Symptoms of reduced thyroid (or hypothyroid) activity can include:

• a tendency to gain weight
• cold hands and feet
• lack of sweating
• fatigue
• dry skin and hair
• a tendency towards constipation

Symptoms of overactive thyroid (or hyperthyroid) activity can include:

• excessive sweating
• hyperactivity
• irritability
• nervousness
• oily hair and skin
• occasional tendency towards frequent bowel movements or diarrhea during times of stress