is thyroid hormone to replace the hormone your thyroid may not be making. Any symptoms of hypothyroid? Hair loss, fatigue, muscle pain, constipation, depression, neck pain, GERD, joint pain, etc? If you occasionally get the opposite symptoms, anxiety, diarrhea, rapid heart rate, then you could very well have Hashimoto's and be swinging from hyper to hypo. Hashi is the most common cause for hypothyroidism in developed countries.