Side effects of Omega 3: You should know these

Nebenwirkungen von Omega 3: Diese solltest du kennen

Omega 3 is often touted as the wonder drug in nutrition. It is said to have a variety of positive effects on the body, such as supporting the immune system and protecting against cardiovascular disease. The anti-inflammatory properties are said to even help with skin diseases such as acne or neurodermatitis.

Omega 3 side effects are rarely mentioned. Nevertheless, undesired symptoms can occur with the excessive intake of omega 3 in the form of supplements. In this article we will explain all possible side effects of omega 3 to you. We will also explain how you can avoid side effects and thus benefit optimally from the health benefits of fatty acids.

the essentials in brief

  • Omega-3 fatty acids are said to have many health benefits. Therefore, they are particularly common in the form of dietary supplements such as fish oil. Capsules or algae oil taken.
  • Although the fatty acids are generally considered to be health-promoting, side effects can occur, especially when ingested. This mainly occurs when the dosage is too high.
  • People who take blood thinners, people with low blood pressure or diabetics should be especially careful when taking omega 3. Healthy people can usually consume Omega 3 in the correct dose without hesitation.

Omega 3 Side Effects: What You Should Know

Although omega 3 has many health benefits and is essential for the human body, there can also be side effects from taking omega 3. In the following sections we will inform you about the current study situation on the subject of omega 3 side effects and answer all important questions on the subject.

What is Omega 3 and how does it work?

Omega-3 acids are polyunsaturated fatty acids. They occur naturally in fish, flaxseed oil and nuts. Since the western diet often contains too little omega 3 and too much omega 6, it is often recommended to take dietary supplements such as fish oil capsules or algae oil .

Omega 3 capsules

Omega 3 is contained in natural foods such as linseed oil or fish. However, it can also be supplemented with fish oil capsules, for example. (Image source: PublicDomainPictures / Pixabay)

Omega 3 has an anti-inflammatory effect and is said to support the immune and cardiovascular systems. In addition to the health benefits, Omega 3 is also said to have a positive effect on the appearance. Its anti-inflammatory properties can reduce skin imperfections, for example. (3)

What side effects does Omega 3 have?

Often only the benefits of omega 3 are talked about, although the fats can also cause side effects. Below we go into more detail about the individual side effects. Here is an overview:

  • Low blood pressure
  • Increased bleeding risk
  • indigestion/diarrhoea
  • overweight
  • high blood sugar

Healthy people usually do not experience any side effects with the correct dosage of omega 3. However, people with diabetes and low blood pressure should take extra care when taking omega 3 supplements. Even if you are already taking blood-thinning medication, you should discuss the additional intake of omega 3 with your doctor.

What side effects can occur with an omega 3 overdose?

In general, an overdose of omega 3 through diet is very unlikely. In the western world, it is generally more likely that too little omega 3 is consumed than too much. However, those who consume Omega 3 capsules in extremely high amounts increase their risk of side effects.

How does omega 3 affect blood pressure?

Omega-3 fatty acids have an antihypertensive effect. This is an advantage for people with high blood pressure and can reduce cardiovascular problems that can be attributed to high blood pressure. (6.7)

Omega 3 can lead to low blood pressure.

However, in people who already have low blood pressure, an antihypertensive effect can cause problems. If you experience symptoms of low blood pressure , stop taking omega 3 supplements and contact your doctor.

How does omega 3 affect blood clotting?

Omega 3 has a blood thinning effect. Therefore, omega 3 can lead to an increased tendency to bleeding and nosebleeds. If you are already taking blood thinners, you should consult your doctor before taking omega-3 supplements.

However, as a healthy person, the risk of bleeding is low with an appropriate dosage. A study examined the tendency to bleed during operations with increased omega 3 intake and found no difference to the control group. (9)

How does Omega 3 affect digestion?

Digestive problems often occur with high fat intake. Omega 3 can also cause digestive problems such as diarrhea and abdominal pain. These complaints are usually only to be expected with very high amounts. In general, a diet that is too high in fat can cause symptoms. (2)

Woman leans her head against the bed

Omega 3 can lead to digestive problems such as diarrhea. (Image Source: Sydney Sims / Unsplash)

Digestive discomfort after taking omega 3 supplements can usually be avoided by taking them with a meal. Try not to take fish oil capsules on an empty stomach and double check your dose. If you are already suffering from diarrhea, stop taking it until your digestion has calmed down. (4)

How does Omega 3 affect the skin?

Side effects related to the skin are not to be expected. In fact, omega 3 has mostly positive effects on the skin because it has an anti-inflammatory effect. For example, inflammation and skin impurities can be positively influenced. (5)

Itching is also not a side effect of Omega 3. On the contrary, Omega 3 can even have a positive effect on itching and skin diseases. Taking omega 3 during pregnancy can reduce the risk of the child developing the skin disease neurodermatitis. (10)

How does Omega 3 affect weight?

When considering the effect of omega 3 on body weight, it is important to consider an individual's overall fat intake. A higher intake of omega 3 fatty acids and a reduced intake of omega 6 fatty acids lowers the risk of obesity. The ratio in which we take in omega 3 and omega 6 acids is particularly important for the body. (1)

However, excess intake of omega 3 can lead to weight gain. This is because the healthy oil is fats. These have a higher number of calories than, for example, carbohydrates or proteins.

Calorie balance matters when it comes to losing weight.

Nevertheless, at the end of the day it always comes down to the total calorie balance. Substituting omega-3 oil for other fats in your diet is unlikely to have a negative impact on your weight.

However, if you take in high amounts of omega 3 in addition to your normal diet, you can more easily exceed your daily requirement and gain weight. However, people who are overweight should make sure to reduce their intake of omega 6 fatty acids.

How does omega 3 affect diabetics?

Taking high levels of omega 3 can lead to elevated blood sugar levels in diabetics. However, this is only the case at high doses. If you suffer from diabetes, it is advisable to pay particular attention to an appropriate dosage and to monitor your blood sugar levels conscientiously. (8th)

How can I avoid side effects when taking Omega 3?

Side effects with omega 3 usually only occur at high doses. If you stick to the dosage recommendations for fish oil capsules, algae oil and Co., you usually don't have to expect side effects. Nevertheless, it is best to take omega 3 supplements with a meal to avoid digestive problems.

side effect tips
indigestion Be careful not to overdose on omega 3 and take supplements with a meal. (4)
Low blood pressure If you already suffer from low blood pressure, you should only take dietary supplements with omega 3 after consulting your doctor. (6.7)
Increased bleeding risk If you take blood thinning medication, you should be careful when taking omega 3. (9)
overweight Make sure you have an adequate dosage of omega 3 and try to replace other fats in the diet with omega 3 acids instead of taking them in addition.
Elevated blood sugar If you suffer from diabetes, make sure you take the right dose and monitor your blood sugar carefully. (8th)

Overdosing is also unlikely when using linseed oil in the kitchen or consuming omega 3 from fish. If you already integrate enough omega 3 fatty acids into your diet, for example by eating fish regularly, you can do without an additional intake of omega 3 in the form of capsules.


Omega 3 fatty acids are essential for the body. Since most people in western countries consume too little omega 3 and too much omega 6, supplementation can make sense.

Nevertheless, omega 3 is not a miracle cure and taking it can be associated with side effects. People who are taking antihypertensive medication, people with low blood pressure and diabetics in particular should discuss taking fish oil capsules or algae oil with their doctor.


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  2. Rohr MW, Narasimhulu CA, Rudeski-Rohr TA, Parthasarathy S. Negative Effects of a High-Fat Diet on Intestinal Permeability: A Review. Adv Nutr. 2020 Jan 1;11(1):77-91. doi: 10.1093/advances/nmz061. PMID: 31268137; PMCID: PMC7442371. Source
  3. Shahidi F, Ambigaipalan P. Omega-3 Polyunsaturated Fatty Acids and Their Health Benefits. Annu Rev Food Sci Technol. 2018 Mar 25;9:345-381. doi: 10.1146/annurev-food-111317-095850. PMID: 29350557. Source
  4. Bradberry JC, Hilleman DE. Overview of omega-3 Fatty Acid therapies. P T. 2013 Nov;38(11):681-91. PMID: 24391388; PMCID: PMC3875260. Source
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  6. Colussi G, Catena C, Novello M, Bertin N, Sechi LA. Impact of omega-3 polyunsaturated fatty acids on vascular function and blood pressure: relevance for cardiovascular outcomes. Nutr Metab Cardiovasc Dis. 2017 Mar;27(3):191-200. doi: 10.1016/j.numecd.2016.07.011. Epub 2016 Jul 26. PMID: 27692558. Source
  7. LY Tao, YR Wang, YF Zhang, P Liu, XH Chen. Does omega-3 lower blood pressure?: A protocol for systematic review and meta-analysis. Medicine (Baltimore). 2020 Aug 28;99(35):e21955. doi: 10.1097/MD.0000000000021955. PMID: 32871944; PMCID: PMC7458235. Source
  8. Chen C, Yu X, Shao S. Effects of Omega-3 Fatty Acid Supplementation on Glucose Control and Lipid Levels in Type 2 Diabetes: A Meta-Analysis. PLoS One. 2015 Oct 2;10(10):e0139565. doi: 10.1371/journal.pone.0139565. PMID: 26431431; PMCID: PMC4591987. Source
  9. Begtrup KM, Krag AE, Hvas AM. No impact of fish oil supplements on bleeding risk: a systematic review. Dan Med J. 2017 May;64(5):A5366. PMID: 28552094. Source
  10. Makrides M, Gibson RA, McPhee AJ, Yelland L, Quinlivan J, Ryan P; DOMINO Investigative Team. Effect of DHA supplementation during pregnancy on maternal depression and neurodevelopment of young children: a randomized controlled trial. JAMA. 2010 Oct 20;304(15):1675-83. doi: 10.1001/jama.2010.1507. PMID: 20959577. Source
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