difference between fish oil and krill oil

Fish Oil vs Krill Oil for Health & Fitness (Backed by Science)

November 19, 2020

Whether its fish oil, krill oil, cod liver oil, or flaxseed oil, fitness enthusiasts, bodybuilders, athletes and health-conscious consumers have been enjoying the benefits of omega-3 supplements for a long time now. With any amount of research, you can discern that getting adequate amounts of omega-3s is very important for health and fitness. The plethora of scientific studies will provide you plenty of proof.

Since you are reading this, you are considering to take an omega-3 supplement, or you potentially want to switch from the traditional omega-3 supplement, fish oil, to the newer cardinal in the omega-3 supplement line up, krill oil. With that, we are here to tell you everything you need to know about fish oil and krill oil. We will be comparing krill oil vs fish oil so you can make an informed choice on your next omega-3 supplement purchase.

So, let’s find out, which is better for health and fitness, fish oil or krill oil?

All of the information below is backed by science, and we have provided links to studies to confirm many of our statements.

**We provided some links below to our favorite supplement provider where we will will receive a small commission for sales generated. These products we've tried and used ourselves, we hope you enjoy these products as much as we do.**

fish oil vs krill oil

To start, we want to go over some important points, like what exactly is fish oil and krill oil, what are omega-3s, why are they important and what are the benefits for health and fitness. Afterward, we will discuss the main topic of today, fish oil versus krill oil…

What is Fish Oil?

Fish oil has been the go-to source for omega-3s for a long time. The omega-3 fatty acid is extracted from the tissue of fatty, oily fish, such as salmon, tuna, halibut, anchovies, mackerel, sardines, and herring. The end product is a golden color and it comes in the form of liquid, capsules or pills.

which is better fish oil or krill oil

What is Krill Oil?

Krill oil, as the name implies, comes from the small crustacean krill, which looks similar to shrimp, but they are a lot smaller. Krill live deep down in the ocean where it is extremely cold. They can be found in all of the world’s five oceans. In the Southern Ocean, “Antarctic krill” make up an estimated biomass of approximately 379M tons, which makes it the species with the largest total biomass. The point is, there is plenty of krill to go around.

Like fish oil, krill oil is rich in omega-3 fatty acids.

Krill oil only comes in capsule form.

what is krill oil

What are Omega-3s?

There are three types of fatty acids, all of which are long chains of carbon. They are classified as saturated, monounsaturated and polyunsaturated. Polyunsaturated fats are made up of omega-3s (alpha-linolenic acid) and omega-6s (linoleic acid). Omega-3s and Omega 6s are referred to as “essential fatty acids”.

Our bodies require both essential fatty acids (omega-3s and omega-6s) for optimal health. However, we can’t make these essential fatty acids naturally in our body. This is why they are “essential”. The “essential” means we need to consume them in our diet (by food or supplementation).

Omega-3s: What is EPA and DHA?

When you consume omega-3, the body converts them into DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). Both DHA and EPA (essential fatty acids) take on very important roles for your health.

EPAs are mainly working on heart health, and DHAs are essential for brain and eye development and functioning as well as reducing inflammatory responses and improving heart health.

Should I Take an Omega-3 Supplement?

krill oil versus fish oil

The vast majority of people, especially Americans, consume way too few omega-3 fats and way too much omega-6 fats. Most Americans take in 10 times more omega-6s than omega-3s. That’s a 10 to 1 ratio. The ideal ratio would be 2 to 1 or even 1 to 1 according to most health experts. The main reason for this over consumption of omega-6s is due to all the vegetable oils, such as corn and sunflower oil, that food production companies and restaurants use.

This is a big problem for our health. If you consume way too many omega-6s, it can trigger inflammation, sensitivity to pain, and thickening of blood.

Many studies show that by increasing your omega-3 fats and decreasing your omega-6 fats, you can reduce your likelihood of inflammatory diseases, as well as decrease your risk of developing heart diseases.

To do this, you can either eat fish (and other foods rich in omega-3s) or consume omega-3s through supplementation.

The two best supplements for omega-3s are fish oil and krill oil because they are the most rich in the essential fatty acids EPA and DHA.

If you are able to buy good quality fish, a minimum of 8 ounces of omega-3 rich fish per week is ideal. You could do two servings of 4 ounces spread out through the week.

Omega-3 rich fish include salmon, mackerel, tuna, herring, sardines, and many other seafoods. Good plant based alternatives for omega-3s are flaxseed, chia seeds, and walnuts. However, it is important to note that the omega-3s found in fish and seafood (as well as fish oil and krill oil) have greater health benefits than plant-based omega 3s.

Now, there are two issues with eating fish. First, it can be expensive and hard to maintain consistency. Second, and more importantly, a lot of our fish supply is heavily contaminated with pollutants, heavy metals, PCBs, and other toxins. If you are eating this on a weekly basis, you can understand just how bad this could be for your health.

If you can’t be sure of the source of your food, or you simply want an easy way to consume your omega-3s in the right amounts, supplementation is a smart way, so long as you are buying quality product.

should i take fish oil or krill oil

How much Omega 3 should I consume?

If you are consuming your omega-3s just by food, have two servings of fish per week (or 8 ounces in total per week). This is an ideal amount for a healthy adult.

For those who want to take supplements for their omega-3s, you should take around 250-500mg per day. This is a combined amount that includes both EPA and DHA.

For fish oil, you’d be on the higher end due to the bioavailability (we will get into this further below). Krill oil around 300mg is perfect as it has better bioavailability.

In any case, a good supplement company will have the perfect dosage on their labels. Just follow that and you will be good to go. One dose a day is enough.

Note: Due to the importance of essential fatty acids in the development of babies, pregnant women should take a higher amount during pregnancy. Around 650mg is ideal.

Is it good to take omega 3 supplements everyday?

Yes, it is good to take omega-3 supplements everyday. There is nothing to worry about. Safe levels are as high as 5,000mg, so even if you eat fish on the day you take the supplements, you have nothing to worry about. Some experts actually recommend you take up to 1,000mg per day for optimal health, so it would really be hard to overdo it unless you take a huge dose everyday.

If you were, by some ridiculous chance, to consistently over-consume omega-3s, it could take a toll on your health and cause side effects like high blood sugar and increased risk of bleeding. Again, this is very unlikely as you’d have to purposely take too much omega-3s to get to that point. But the risk should not be overlooked.


importance of omega 3 essential fatty acids

Just to reiterate, most American diets are much higher in Omega-6s, and this is bad as you want the ratio to be nearly even. A good ratio is important for your overall health. This is why supplementation of omega-3s is so commonly recommended.

The best way to create a healthy essential fatty acid balance is to try and decrease your omega-6s and increase your omega-3 intake.

If you have a good ratio of omega-3s and omega-6s, you will be optimizing many bodily processes.

A healthy balance of EFAs are critical for:

  • Development and function of the nervous system and brain
  • Healthy cell membrane formation
  • Production of hormones
  • Blood pressure regulation
  • Liver function
  • Immune health
  • Inflammatory responses
  • Thyroid and adrenal activity
  • Blood clotting regulation (omega-3 reduces clotting, whereas omega-6 promotes blood clot formation, making the balance between the two vital).
  • Supports the integumentary system (skin, hair, nails)
  • Breakdown and transport of cholesterol

Conversely, if you have an imbalance of omega-3s and omega-6s, studies show it may cause serious health conditions like heart attacks, cancer, Alzheimer's disease, asthma, depression, arthritis, insulin resistance, accelerated aging, stroke, obesity, diabetes, ADHD, and the list goes on. This is not to scare you but to put you on a healthy path.

Health Benefits of Fish Oil & Krill Oil:

Both fish oil and krill oil are touted for their ability to boost aspects of your health because they are rich in omega-3s. Supplementing fish oil or krill oil is said to help lower blood pressure, slow down the development of plaque in the arteries, reduce triglycerides (reduces risk of stroke, heart attach and other heart diseases and abnormalities), fight off depression and anxiety (by allowing serotonin to move more easily between cells), the immune system operate properly, lower inflammation levels, as well as promote joint, bone and even eye health.

Many of these same benefits of fish oil and krill oil can be related to sports and fitness. Let us explain more for the purpose of bodybuilding and athletic performance…


is krill oil better than fish oil for athletes and bodybuilders

The main fitness benefits of consuming omega-3 fatty acids in the form of fish oil or krill oil are reduction of joint pain, quicker muscle recovery, fat loss, slows down muscle loss during longer periods of not training (typically due to injuries in sports), and improvements in cardiovascular capacity and overall workout performance.

Let’s take a look at each point individually…


Both high levels of omega-6s (i.e. imbalance in the ratio of EFAs) and high intensity workouts are known to impact immune function and inflammation. With the combination of the two, you are especially susceptible to prolonged recovery time and even illness if you do rigorous workouts with not enough rest days.

Taking an omega-3 supplement daily will help you keep inflammation in check while also augmenting your blood flow to muscles and joints. This has a very positive effect on muscle soreness, tissue repair, joint health and immune response.

This is one of many studies that shows omega-3s active ingredients, EPA and DHA, inhibit the development of DOMS and prevent temporary muscle strength loss.

This study by the Journal of Sports Science Medicine gave 27 women 3,000mg of DHA and the report found 23% less soreness than the placebo group.

Research shows omega-3 supplementation reduces the severity of DOMS (delayed-onset muscle soreness) that results from eccentric strength exercise.

Krill oil study shows an increase in immune responses 3 hours after a maximal exercise test. 


When omega-3 levels are increased, it enhances your muscle building response to insulin and amino acids, both of which are released during workouts. It also lowers triglycerides. This improves fat burning and inhibits fat storage.

New studies are also showing omega-3 fatty acids prime muscle cells for protein synthesis. As such, you can get more from your nutrition, leading to better muscle growth.

The Journal of Applied Physiology, Nutrition, and Metabolism reports that the healthy adults in the study who took 3,000mg of fish oil per day for 12 weeks had their metabolic rate increased by an average of 5.3%. This meant they were burning more calories when resting than other groups who were not supplementing with fish oil.

This study of 44 men and women who received either 4 grams of fish oil (1600 mg EPA and 800 mg DHA) or 4 grams of safflower oil showed 6 weeks of supplementation with fish oil significantly increased lean mass and decreased fat mass. 

Here’s a study that found krill oil’s metabolic effect is essentially similar to fish oil but required a lower dose of EPA and DHA.

There are many more studies showing positive results on both fat loss and muscle growth when supplementing omega-3 fatty acids. These are but a few.


We all know that when it comes time to cut weight and lose fat, a certain amount of muscle degradation occurs. Supplementing with omega 3 is said to help on this front as well. It is shown to limit muscle loss during these cutting phases.

The same thing occurs when you take a break from the gym. If you experience an injury, as many athletes occasionally do, taking omega-3s during extended periods of rest can slow down muscle loss and keep your bones strong.

This slowing down of muscle loss occurs for the same reason omega-3s promote muscle growth when working out consistently. The active ingredients, EPA and DHA, prime your body for protein synthesis.

This is a very interesting study by McMaster University in Ontario, Canada. It took 20 healthy women and divided them into two groups. One group took 5,000mg of an omega 3 supplement and the other a placebo. The study was conducted over 4 weeks, and all of the women had to wear immobilizing leg braces for the first two weeks. The women had the same exact diet, including protein levels based on their bodyweight. In the end, the women taking fish oil supplements had significantly less muscle loss during the two weeks of immobilization and were able to full recovery muscle volume after the final two weeks of the study.


Fish oil is now thought to reduce heart rate and oxygen consumption and demand during exercise. Moreover, it does it without any decrease in performance.

The study evaluated 16 cyclist. Half took 8 grams of fish oil per day and the other took a placebo. The cyclist who took fish oil had decreased heart rate and a decrease in the amount of oxygen their body burned every minute.

As you can imagine, for a competitive athlete like runners and cyclists, that is big news. If you body requires less oxygen than your competitor, it will cost you less energy to finish the marathon.

The same thing applies to all sports, and even strenuous workouts, like Crossfitters undergo during and in preparation for competition.


When it comes to certain sports, the brain is often as important as the body. Omega-3s are highly coveted for their cognitive support ability. They improve reaction time.

This study shows how DHA rich omega-3s improved complex reaction time in 24 female soccer players. 

Your brain is 60% fat, and 15% of that should be omega-3s DHA. So, you can see the importance of getting an adequate amount of omega-3s.


With all of the studies conducted, it is pretty clear that omega-3s (EPA and DHA) have very positive effects on overall sports and fitness performance. They reduce soreness, increase recovery time, reduce loss of muscle strength and range of motion after exercise, increase metabolic rates, and promote and maintain muscle strength and growth. They even help cognitive functions so athletes can keep quick reaction times when fatigued.

The opposite is all true if your omega 6s and 3s are out of balance. High omega 6s ratios will cause inflammation, prolonging recovery and soreness.

If you want to improve your athletic performance during game time or in the gym, getting adequate amounts of omega-3s is vital. Supplementation just makes life a whole lot easier…

Now, to the questions you came here for…

is fish oil or krill oil better for bodybuilding


Krill oil and fish oil are similar in that they are both excellent sources for the essential fatty acids, Omega-3 EPA and DHA.

However, there are some key differences in the two supplements. Let’s discuss the main differences.


Fish oil contains more EPA and DHA omega-3s than krill oil, yet krill oil has a superior absorption rate, meaning total omega-3 consumption is pretty similar, even if you take less krill oil.

Additionally, both krill oil and fish oil contain more than omega 3 fatty acid DHA and EPA. Fish oil usually contains vitamin A and D. Krill oil does as well, however, in higher amounts, and it also contains vitamin E.

Where krill oil really stands out in terms of nutrients is that it contains astaxanthin and choline. Fish oil does not.

Astaxanthin is an antioxidant that helps protect against UV light, as well as increase the Oxygen Radical Absorbance Capacity potency (a way to measure the “total antioxidant capacity”) of krill oil by up to 48 times that of fish oil. Astaxanthin is also what makes krill oil have a much longer shelf life. It reduces oxidation, which lowers the risk of rancidity.

As for choline, it is a macronutrient that naturally occurs in krill oil. Our bodies can produce small amounts, but we rely on food to meet the levels we need. Choline is critical for our well being because it is required during essential processes in our cell membrane, along with its function and signaling capacity. What’s more, like omega-3s, it has an impact on our cardiovascular health and brain and liver function. When choline levels drop during endurance exercises or events, it can negatively impact performance, so it is important that levels are adequate. Supplementation from krill oil has proven to be very effective for keeping choline levels up for rigorous endurance training. Choline also plays a big role in producing a neurotransmitter that is active in our neural networks that relate to memory and muscle function.

If choline levels are low, we have an increased risk of fatty liver, heart disease and memory interference.

All in all, both fish oil and krill oil are great for omega-3s, but krill oil does reign supreme due to it having astaxanthin and choline.


The main difference in the omega-3 fats found in fish oil is they come in the triglyceride form, whereas in krill oil they’re in the phospholipid form.

Our fat cells and our cell walls are also in the phospholipid form. This means the phospholipids of krill oil can go directly into our bloodstream. They are water-soluble and our body immediately recognizes and absorbs them. This makes krill oil significantly easier and quicker to absorb.

Since fatty acids in fish oil naturally occur in the triglyceride form, they have to processed by our liver before the body can absorb them.

When we look at absorption time, krill oil takes around 3 hours to completely absorb. Fish oil takes 48-72 hours. For fitness enthusiasts and athletes who want to reap the benefits of omega-3s, such as quick recovery, protein synthesis, and increased metabolic rate, you can see why faster absorption is better.

So, while there are more EPA and DHA in fish oil, the EPA and DHA in krill oil is easier to absorb and they are more bioavailable (around 68% more bioavailable than fish oil), allowing you to get more out of less. Moreover, this makes krill oil easier on your digestive system. You can take fewer supplements and get the same results in a fraction of the time.

This study shows that EPA and DHA concentrations increase significantly more with krill oil comparing to fish oil.


This study shows that HDL cholesterol (good cholesterol) improved ten times more when comparing krill oil to fish oil. The same study also showed that LDL levels (bad cholesterol), decreased by 32% with krill oil and only 2% with fish oil. 

What’s even more interesting about the above study is that the krill oil was given in lower doses than the fish oil. This goes back to our point about krill oils superior bioavailability.


Fish oil in liquid form is perishable and becomes rancid quite quickly. It is important to keep it stored in the refrigerator once opened. Cool temperatures slows down oxidation. If your fish oil has a fishy taste, that is due to oxidation and it shouldn’t be consumed as it can potentially do damage to your organs according to some animal studies. Just like fresh seafood, your fish oil should have no fishy taste or smell.

As for capsules, they have a much longer shelf life of around 24 months. Again, if it has that fishy or rancid smell, you should not take them.

The manufacturing, transportation, and storage processes of fish oil can cause rancidity. Unless the fish oil was cold processed, transported in cooled trucks, and then stored in the refrigerated section of the store, there is a chance it is rancid. Again, buying quality fish oil from a good source is very important, as rancid fish oil is not healthy.

Fish oil can even oxidize and become rancid in your body because of how long it takes to absorb (48-72 hours). Because of this, it is important that you take or eat foods that have antioxidants along with your fish oil. This will negate any negative effects that fish oil may cause due to oxidation.

With krill oil supplementation, it absorbs in the body within 2-3 hours. Moreover, thanks to it containing astaxanthin, you have 48 times the antioxidants potency compared to traditional fish oil.


Krill oil is more pricey than fish oil.

Why is krill oil more expensive?

Most fish can yield much more fat. For example, sardines and anchovies yield around 80% fat. Krill oil, on the other hand, yields around 5% fat. Because of this, you have an increase in the time of decomposition. Krill oil will last longer once it is in supplement form, but before it is processed, it needs to be done quickly to prevent oxidation. With that, manufacturers need to keep the krill alive in water tanks or frozen. This significantly increases manufacturing costs.

Overall, fish oil is much easier to produce.


If you aren’t aware, overfishing is a serious ecological danger. The UN stated that 17% of fish stocks globally are overexploited, 52% are full exploited, and 7% are completely depleted. With how popular fatty fish are, they are the most exploited of all fish.

Conversely, krill fishing is strictly regulated by the CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources). CCAMLR reproved the yearly catch of krill is less than 0.3% of the unexploited krill biomass. In other words, they are catching way below dangerous ecological levels. This makes krill oil a lot more sustainable. Also, remember, krill has the largest total biomass of any animal species on earth.  

krill oil vs fish oil for cholesterol


Krill oil is still relatively new to the supplement market. Before ten years ago, no one was talking about it. As such, there are many more studies on fish oil than krill oil. That said, the studies on krill oil show it is very promising and even better than fish oil in many regards. Yet, more studies will be coming to prove if all the finding, such as better absorption and better heart health benefits, are true. Krill oil may very well be the king of omega-3 supplements someday, but for now, fish oil is still the most popular choice.

In any case, it is safe to say you can’t go wrong with either. Both are fantastic sources for EPA and DHA and they both have a lot of research done on them (although fish oil more).

After reading everything in this article, you should have a good idea of what you want to choose.

We would say if you want a supplement rich in EPA and DHA at a good price, fish oil is the best bet.

However, if you don’t mind spending a little more for a possible greater health & fitness benefit, give krill oil a try.

You can also test both and see what you like best. Give fish oil a try for a month and then give krill oil a try, or vice versa.

One thing we can be sure of is that everyone needs to be consuming complete essential fatty acids, specifically omega-3s. To improve your health and enhance your fitness, you need to get your ratio of omega-6 fats equal with your omega-3 fats. Since most of us can’t rely on eating good fish for essential fatty acids, omega-3 supplements are a must. Whether you decide on fish oil or krill oil, both are good choices, so don’t stress it. Take the information above and make your own informed choice. Just take both in the right doses and you will be perfectly fine and on your way to being healthier.

Choose a good supplement company!

More importantly than whether you choose fish oil or krill oil, you need to choose a good quality supplement. Just like fish oil, krill oil supplements can be bad. If the krill oil was sourced from pollutant-rich ocean areas, then that is no good. The same goes for fish oil, on top of the rancidity factor.

The easiest way to know if a supplement is good is to buy from a trusted source with many good reviews.

** This is a an affiliate ad above that we will receive a small commission on any purchase you make. We only link to sites like this that we use ourselves to purchase our supplements.***


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