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Fish oil is a popular dietary supplement because of its powerful active component: omega-3 fatty acids. In this post, we'll answer the question of 'how long does it take fish oil to get out of your system?' by discussing the metabolization, processing, and elimination of omega-3s, which will help you understand how much you should be consuming
Omega-3s are important healthy fats that play supportive roles in cells throughout your entire body. Two omega-3s in particular, EPA and DHA, are beneficial for supporting a wide range of important systems in your body, like your heart, brain, eyes, and skin.*
Overview of fish oil and omega-3 absorption
When you take fish oil or eat fish (or any other food containing omega-3s), it goes through a series of biological processes to break it down into a form your cells can use. In other words, the foods and supplements you intake are digested and metabolized.
The main steps of omega-3 fatty acid metabolism include ingestion, digestion, absorption, cell utilization, and eventual elimination.
Ingestion
Your body doesn't make omega-3s on its own; instead, you must eat or take them as a supplement.
DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) are most commonly found in fatty, cold-water fish like salmon, tuna, and mackerel. You can also get these omega-3s from fish oil pills, which are made from the fat of these fish, or algae oil pills, which are made from microalgae.
Another kind of omega-3 fatty acid, ALA (alpha-linolenic acid), can be found in plant-based foods and supplements like chia seeds, flaxseeds, and walnuts. However, ALA must be converted into DHA and EPA for your cells to use them, which can decrease their overall efficacy.
Digestion
After you eat the omega-3 fatty acid source of your choice, it then starts its journey through your digestive system from your mouth and esophagus to your stomach, where the food is physically broken down. Enzymes called lipase also work in the stomach to break fatty acids into smaller components. They then travel further to your small intestines, where various components work together to metabolize those omega-3 fatty acids into smaller components for your cells to use.
For example, your liver produces bile, which helps break up those fatty acids to make it easier for you to metabolize. Then, more lipase acts on those fatty acids and breaks them into smaller molecules called fatty acids and glycerol.
Absorption into the bloodstream
After your digestive system successfully breaks down the omega-3s into smaller molecules, they must be delivered to cells throughout your body.
Most nutrients need to be processed by the liver during this stage, which further breaks them down and delivers them to the bloodstream. The bloodstream then carries them to different cells.
However, omega-3s first enter the lymphatic system, where they are packed into a form called chylomicrons. These large fatty particles then carry omega-3s through your lymphatic system before it eventually reaches your bloodstream. This allows omega-3s to be delivered to more tissues and cells before being further broken down by the liver.
Utilization by cells
After they are broken down and metabolized, omega-3s are then delivered to your cells, where they can do their jobs!
Omega-3 fatty acids play several important roles in your body once they are delivered to your cells via the bloodstream. For example, they are necessary to build the structure of your cell membranes. They also regulate cell function, boost your heart health, give your body anti-inflammatory support, and may even support your immune system!*
It generally takes about four hours for omega-3s to reach this point after ingestion, although it can vary based on several factors we will cover shortly.
Elimination
Finally, the omega-3 fatty acids that aren't used or stored are broken down through processes like oxidation. They are eventually eliminated as waste via your digestive system.
Factors affecting omega-3 absorption and metabolism
Age
Your digestive system undergoes some natural changes as you grow older. For example, your stomach tends to produce fewer stomach acids and enzymes that help break down your nutrients into smaller components.
As a result, your body's ability to digest and metabolize omega-3s may also slow down as you age. However, some evidence suggests that increasing your omega-3 intake as you age is essential since it may play anti-aging roles for your heart, brain, immune system, and bone health.*
Metabolism
Your metabolism is the rate at which your body breaks down food, absorbs its nutrients, and gets rid of waste afterward. Your metabolism is based on factors like age, general health, body composition, and genetics. Many of these factors can't be changed, but some research suggests that you may be able to increase your basal metabolic rate by exercising and increasing your muscle mass.
Diet
How you eat your omega-3 fatty acids can also play a big role in how quickly your body can digest and absorb those nutrients.
For example, choosing omega-3 sources that only have ALA can decrease your body's total intake of omega-3s since it first has to convert ALA into DHA and EPA. If you choose sources already rich in DHA and EPA, like fish oil and algae oil, you can essentially "skip" this step and get more of the omega-3s that your body 3needs. Studies have shown that some omega-3s from plant sources like nut and seed oils were not converted to DHA at all, while algae oil supplementation led to more significant increases in DHA levels in the blood.
Additionally, how you cook and prepare your omega-3s might also affect their bioavailability. For example, cooking foods under high heat (like frying) can sometimes degrade the omega-3 fatty acids.
Finally, other nutrients you eat alongside your omega-3s can also change how quickly they are absorbed and metabolized. For example, dietary fiber is thought to slow down your body’s rate of digestion, which can affect how quickly your body metabolizes dietary fats and omega-3s. Other research has found that getting an adequate level of Vitamin E is also important since it can help protect your body’s DHA sources from degradation.
Other dietary fats
Similarly, pairing your omega-3s with other dietary fats can also affect the rate at which they are absorbed. Evidence suggests that taking your omega-3 supplement along with another kind of fat can increase its bioavailability — in other words, your body will be able to use more of those essential omega-3 fatty acids!
Therefore, you should aim to take your omega-3 fatty acids with other healthy dietary fats like olive oil, plant-based fats, or lean protein sources to increase your absorption.
Overall health
Finally, your general health can also affect the rate you absorb omega-3s and other important nutrients.
For example, if you are deficient in omega-3 fatty acids, your body will likely use more of it more quickly to make up the difference.
Your gut health can also play a role. Some gastrointestinal disorders like inflammatory bowel disease (IBD) or general fat malabsorption might limit your body's ability to metabolize and/or absorb nutrients, including omega-3s.
How long does it take to get fish oil out of your system?
In general, the omega-3s that you eat take a couple of hours to reach your bloodstream. Within days of consistent omega-3 fatty acid consumption, you can see measurable changes in the amount of omega-3s present in your cells. It then takes several days to a week to be eliminated from your system.
However, remember that this is a general timeline and can vary based on the factors mentioned above.
It's also important to note that your body does store omega-3s when you are consistently eating enough of it. This is a good reason to make sure your diet has plenty of omega-3s and to supplement with a fish oil or algae oil pill if not. When you take omega-3 supplements or eat foods with omega-3s, those essential nutrients can build up in your system. It can also take several weeks or months to see changes if you take them for a specific health benefit.
Frequently Asked Questions
Can you take too much fish oil?
While getting plenty of omega-3s every day is a good idea, there is a limit. Because omega-3 fatty acids may have anti-inflammatory effects*, taking too much omega-3s may lead to a suppressed immune system, compromising your body's ability to fight infection. Additionally, EPA lowers your blood’s ability to clot, which may lead to increased bleeding.
In general, you should aim to get 1.6 grams (for males) or 1.1 grams (for females) of omega-3s per day based on the Dietary Reference Intake by the National Academy of Medicine. You may need to take more if you are currently pregnant or breastfeeding.
The right amount for you may also vary based on your current health and whether or not you're trying to achieve a specific health benefit. Talk to your doctor to determine the correct dosage for your needs.
What are some signs that I am not getting enough fish oil?
Omega-3 inadequacies may be associated with increased risks of chronic diseases like coronary heart disease.* However, a true omega-3 deficiency is very rare. If you do have a full omega-3 deficiency, it might present itself in symptoms like rough, irritated, or inflamed skin, dry eyes, and/or joint pain.
Does fish oil have side effects?
The most common side effect of using fish oil is indigestion and/or “fish burps,” an unpleasant taste or smell of fish after taking the fish oil capsule. Long-term overuse of fish oil may be linked to issues with suppressed immune systems and increased bleeding (see above).
How can you ensure optimal absorption of fish oil?
Factors affecting your body's ability to absorb fish oil aren't easily controlled, like genetics, metabolism, and age. However, you can increase your absorption of fish oil by choosing high-quality sources, pairing your food or supplementation with other dietary fats, and avoiding taking it on an empty stomach.
What time of day should I take fish oil?
There's no "right" time to take fish oil or other omega-3 supplements, which is ultimately up to your preferences and routine. However, it's best to take your omega-3s around the same time every day and to pair it with some food with dietary fat to help increase your body's absorption. For example, you might prefer to take your omega-3s in the morning along with your avocado toast to help you stay consistent.
What are some alternative sources of omega-3 fatty acids if I don’t like or can’t tolerate fish oil?
If you do not want to use fish oil but want to add more omega-3s into your diet, microalgae oil pills are an excellent alternative to fish oil. Microalgae oil contains both EPA and DHA. It is also plant-based and produced more sustainably than classic fish oil.
Conclusion
Omega-3 fatty acids are an essential nutrient that is absorbed and used relatively quickly once ingested. To capitalize on their health-boosting properties, you should eat them consistently and choose high-quality omega-3 sources with EPA and DHA.
