If you need thyroid hormone, there are a number of options to choose from. In general, side effects are limited to the symptoms of hypothyroidism if you are not taking enough (dry skin, fatigue, weight gain, foggy brain, heavy periods, muscle aches, constipation, depression, feeling cold). If you take too much, then you might experience some of the symptoms of hyperthyroidism: anxiety, poor sleep, wired, more frequent stools, sweating and feeling hot all the time, higher heart rate, palpitations. If you experience any of these, especially after a dose change or a change in manufacturer or medication, notify your health care practitioner.
It is interesting to know the specific ingredients in a particular product. Some contain lactose, some dextrose (sugar), corn starch, and the like. The occasional person may have an allergic reaction to, or be intolerant of, one of the fillers or colors in the pill. If you are not doing well on one formulation, try another!
There are subtle differences between manufacturers, and one brand, even at the same dose, may cause you to feel a little differently. I prefer to use a brand name product instead of generic because then I can specify a particular brand name. If your insurance company decides to change the preferred brand, at least the pharmacy will notify me and we can decide what is best for you.
These days, fewer insurers are covering brand name thyroid hormone products at a low copay, and prior authorizations are rarely approved. If you find yourself on generic levothyroxine, realize that the manufacturers use the same high quality standards as the brand name products. The only issue is that on generic, you don’t know the manufacturer and may not be notified if the pharmacy switches to a different manufacturer’s product, unless the tablet looks different.
Thyroid hormone is best taken on an empty stomach, either 30 minutes or more before a meal, or 2 hours or more after eating. Never take thyroid hormone with iron or calcium, as they interfere with each other for absorption. Soy can also interfere with thyroid hormone absorption.
How do you know if your dose is right for you? I follow Thyroid Function Tests (TFTs). I generally like to see the TSH between 1-2, and free T4 and free T3 in the upper half of the normal range. However, everyone is different! You may feel best if your TSH is between 0.5-1, or your free T3 is a little above the normal range. Ideally, work with your doctor and follow your lab tests to individualize your treatment.
One important note: try to get your thyroid labs done at the same time of the day, ideally 6-10 hours after taking your pill.
The table below lists the different thyroid hormone options you have.
| Brand Name (Generic name) |
Description | Other ingredients |
| Synthroid (Levothyroxine) | Synthetic T4 | Acacia, confectioner’s sugar (contains corn starch), lactose monohydrate, magnesium stearate, povidone, and talc.
Different colors are in the different pill strengths, click here for a complete list. |
| Levoxyl (Levothyroxine) | Synthetic T4 | Microcrystalline cellulose, croscarmellose sodium, magnesium stearate, calcium sulfate dihydrate and sodium bicarbonate. Click here to see coloring additives. |
| Levothroid (Levothyroxine) | Synthetic T4 | Microcrystalline cellulose, calcium phosphate dibasic, povidone and magnesium stearate. Click here to see the coloring additives per tablet strength. |
| Tyrosint (Levothyroxine) | Synthetic T4
Gelcap formulation |
Gelatin, glycerin and water |
| Unithroid (Levothyroxine) | Synthetic T4 | Colloidal silicon dioxide, lactose, magnesium stearate, microcrystalline cellulose, corn starch, acacia and sodium starch glycolate. Click here to see coloring additives for different tablet strengths. |
| Levothyroxine | Generic synthetic T4, different manufacturers | Hard to know, need to contact the manufacturer for that information. |
| Armour Thyroid | Natural desiccated thyroid, porcine source
T4:T3 4:1
1 grain = 38 mcg T4 + 9 mcg T3 |
Calcium stearate, dextrose, microcrystalline cellulose, sodium starch glycolate and opadry white |
| Nathure-Throid | Natural desiccated thyroid, porcine source
T4:T3 4:1
1 grain = 38 mcg T4 + 9 mcg T3 |
Colloidal silicon dioxide, dicalcium phosphate, lactose monohydrate, magnesium stearate, microcrystalline cellulose, croscarmellose sodium, stearic acid, opadry II 85F19316 clear |
| Westhroid | Natural desiccated thyroid, porcine source
T4:T3 ratio 4:1
1 grain = 38 mcg T4 + 9 mcg T3 |
Colloidal silicon dioxide, dicalcium phosphate, lactose monohydrate, magnesium stearate, microcrystalline cellulose, croscarmellose sodium, stearic acid, opadry II 85F19316 clear |
| NP Thyroid | Natural desiccated thyroid, porcine source
T4:T3 ratio 4:1
1 grain = 38 mcg T4 + 9 mcg T3 |
calcium stearate, dextrose (agglomerated) and mineral oil |
| Cytomel (Liothyroinine) | Synthetic T3 | Calcium sulfate, gelatin, starch, stearic acid, sucrose and talc |
| Liotrix (Thyrolar) | Synthetic T4 and synthetic T3
T4:T3 ratio 4:1 |
Calcium phosphate, colloidal silicon dioxide, corn starch, lactose, and magnesium stearate. Click here for list of colors and dyes. |
| Compounded Thyroid | Tailored doses of T4 and T3 | Prepared by compounding pharmacies; ratios and doses customizable.
Immediate or slow release. Free of allergenic fillers. |
To your health,
Patty Powers, MD
www.drpattypowers.com
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