Lots of people are on levothyroxine (name brand Synthroid) to replace a sluggish thyroid.  Many like taking too much thyroid—as it may help you lose weight, feel more energetic, need less sleep.  But, there is a downside.  You may feel anxious, have insomnia, and have an irregular or fast heart rate.

TSH is a lab test that should be repeated once a year.  This yearly blood work will confirm if your current dose is the right dose.  If the TSH is low, this shows the strength of your pill is too high.  Getting too much thyroid replacement has been shown to increase risk of coronary heart disease deaths and atrial fibrillation (an irregularity in heart beat).  Too much thyroid was not shown to increase cancer or stroke mortality.

My advice:  Get yearly TSH lab work.  Take the correct dose of thyroid replacement.  It’ll do your heart good and you may live longer.