Quality CareFind out why Mayo Clinic is the right place for your health care. Make an appointment.
Meet the StaffFind a directory of doctors and departments at all Mayo Clinic campuses. Visit now.
Research and Clinical TrialsSee how Mayo Clinic research and clinical trials advance the science of medicine and improve patient care. Explore now.
Visit Our SchoolsEducators at Mayo Clinic train tomorrow’s leaders to deliver compassionate, high-value, safe patient care. Choose a degree.
Professional ServicesExplore Mayo Clinic’s many resources and see jobs available for medical professionals. Get updates.
Give to Mayo ClinicHelp set a new world standard in care for people everywhere. Give now.
Mayo Clinic offers appointments in Arizona, Florida and Minnesota and at Mayo Clinic Health System locations.
Subscribe to Housecall
Our general interest e-newsletter keeps you up to date on a wide variety of health topics.
Most doctors recommend levothyroxine, the synthetic form of thyroxine (T-4). However, natural extracts are available that contain thyroid hormone derived from the thyroid glands of pigs. These products — Armour Thyroid, for example — contain both levothyroxine and triiodothyronine.
Doctors have a number of concerns about natural thyroid hormone extracts such as Armour Thyroid, including:
Still, researchers have investigated whether adjusting standard hypothyroidism treatment to replace some T-4 with T-3 may offer benefit. The majority of studies have determined that the addition of T-3 does not offer any advantage over treatment with T-4 alone.
However, there is some evidence that T-3 may offer benefit to certain subsets of people, such as people who have had their thyroid surgically removed (thyroidectomy). Research is ongoing.
Mayo Clinic is a not-for-profit organization. Make a difference today.
Mayo Clinic is a not-for-profit organization. Proceeds from website advertising help support our mission. Mayo Clinic does not endorse non-Mayo products and services.
Check out these best-sellers and special offers on books and newsletters from Mayo Clinic.
A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "EmbodyHealth," "Enhance your life," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.
We comply with the HONcode standard for trustworthy health information: verify here.