I suddenly began to experiencing horrible depression, anxiety, and insomnia. Talked to my doctor, therapist, and even a psychiatrist. Blamed the side effects on recently prescribed medication I only took for 2 days but even after I stopped they didn't go away.. A week later and I'm sitting here thinking any am I still feeling "off"... Then it hit me... A couple weeks ago, I decided to replace my fish oil with krill oil after hearing about all of the positive effects. BAD IDEA!! These are all of the side effects I ended up with: Agitation: In some cases, the krill oil supplementation may elevate levels of omega-3 fatty acids in the brain. This enhances neurotransmission and can result in increased energy levels. While the increased energy may seem beneficial, it can sometimes manifest as agitation, making it difficult to function. Anxiety: While some purport that one of krill oil's benefits is its ability to reduce anxiety, others end up experiencing increased anxiety from supplementation. If you experience an increase in anxiety, it's likely a result of the omega-3s within the oil that over-activate brain activity and certain neural pathways. Bloating: Many people notice that after they take their daily supply of krill oil, they begin to feel bloated. Bloating is a common side effect of krill oil supplementation and one that most people are willing to put up with. If the bloating is severe, it's probably a good idea to stop taking the krill. For most people, the bloating occurs on a random basis and is pretty easy to tolerate. Burping: Another extremely common side effect associated with krill oil is that of “burps.” We've all had cases of burping after swallowing any type of oil, and it can be unpleasant. You may notice the resurfacing of a krill taste in your mouth with each consecutive burp. Most people aren't too bothered by this, but if it's a problem, you could switch to a different krill supplier with an alternative encapsulation modality; this may reduce the burping. Depression: Despite the fact that many people claim krill oil helps improve their mood, others have found that krill oil actually amplifies their depression. This may be a result of increasing brain activity in certain areas and/or the omega-3 fatty acid contents altering neurotransmitter levels and efficiency. If you notice yourself becoming increasingly depressed after supplementation, it's probably a good idea to discontinue. Gas: Have you noticed an increase in flatulence after you started taking krill oil? Many people notice that it disrupts their digestion and can result in constipation, indigestion, and ultimately the passing of gas. This isn't the worst side effect, but may feel uncomfortable if it persists. Heartburn: Some people have complained about heartburn associated with krill oil supplementation. One suggested solution to avoid the side effect of heartburn is to take krill oil with a full meal. If the heartburn becomes difficult to deal with, try reducing your dose or discontinuing for awhile. Insomnia: The omega-3 fatty acids (DHA and EPA) within krill oil can significantly bolster energy levels and brain activity. Dopamine levels may increase and brain activity may become quicker â€" both of which may contribute to insomnia. If you've found it difficult to sleep at night due to racing thoughts before bed, it may be worth stopping the krill oil. Nausea: Feeling nauseous as a result of krill oil supplementation is a sign that you may have taken a rancid batch, an allergic reaction, or that you're unable to tolerate it. Nausea is generally a warning sign that a foreign substance is incompatible with your physiological homeostasis. Sleep disturbances: Some people notice a stimulating effect from supplementation of krill oil. This is likely a result of the omega-3 content, but the phospholipids and astaxanthin may also contribute to enhancing this effect. The increase in neurotransmitters and efficiency of neurotransmission can result in sleep difficulties such as insomnia, which stem from anxiety. Dizziness: If you become dizzy or experience Vertigo from krill oil, it could be a bad batch, or it could be that you just don't tolerate it. This is another sign of an allergic reaction, but could also stem from the influx of omega-3 fatty acids. As the brain adapts to the increase in omega-3s, neurotransmission or neural pathways may become altered; making you dizzy