Hypothyroidism Medication
The tables below have details about synthetic and natural medication for hypothyroidism. For more information at this site, see the links in the column at the right as well as Thyroid Function, T3 Supplementation, and Desiccated Thyroid pages.
On this page:
Synthetic T4 (T-4) |
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| Some brand names |
Eltroxin, Levothroid, Levoxyl, Oroxine, Synthroid, Unithroid. |
| Pharmaceutical names |
Thyroxine, l-thyroxine, thyroxine sodium, levothyroxine sodium. |
| Hormone content |
T4 only. |
| Uses |
By itself, with the expectation that some of the synthetic T4 will convert to T3; in combination with synthetic T3. |
| Availability |
In most or all countries. |
| Physician knowledge |
Virtually all doctors are familiar with it and will prescribe it for patients they have diagnosed with hypothyroidism. |
| Dietary considerations |
Most brands contain lactose as a filler. Levothroid and Levoxyl do not. |
| Stability |
Known to have "significant stability and potency problems." |
| Adjustment flexibility |
For people on T4 alone, dose adjustment is easy; pills come in a variety of sizes.
See T3 adjustment flexibility for people on separate T4 and T3 medications. |
| Other advantages |
For many thyroid patients, synthetic T4 alone is enough to return them to normal health.
Each brand has different fillers; with a variety of brands to choose from, patients can try different brands if they react to the fillers in one brand. Also, some patients do better on one brand than on another. |
| Other disadvantages |
Although lab results may not indicate a problem, clinical symptoms of hypothyroidism can remain after treatment with T4 alone or sometimes even a combination of synthetic T4 and T3. |
Synthetic T3 (T-3) |
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| Some brand names |
Cytomel (the US and Canada), Tertroxin (the UK), Cynomel (France). |
| Pharmaceutical names |
Triiodothyronine, liothyronine, liothyronine sodium. |
| Hormone content |
T3 only. |
| Uses |
Usually in combination with synthetic T4; occasionally, as a treatment in itself. |
| Availability |
Not available in all countries or at all pharmacies. |
| Physician knowledge |
Despite the large number of medical articles on this topic, it can be difficult to find a doctor who is willing to prescribe T3 in addition to T4. |
| Dietary considerations |
Cytomel (and possibly other brands) contains lactose as a filler. |
| Stability |
No known problems. |
| Adjustment flexibility |
When taking both synthetic T4 and T3 as separate pills, the ratio of T3 to T4 can be adjusted. However, the absorption of T4 is so variable (from 40 to 72 percent) that the ratio cannot be said to be constant.
Occasionally, T3 is used as a treatment in itself. |
| Other advantages |
For many patients, taking T3 in addition to T4 has relieved symptoms of hypothyroidism that wouldn't disappear on T4 alone. |
| Other disadvantages |
T3 is faster acting than T4, so patients usually take it two or more times a day to avoid having their energy levels crash when the effects of T3 wear off. (However, timed-release T3 is also available.)
Pure T3 cannot be used by itself during pregnancy. Much of the fetus depends on a good supply of T4.
Those taking synthetic T3 with T4 need to take two types of pills and have two prescriptions filled instead of just one. |
Synthetic T4/T3 combination |
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| Brand name |
Thyrolar. |
| Pharmaceutical name |
Liotrix. |
| Hormone content |
T4 and T3. |
| Uses |
By itself, as a T4/T3 combination thyroid replacement product. |
| Availability |
Available only in the US. |
| Physician knowledge |
Not a well-known drug. |
| Dietary considerations |
Contains lactose as a filler. |
| Stability |
No known problems. |
| Adjustment flexibility |
The ratio of T3 to T4 is fixed, so it can't be adjusted unless T4-only or T3-only pills are taken as well. |
| Other advantages |
For many patients, taking a T4/T3 combination has relieved the symptoms of hypothyroidism that weren't reversed by T4 alone.
Only one pill and one prescription are required to get both T4 and T3. |
| Other disadvantages |
Thyrolar must be kept refrigerated (but it can be left unrefrigerated for up to a week). |
Desiccated Thyroid (Thyroid Extract) |
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| Brand names |
Armour (US and imported to other countries, by Forest Pharmaceuticals), Nature-throid (US, by Western Research Laboratories), Thyroid (Canada, by Erfa, formerly by Pfizer Canada and before that by Parke-Davis), Westhroid (US, Western Research Laboratories). |
| Hormone content |
T4, T3, and probably (unassayed) T2 and T1. |
| Uses |
By itself, as a complete thyroid hormone replacement product; sometimes in combination with synthetic T4 or T3 to change the ratio of T4 to T3. |
| Availability |
Available at most pharmacies in the US and Canada; in other countries, it often has to be specially imported. |
| Physician knowledge |
Teaching about it in medical schools stopped suddenly in 1975, and many doctors are untrained in its use. |
| Dietary considerations |
Natural; derived from pigs' thyroids.
Doesn't contain lactose. |
| Stability |
Doesn't have the stability problems that synthetic T4 medications are known for. |
| Adjustment flexibility |
The ratio of T3 to T4 is fixed, so it can't be adjusted unless T4-only or T3-only pills are taken as well. |
| Other advantages |
Provides all the thyroid hormones in one pill.
Absorbed more completely and consistently than pure T4 because all the hormones are protein-bound, which is the natural way for the hormones to be absorbed.
In the natural, desiccated form, T3 appears to spread out its effects more evenly, causing fewer of the ups and downs that patients often experience with synthetic T3.
For many patients, taking desiccated thyroid instead of T4 alone or even a T4/T3 combination relieves the symptoms that didn't reverse on the other medications.
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| Other disadvantages |
It can be difficult to find a doctor who will prescribe it.
If the T4/T3 ratio isn't optimal, another prescription is needed with it. |
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Hypothyroidism Treatment Files
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Hypothyroidism Treatment
An overview of treatment for hypothyroidism and the pages in this section
Hypothyroidism Treatment History
Early treatment, synthetics until the present, the standardization hoax, and links to more information
Hypothyroidism Medication
Brand names, content, availability, physician knowledge, and other information about synthetic T4, synthetic T3, synthetic T4/T3 combination, and desiccated thyroid
Hypothyroidism Medication Comparison
A side-by-side look at synthetic T4, synthetic T3, synthetic T4/T3 combination, and desiccated thyroid comparing the above information
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