Do You Feel Better on Armour Thyroid Than Synthroid?

An underactive thyroid gland is a very common condition. In fact, levothyroxine, the hormone generally used to treat hypothyroidism, is the most commonly prescribed drug in the US. After a period of dose adjustment, many people do quite well on this medication. But others do not feel good despite rigorous treatment. Natural desiccated thyroid such as Armour Thyroid from pigs contains more than one kind of thyroid hormone. Would you feel better on Armour Thyroid than on levothyroxine?

Why Don’t Doctors Like Armour Thyroid?

Q. I was happy taking Armour thyroid, but it became more and more difficult to get a prescription. Eventually my doctor just refused to prescribe it for me. Why don’t doctors understand that some people do better on natural thyroid rather than synthetic levothyroxine?

A. Medical students were once taught that a natural desiccated thyroid extract (DTE) such as Armour Thyroid is not as reliable as synthetic levothyroxine (Levoxyl, Synthroid, Tirosint). But not all people with hypothyroidism thrive on levothyroxine alone.

Benefits of Adding T3 to the Regimen:

Levothyroxine, also known as T4, must be converted to the active thyroid hormone T3 to do its work. Some people have an enzyme that is less efficient at managing that conversion. That could explain why they feel better on a desiccated thyroid extract like Armour, which contains both hormones.

A recent study suggests that people who take T3 (liothyronine) as part of their treatment for hypothyroidism have a reduced risk of dementia and early mortality (Journal of Clinical Endocrinology and Metabolism, June 20, 2025). Previous studies have also suggested that some patients, like you, prefer treatment with desiccated thyroid extract.

One small study followed patients for six months after their thyroid glands were surgically removed (Frontiers in Endocrinology, March 10, 2025). The investigators report that those receiving a combination of thyroid hormones normalize their T4 and T3 levels more readily than those receiving levothyroxine alone. In addition, their cholesterol levels and weight were less likely to increase. This suggests that people who can’t make their own thyroid hormones do better on a combination regimen, although that is not the usual treatment.

Treating Hypothyroidism Symptoms:

Q. I’ve been on Armour thyroid for 35 years. Back when I was first diagnosed, I had all the typical signs of hypothyroidism: terrible fatigue, dry skin and trouble staying awake. I always felt like I was freezing.

At first, my physician prescribed Synthroid [levothyroxine, aka T4]. When it had almost no effect, he switched me to Armour thyroid. It was like I became alive again. Both T3 and T4 thyroid hormones have been in the range ever since, and I am active and awake. Have other people reported the same benefit?

A. Many readers with hypothyroidism agree that desiccated thyroid extract (DTE) makes them feel better. There is even science to support this observation.

Would You Feel Better on Armour?

Q. About two decades ago, I was diagnosed with hypothyroidism. I took levothyroxine (Synthroid) for a few years and then was switched to Armour Thyroid. My wife was also taking Armour and we both thought we felt better on it.

Then we couldn’t get Armour for many months and had to go back to Synthroid. When Armour once again became available, we happily went back to it.

I told my endocrinologist about this back-and-forth switch, with both my wife and I preferring Armour to Synthroid. He said that most of his patients prefer desiccated thyroid. What’s the difference?

What Is the Difference Between Synthroid and Armour?

A. Levothyroxine (Levoxyl, Synthroid) is a synthetic hormone that only contains T4 thyroid hormone. The body has to change T4 to the active form, T3. To do that, an enzyme knocks one iodine atom off the molecule. Some people have a harder time with this conversion, presumably because their genes encode a less active enzyme.

Armour thyroid is a natural product derived from dried animal glands. (Other brands include Nature-throid and Westhroid). Desiccated thyroid gland contains both T3 and T4, which may explain why some people prefer this formulation. The ratio of T3 to T4 in Armour is not quite the same as the ratio produced by a healthy human thyroid gland, however. Consequently, doctors are sometimes reluctant to prescribe it.

Does Armour Cause Problems for Older People?

Q. I’ve read your articles on Armour Thyroid and asked my doctor to change my Synthroid prescription to Armour. He responded that he doesn’t like to prescribe Armour Thyroid to patients over 65. Why do you suppose that is?

A. We don’t know for sure, but we suspect some doctors worry about cardiovascular complications (Vnitrni Lekarstvi, Winter 2018). Excess thyroid hormone could cause heart palpitations or arrhythmias. As a result, doctors start older patients on very low doses of levothyroxine and increase the dose extremely gradually (Medical Letter on Drugs and Therapeutics, Feb. 20, 2023). Although it is not clear that desiccated thyroid extract results in higher doses of T4 or T3, physicians may fear that they can’t control the dose properly.

What Do Thyroid Patients Say?

This concern might be primarily theoretical, however. A study of hypothyroid patients taking synthetic levothyroxine (Synthroid or others), combination levothyroxine and triiodothyronine (T4 and T3) or desiccated thyroid extract (Armour) found no additional cardiovascular risk from combination or natural therapy (Southern Medical Journal, June 2018).

Learn More:

You are not the only one to report benefit on desiccated thyroid extract. To learn more about the differences between various thyroid formulations and why they matter, you may wish to read our eGuide to Thyroid Hormones. It is an in-depth online resource.

You may also wish to listen to our hour-long interview about hypothyroidism and its treatment with Dr. Antonio Bianco. It is Show 1330: Rethinking Hypothyroidism.