Did you know that one in every eight women will become hypothyroid at some point during their lifetime. This risk increases with age, and women over the age of 60 are particularly susceptible.
While there are many causes for low thyroid hormone function, most health care providers never look for the underlying cause(s). A woman goes in for blood work, her TSH is high, and the doctor prescribes levothyroxine (the generic form of Synthroid)…end of story.
If you’ve been diagnosed with hypothyroidism, it’s important that the underlying cause be investigated because your hypothyroidism may be reversible without medication. However, if your hypothyroid condition requires treatment with thyroid medication, you’ll want to know about all the options so you can make an informed decision about which one is right for you.
Overview of Thyroid Medications
Thyroid medications primarily include three types: synthetic, porcine, and compounded. The most common synthetic thyroid hormone is levothyroxine. Brand names for levothyroxine include Synthroid, Levoxyl, Tirosint, and Euthyrox.
Porcine thyroid hormones are derived from pig thyroid glands and are known as desiccated thyroid extract (DTE). Brands like Armour Thyroid and Nature-Throid fall into this category.
Levothyroxine (T4)
Levothyroxine is T4 is the usual 'go to' thyroid hormone prescribed for hypothyroidism. Examples of T4 only medications are Synthroid (generic version is Levothyroxine), Levoxyl, and Tirosint. T4 is actually a prohormone. It is a very weak form of thyroid hormone. It must be converted into T3, the more active form of thyroid hormone, in order to be fully effective.
Most studies on thyroid medications have been done with T4 only preparations. There are a few studies which have examined the benefit of adding T3, but the results have been mixed. So, most doctors do not prescribe T3 with T4. The problem with this approach is that there are a lot of things that prevent T4 from converting into T3!There are a couple of other things to keep in mind with T4 preparations, aside from inefficient conversion to T3. The generic brands typically do not work as well, and all forms usually contain fillers which can not only cause hypersensitivity and but also impair the absorption of the thyroid medication it contains.
Liothyronine (T3)
T3 is the active thyroid hormone that works at the cellular level to help deliver oxygen and energy to cells, tissues, and glands throughout the body. It is uncommon for a hypothyroidism patient to be prescribed T3-only treatment without T4; typically, liothyronine is used in combination with T4.
The main T3 preparation available is synthetic Liothyronine (brand equivalent is Cytomel). It’s only available in doses of 5 mcg and 25 mcg. It must be taken at least two to three times daily because its effects don't last very long (peak action is usually within about three to four hours). As in the case of commercially available T4, Liothyronine, especially the generic form, contains several fillers (i.e. corn, talc) which may cause side effects and reduce the effectiveness of the medication.
Porcine Thyroid Extracts
Armour Thyroid, Nature Thyroid, NP Thyroid, and WP Thyroid are made from the thyroid glands of pigs. Some health care providers believe they work better in some patients because they are “more natural” AND contain both T3 and T4.
The upside to these types of thyroid medications is that they usually only need to be taken once a day. Many of my patients forget to take their afternoon dose of commercially available T3. However, there are some potential downsides. For one, there are differences in doses and fillers in each of these preparations that impact how well they work. For instance, NatureThyroid contains lactose as a filler. Another potential drawback is that your body may develop antibodies to pork. In some cases, this explains why porcine thyroid may work well in the beginning but then stop working later.
Another important thing to keep in mind with pig derived thyroid medications is that they can potentially make autoimmune thyroid disease worse. I typically do not use these medications in patients with autoimmune thyroid disease (or any other autoimmune disease for that matter). This should make sense…if your body is attacking your own thyroid, what do you think it will do with pig thyroid??
Compounded Thyroid Preparations
Compounded thyroid medication is custom-made medication mixed and prepared specifically for you by a compounding pharmacy based on a prescription written by your healthcare provider. Compounded drugs don't have "brand names” because they are not made by pharmaceutical companies.
Thyroid medication can be compounded using levothyroxine (T4), liothyronine (T3), and porcine thyroid hormone, in any combination and dosage. If your healthcare provider prescribes compounded thyroid medication for you, make sure thecompounding pharmacy receiving the prescription is accredited by the Pharmacy Compounding Accreditation Board. This accreditation confirms the compounding pharmacy has gone through the rigorous process of meeting strict, high standards.
Compounding thyroid medication most commonly comes in capsule form. In addition to the active medications, the capsule will usually include additional fillers. Common fillers used in compounding include lactose, acidophilus, calcium carbonate,\ mannitol, starch, tapioca powder, sodium bicarbonate, silica gel, hydroxypropyl methylcellulose, and Avicel (microcrystalline cellulose). Also, compounded thyroid medications are not approved by the FDA because each prescription is custom made for a patient. These medications are typically more expensive than generic and brand-name thyroid medications, and they are not covered by health insurance. One final issue with compounded thyroid medications is related to absorption. Since these formulations are dispensed as sustained release capsules, they rely on healthy gut function to be properly absorbed and processed. Patients with gut issues, or those who take medications affecting stomach acidity, may not be good candidates for compounded thyroid medication.
Monitoring and Managing Thyroid Medication
Monitoring thyroid medication requires regular blood tests to ensure proper dosing. Patients should consistently take medication at the same time each day for optimal absorption. While most conventional medical practitioners typically only order a TSH, this does not provide a complete picture of overall thyroid hormone function. A full lab panel should include:
TSH, Free T4, Free T3, and reverse T3. In patients with Hashimoto’s hypothyroidism, Thyroid Peroxidase Antibodies and Anti-thyroglobulin Antibodies should also be routinely checked.
*NOTE: The optimal time to take your thyroid medication is FOUR HOURS prior to having your blood work done. The blood work needs to be done in the morning and fasting (nothing to eat or drink except for water after midnight).
Other Key Points
1. Several medications can interact with thyroid medications and alter their effectiveness.
a. Calcium supplements: Can reduce absorption of levothyroxine.
b. Iron supplements: Decrease thyroid medication absorption.
c. Cholestyramine: These are cholesterol lowering drugs that can bind thyroid hormones in the gut and prevent them from being absorbed.
d. Antidepressants: Certain types can increase the effect of thyroid hormone medications.
e. Antacids and Proton Pump Inhibitors: Interfere with thyroid medication absorption.
2. Once your thyroid treatment is optimal and your symptoms are under control, you should continue taking the same brand of thyroid medication. Since commercially available T4 and T3 are made by numerous different manufacturers, the potency can vary between 95 to 105%. If you change brands or manufacturers, or if you change from one generic levothyroxine to another, you might experience potency variation that may negatively affect your thyroid function. Confirm with your pharmacy your thyroid medication refills come from the same manufacturer to ensure you get consistent thyroid hormone levels. If you do switch brands or medications, you need to retest your thyroid hormone levels again in four to six weeks to make sure no dose adjustments are needed.
3. Take your thyroid medication at the same time every day: First thing in the morning, on an empty stomach, with a glass of water. Thereafter do not eat, drink anything except water, and take any other medications or supplements for ONE HOUR. If you have a habit of forgetting to take your daily thyroid medication, set a daily alarm to remind you.
Keep your medicines in a place like your bedside table so they are more easily visible.
4. Thyroid medications are sensitive to humidity, heat, and moisture and will lose potency if not properly stored.
Always keep your thyroid medications in a cool, dark place, ideally at a temperature of 68–77°F (20–25°C), and protected from light and moisture. You should especially consider this if your thyroid hormone medications are delivered to you by mail, especially during the hot summer months.
Final Thoughts
There is no “right thyroid medication” for every woman. The underlying cause of hypothyroidism, each woman’s unique health history, and how a woman responds to the medication should help to guide the practitioner on which medication to use. Sometimes the initial choice is the right one. Other times, a variety of medications or combination of medications must be tried before the ‘best solution” is found.
The key thing to remember is that you should always take both T4 AND T3 for optimal results. This may be a tough sell to a hard line conventionally trained health care practitioner. Most of them will not prescribe T3 because they believe it isn’t necessary. If you find yourself butting heads with your doctor, seek out a functional or integrative medicine health care provider instead.