Synthetic vs. Natural Thyroid Hormone: Breaking Down The Ingredients
Published March 31 2014
Many of the patients I work with who have hypothyroid conditions are taking thyroid hormone. Most are taking synthetic thyroid hormone, while some are taking natural thyroid hormone. While the goal should be to restore the person’s thyroid health so that they don’t need to take thyroid hormone, some people do need to take thyroid hormone on a temporary basis. And of course some people need to take thyroid hormone on a long-term basis. But many people who take thyroid hormone aren’t aware of the ingredients, and so I’ve decided to write an article about this.
Synthetic Thyroid Hormone. There are numerous brands of synthetic thyroid hormone, but I’m going to focus on a few of the more common brands.
Synthroid. This is synthetic T4, and if you visit www.rxlist.com, it currently states that ” Synthetic T4 is identical to that produced in the human thyroid gland (1). But right below this the inactive ingredients are listed, which include acacia, confectioner’s sugar (contains corn starch), lactose monohydrate, magnesium stearate, povidone, and talc. And then below this you’ll see some of the color additives, which include FD&C Yellow No. 6 (in 25 mcg tablets), FD&C Red No. 40 and FD&C Blue No. 2 (in 75mcg strength), etc.
So when you factor in the inactive ingredients it becomes quite obvious that taking synthetic T4 isn’t identical to thyroid hormone which is produced by the thyroid gland. And while it’s true that many people seem to do fine when taking synthetic thyroid hormone and don’t react to these ingredients, others don’t do fine. And when someone experiences an increase in symptoms upon taking thyroid hormone, sometimes this is due to the ingredients. For example, if someone is sensitive to corn, then they very well might react to synthetic thyroid hormone.
Levoxyl. Another brand of synthetic T4. The ingredients include Microcrystalline cellulose, croscarmellose sodium, magnesium stearate, calcium sulfate dihydrate and sodium bicarbonate, along with color additives depending on the tablet strength (2).
Levothroid. Another brand of synthetic T4. The ingredients include Microcrystalline cellulose, calcium phosphate dibasic, povidone and magnesium stearate, along with color additives depending on the tablet strength (3).
Cytomel (liothyronine sodium). This is a brand of synthetic T3. The inactive ingredients consist of calcium sulfate, gelatin, starch, stearic acid, sucrose and talc (4).
Here are the ingredients of Armour and Nature-Throid, which are two of the most common forms of dessicated thyroid hormone:
Armour. This is a form of natural thyroid hormone that is derived from porcine thyroid glands. It consists of both T3 and T4, and many people do better when taking natural thyroid hormone when compared to synthetic thyroid hormone. However, some people react to the ingredients of Armour. The inactive ingredients include calcium stearate, dextrose, microcrystalline cellulose, sodium starch glycolate and opadry white (5).
Nature-Throid. This is another form of natural thyroid hormone that is derived from porcine thyroid glands, and therefore also consists of both T3 and T4. The inactive ingredients include colloidal silicon dioxide, dicalcium phosphate, lactose monohydrate, magnesium stearate, microcrystalline cellulose, croscarmellose sodium, stearic acid, Opadry II (6).
Is There Gluten In Your Thyroid Hormone Medication?
Many people with Hashimoto’s Thyroiditis attempt to avoid gluten. However, most people don’t consider that their source of thyroid hormone medication might include gluten. Although both Armour and Nature-Throid are gluten free, not all forms of levothyroxine are gluten free. According to the website www.glutenfreedrugs.com, the only two brands of levothyroxine which are guaranteed to be gluten free include Lannett and Mova. Apparently the manufacturers of Synthroid can’t guarantee that this is gluten free. Both Levothroid and Levoxyl are gluten free. Cytomel is also gluten free.
Which Form/Brand Of Thyroid Hormone Should You Take?
If someone needs to take thyroid hormone then in most cases I’m more in favor of them taking Armour or Nature-Throid. And the reason for this is because 1) natural thyroid hormone consists of both T3 and T4 (as well as T1 and T2), 2) there are no color additives in natural thyroid hormone, and 3) both Armour and Nature-Throid are gluten free. With that being said, some people do better when taking synthetic thyroid hormone, and some people (i.e. strict vegetarians and vegans) choose synthetic thyroid hormone for ethical purposes.
If someone needs to take thyroid hormone but currently isn’t taking any, and they are open to taking either synthetic or natural thyroid hormone, then in most cases I would recommend for them to take either Armour or Nature-Throid. On the other hand, if someone is already taking synthetic thyroid hormone and is doing fine, it might be best for them to stay on this. If they are taking either synthetic or natural thyroid hormone and aren’t doing well, then it might be a good idea to switch to a different brand. For example, if someone is taking Synthroid and isn’t doing well, then perhaps they should consider switching to the brands Lannett or Mova.
Consider Using a Compound Pharmacist
Another option is to go to a compound pharmacy and let them know that you need a gluten free and dairy free option of thyroid hormone medication. Most compound pharmacists will be able to use hypoallergenic ingredients. Another option is a compounded thyroid hormone that has both T3 and T4 in a sustained-release form. This would be a synthetic product, but a sustained-release form helps to prolong the activity of T3, which has a short half-life. One important thing to keep in mind is that not all compound pharmacies are the same, as you want to make sure they source the highest quality chemicals and have procedures in place to ensure quality of the final preparation.
Of course many times the reason a person isn’t doing well has nothing to do with the ingredients in the thyroid hormone they’re taking, but is instead due to other factors (i.e. weak adrenals, a vitamin or mineral deficiency, leaky gut syndrome, etc.). But one shouldn’t overlook the potential negative effect that can take place if they are sensitive to one of the ingredients in synthetic or natural thyroid hormone. For example, if someone is sensitive to corn, then they might react when taking either synthetic thyroid hormone or Armour, as both have corn starch. However, Nature-Throid has the ingredient lactose monohydrate. And although a very small amount of lactose is included, those who have a severe lactose intolerance might experience symptoms.
The truth is, just about everything written in this post is easily accessible by doing some simple research. And while I realize that some people reading this already have done some of this research, and therefore are aware of the ingredients in thyroid hormone, I think it’s safe to say that most people who take thyroid hormone aren’t aware of the ingredients present. Most people don’t bother reading ingredients, but in this day and age it is important to be aware of the ingredients in the food you eat, as well as any medications you take. This of course isn’t just the case with synthetic and natural thyroid hormone, but any other prescription or over-the-counter medications you might take.