Fish Oil Side Effects

by Dr. Leo Galland


Fish Oil Side Effects

Fish oils are a major source of omega-3 fats which have many health benefits.  However there are numerous side effects of fish oil supplements. Breaking out a bottle of fish oil could lead to breaking out in acne.


Some fish oil side effects include:


  • Fish oils decrease the tendency of blood to clot. This action can cause side effects like bruising or prolonged bleeding from a cut. Some studies have found that this side effect is more likely to occur in people who take aspirin in addition to fish oils. Fish oil supplements should usually be discontinued about 2 weeks before elective surgery.



  • Fish oils can cause diarrhea, which is the most commonly reported side effect in clinical research studies. Diarrhea may necessitate lowering the dose of fish oil. Taking fish oils with food or with calcium pills (but not magnesium) may decrease this side effect.


  • People may burp fish oil, or experience heartburn or reflux, a potentially damaging side effect. The side effect of burping fish oil may be reduced by using a delayed-release or enteric coated fish oil and by taking the capsules on an empty stomach with a large glass of water and a capsule of digestive enzymes. 



  • Fish oils may cause acne. This is more likely in people with oily skin. Acne as a side effect may be prevented by also taking zinc tablets (about 15 to 30 milligrams per day) and by avoiding supplements that contain vitamin B12. Acne is a potential side effect of vitamin B12.


  • Fish oils may increase the need for omega-6 fats, especially those found in supplements like evening primrose oil, borage oil or black currant seed oil. Because the omega-3 fats found in fish oil compete with omega-6 fats for use by the cells, it may actually induce a relative deficiency of omega-6 fats by taking fish oils. Signs that this side effect is happening are dry skin or hair, hair loss, brittle nails or menstrual irregularities, that start or get worse when taking fish oil.


  • Fish oils may suppress the immune system, rather than strengthen it. This side effect can contribute to having more infections while taking fish oils. Reduction in the amount of fish oils used or taking antioxidant supplements could help.



14 thoughts on “Fish Oil Side Effects

  1. JL

    Thanks for confirming my suspicion on the link between fish oil and acne! I experienced this. I’m mid-50’s and a few months ago suddenly starting getting constant acne outbreaks. I’ve always had oily skin, but haven’t had anything but the occasional outbreak for years. I thought back to what had changed, and realized I’d started taking fish oil capsules. Within a day or two of stopping the fish oil, the outbreaks stopped.

  2. John

    Thank you Dr. Galland. I have recently started taking fish oil and it seems that it gave me more breakouts than usual, plus whiteheads that I never get even on my eyelids. I already take a daily multivitamin with 15mg of zinc in it, my skin is not extremely oily but the fish oil did make it worse.

  3. Sandra Jackson

    I think I have found the answer to my cramping in legs toes and locking thumbs. I gave out of fish oil pills and have not gotten them refilled and symptons have gone away. I also started loosing my hair and it has become dry also skin is very dry. I am on a lot of meds for my heart but I think this is the culprit. I am going to stay off and just see if I get better. I had been taking them a long time. I was not able to take statins for cholesterol so I got the fish pills. I had severe cramps in calves of leg and thumb would lock down. I had my potassium checked and it was fine. I am almost sure this is the cause. I am glad i found this site and started checking into this…. Thanks

  4. debbie

    i have experinced side effects since taking fish oil bt take it for depression so if i stop taking it can you advise an alternative,thank you

  5. sam

    i just started taking omega-3 1 week ago–i broke out with whiteheads on my nose and surrounding area. never in my life have i had so many..and they don’t heal well either. will stop taking pills today..let’s see if they go away.

  6. Shawn

    I recently added a triple strenght fish oil with phytosterols and my back is loaded with acne. I take zinc as part of my multi vitamin with no help. At 45 it is a bit embarrassing.

  7. kelly

    i found answer for my menstruation problem now. i never had this kinda problem before i start to take omega 3 fish oil. my menstruation is delayed n not in normal flow.. i am alrdy lacking hemoglobin in my blood cells.. n i did not expect fish oil will worsen my cycle this bad. disappointed.

  8. mica

    When I started taking fish oil pills, within 5 days I developed very severe cystic acne on my cheeks which used to be clear and oil-free (no effect on t-zone which is oily and acne-prone, whatsoever). Unfortunately I didn’t put the two together until a month had passed. Now its been a year, and cheeks have healed a lot, but I still have hyper-pigmentation, small pimples, and get a cyst or two a month, and my cycle’s not quite back to normal. I wonder how much longer it will take for my cycle and cheeks to get back to normal and how/why this reaction occurred.

  9. aileen

    Oh my God, this must be the reason why I have acne breakouts like I never ever had in my whole life. I am going to stop taking fish oil and I hope it works for me because until now I could not figure out why I have these breakouts. One site recommends to avoid stress but seeing my face with acne all over adds to the stress.

  10. Emi

    I think that taking Carlson fish oil just for 5 days 3 teaspoon made me the cyst inflamed acne I just got 5 days ago. Now how much time I have to wait to return to normality or how can you get ride of the fish you took???

  11. Gigi

    took fish oil (1000mg x 2 per day) for 6 months and my hair shedding like cat for about 5 months plus. stop for few days already hoping hair loss be better in future. anybody experience this kind of condition before? possible to get rid of the fish oil in the body?

  12. Gcf

    I don’t really have and increase in acne, but get boils??? So I take Flax Seed oil. Even 1 fish oil after taking Flax for months will cause me to get a boil or 2…

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