Determine if T3 - the active form of thyroid hormone - is beneficial in fibromyalgia. Determine the feasibility and promise of an appropriately powered future prospective randomized controlled study of using T3 (the active form of thyroid hormone) for the treatment of fibromyalgia. We specifically aim to assess the feasibility, cost, obstacles and promise of conducting a prospective controlled study in the future.

Inclusion Criteria:

1. Age 18-50
2. Meet american college of rheumatology criteria for fibromyalgia
3. at baseline report an average pain of 4 or more on a brief Pain Inventory.
4. can climb 2 flights of stairs without shortness of breath.

Exclusion Criteria:

1. new medication change in the last 2 months
2. any cardiac disease at all
3. known thyroid disease before or after thyroid screening bloodwork
4. unstable medical or psychiatric disease.
5. Known inflammatory or rheumatic disease other than fibromyalgia
6. substance abuse in the last year
7. suicidality or depression as indicated by a Beck Depression Inventory of 30 or above
8. concomitant herbal medications
9. multiple severe medication allergies
10. the assessment of the research team that inclusion of the subject could in some way compromise the safety and validity of the study.
11. diabetes
12. smoking
13. Known uncontrolled hypertension
14. known uncontrolled hypercholesterolemia

Each participant received placebo followed by 25 mcg of T3.

Adverse event data was collected over the 12 week course of the study.

The clinicaltrials.gov definition of adverse event was used. Adverse events were monitored without regard to the specific Adverse Event Term.