The thyroid is an endocrine gland located in the neck. It secretes two hormones into the blood, such as triiodothyronine and thyroxine Moreover, these thyroid hormones are responsible for regulating the energy, metabolism and growth.
Check out this Cartoon on how your thyroid works. Thyroid issues can get complicated, so this might help explain a little bit better what dotors do not explain to their patients. Check out that T-shirt here: