The list of warning signs and symptoms of selenium toxicity. Are you taking too much selenium? Here's how to find out: Selenium is a very important micronutrient for your body. It is included in certain proteins, called selenoproteins, that enable your cells to function properly, reduce inflammation, and produce antioxidants. Many people suffer from selenium deficiency which leads them to use selenium supplements. That's all good but what happens when they take too much? They may end up with minor signs of selenium toxicity. True selenium toxicity is rare, but a slight amount of selenium toxicity isn't uncommon and can occur if you accidentally take too much selenium in your supplements! This is often a problem for patients with thyroid disease because they know that using selenium can help reduce thyroid gland inflammation. Minor symptoms of selenium toxicity include: - Hair loss - Brittle nails - Fatigue - GI problems - Joint pain - Nausea These are more common than the serious sy...