precursor than true omega-3 itself. EPA and DHA are the two omega-3s that your body really needs, and fish oil does not contain ALA.

What Are the Side Effects of Too Much Fish Oil?

Despite its benefits, including too much fish oil in one’s diet can have several potential side effects. Everyone may respond differently to taking in regular amounts of fish oil, so you should monitor your body’s reaction and take note if you experience any side effects of fish oil. You should speak with your healthcare provider if you have any concerns about fish oil dietary supplements.

The following are some of the most common side effects of consuming high doses of fish oil.

Acid Reflux

Acid Reflux

Fish oil is not known to be the most pleasant supplement on the market due to its smell and taste. Unfortunately, the discomfort many times does not end once the fish oil goes down. Fish oil can cause uncomfortable acid reflux, leading to nausea, discomfort, bad breath, and unpleasant fishy burps. 

It can be challenging to avoid this side effect altogether, as the best solution is to minimize dosage or take the supplement with food to decrease adverse effects and possibly relieve accompanying indigestion. This phenomenon is linked to the way fish store omega-3s in their body: as triglycerides. The triglyceride form of omega-3 is not water soluble, so fish oil typically sits on the surface of the liquid in the stomach, causing these undesirable after-effects.


At this point, it may be clear that fish oil is not the ideal source of omega-3s if you are trying to avoid digestive system issues. If you can steer clear of the uncomfortable effects of acid reflux, fish oils may come to get you later in the digestive process. 

Higher doses of fish oil may increase the chance of diarrhea, so it is important to monitor how much you are taking.

Vitamin A Toxicity

Although not often considered a common side effect, vitamin A toxicity is a real risk. Some fish oils, like cod liver oil, contain high amounts of vitamin A. In one serving, fish oil can provide over twice as much vitamin A than you need, putting you at an increased risk of experiencing side effects. 

Side effects of vitamin A toxicity include dizziness, nausea, skin problems, and joint pain. To avoid any issues from consuming too much vitamin A, you should closely observe how much of the vitamin is in the supplements you take and limit the amount of fish you oil you consume. The upper daily limit for vitamin A intake is around 10,000 IU.

Low Blood Pressure

Some people believe that sources of omega-3 support healthy blood pressure. Consuming large amounts of fish oil could lead to heart health complications

As a result, those with preexisting health conditions requiring anticoagulants like blood thinners or who have trouble with blood sugar should speak with their healthcare professional. Your doctor can suggest dietary guidelines and carefully monitor any intake of fish oil to avoid possible unwanted side effects from high doses of omega-3 in those with certain conditions.

What Are the Best Alternatives to Fish Oil?

Fish oil is unique in that it provides a considerable amount of DHA and EPA fatty acids, which are hard to come by. Since a standard diet is typically rich in ALA, finding healthy, sustainable sources of these other two necessary fatty acids can be challenging.

Omega-3 Fortified Eggs

Omega-3 fortified eggs are developed by feeding flax seeds to chickens. Eggs fortified with omega-3 are the only food besides seafood that provides DHA and EPA fatty acids. However, just because eggs are labeled as being fortified with omega-3 doesn't mean that sustainability or humane standards have been met--a similar issue as for large-scale factory fishing operations.

Plant-Based Sources

Plant-based sources of omega-3s generally only offer ALA, so they do not provide the perfect substitute to fish oil. However, your body converts some small amounts of ALA into EPA and DHA, so plant-based sources can still help incrementally towards achieving your daily need for true omega-3.

Plant-based sources of ALA omega-3 include walnuts, chia seeds, flax seeds, and plant oils. To obtain supplementation of EPA and DHA specifically in your diet, then you may be better served to explore other options.

Algae Oil


Algae oil is produced by extracting oil from multiple species of microalgae. The types of microalgae that are used to produce the oil are very rich in DHA and EPA fatty acids. Algae oil provides a promising alternative to fish oil that tastes better, has the same nutritional benefits, and is more sustainable, providing healthy omega-3s without taking fish out of the ocean.

Fish are considered to be some of the largest sources of omega-3s like EPA and DHA, but surprisingly, fish do not produce these fatty acids on their own. Instead, fish become rich in these fatty acids because they consume microalgae, which naturally provide DHA and EPA entirely on their own. Therefore, algae oil is a great alternative to fish oil without sacrificing nutrients.


For those on a plant-based diet, algae omega-3 supplements can be the most convenient and viable option since other plant-based options are often rich in ALA but do not allow for a sufficient intake of DHA and EPA omega-3s. 

The foundational ingredient in plant-based supplements is usually algae. Algae is the only plant source that provides you with both of these fatty acids, providing one of the best alternatives to fish oil.

Algae omega-3 supplements can provide you with multiple other benefits as well. Taking a supplement can help ensure that you receive a healthy balance of other nutrients, like omega-3s and omega-6s.

Choosing an algae omega-3 supplement also allows you to monitor and control your intake of omega-3s more effectively, unlike with fish oil, where you have to be careful not to take too much or too little. 

Supplements can also be designed to increase absorption of the nutrients by pairing additional nutrients together, whereas taking fish oil by itself for the sake of the EPA and DHA may not be as effective.

Leave Fish Oil Behind

Sure, fish oil is one of the most common sources of omega-3 fatty acids, but you no longer have to tolerate the side effects of this supplement just to receive the nutrients, especially if there are better alternatives. Fortunately, iwi life omega-3 provides your needed daily intake of omega-3 fatty acids without the side effects and inconvenience of fish oil. iwi life omega-3 is an algae-based supplement that offers both DHA and EPA fatty acids, providing you with the nourishment you need.

iwi life is proud to be at the front of the movement to find alternatives to fish oil to support individual health and wellness while choosing sustainable options for the health of the environment. See how iwi life lives out this commitment with all of our plant-based products by checking out our complete collection of plant-based supplements. We strive to provide you with the best nutrients possible for your own health, and the health of the planet.


Alternative Sources of Omega-3 Fats: Can We Find a Sustainable Substitute for Fish? | National Library of Medicine

Fish oil, cod liver Nutrition Facts & Calories | Nutrition Data

Omega-3 fatty acids and blood pressure

Vitamin A (Retinol) Information | Mount Sinai - New York

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