Lots of people think mood only relates to serotonin levels in the brain, but that’s only part of the story. Think of it this way: So your mood depends on the right balance of nutrients, hormones, and other chemical messengers throughout your entire body—including your gut, thyroid, and immune system. This is not an exhaustive list, but to give you some examples, here are 5 root causes of mood issues that we investigate when taking a functional medicine approach. 1️⃣ Hormonal