Lactose: Why Nature-throid & WP Thyroid Aren’t Working

Over the years we’ve seen more and more formulations of NDT fall out of favor with patients. 

Thyroid medications such as Nature Throid and Armour thyroid used to be widely considered as some of the best thyroid medications on the market but now more and more people are having trouble with them. 

And by trouble, I’m talking about people who were feeling great on them only to find out that the medication is no longer working for them. 

A pretty big deal if you are a hypothyroid patient who finally got control of your symptoms. 

But why is this? 

What is causing these medications to suddenly stop working? 

That’s exactly what we are going to explore today. 

We are going to look at two types of NDT formulations, Nature Throid and WP thyroid, and talk about some recent changes to these medications which may render them INEFFECTIVE for many of you out there. 

This information is important if you are currently taking them or if you are considering using them in the future. 

Let’s jump in…

Lactose Monohydrate in Nature-Throid and WP Thyroid

Before I talk about some of the changes to these formulas I want to take a second just to lay some framework here for those who aren’t familiar with NDT medications. 

NDT stands for Natural Desiccated Thyroid and NDT is a broad term used to describe a class of prescription thyroid medications which all share similar characteristics. 

These medications all come from crushing up animal (usually pig) thyroid glands and then drying up the formulation to produce a thyroid medication that humans then consume. 

These medications are considerably more potent than thyroid medications such as levothyroxine and Synthroid because they contain the active thyroid hormone T3 in addition to T4 (T4 is the only hormone found in levothyroxine/Synthroid). 

For a long time, these medications were the preferred thyroid hormone replacement for thyroid patients. 

Anecdotal evidence, as well as medical research, shows that this is the case as patients who use NDT medications experience more weight loss and experience fewer thyroid symptoms compared to those who use other medications. 

But one by one these medications have started to falter such that they are no longer working as well as they used to. 

The exact reason for this is unclear, especially as many pharmaceuticals deny major changes to the medication formula, but patients continue to experience negative side effects after these changes take place. 

When it comes to Nature Throid and WP Thyroid, one reason that these medications no longer work as well as they used to probably comes down to 1 single ingredient. 

Lactose monohydrate. 

Lactose monohydrate is found in both Nature Throid and WP thyroid formulations per their own ingredient lists which you can read below:

• Nature Throid ingredient list (1)
• WP thyroid ingredient list (2)

Lactose monohydrate was recently added to the thyroid USP ingredient which forms the backbone of both of these medications (and other NDT formulations, by the way). 

Thyroid USP is the desiccated thyroid component and the part which contains the active thyroid hormones T4 and T3. 

And recently the United States Pharmacopeia changed the formula of this important ingredient to include lactose monohydrate in the diluent. 

Why does it matter? 

Because lactose monohydrate, exactly as the name implies, contains the ingredient lactose. 

And lactose can negatively impact thyroid medication (more on this below) in several key ways. 

How Lactose Impacts Thyroid Medication

Lactose may not seem like a big deal to many of you but it actually has a profound impact on thyroid medications. 

In fact, I believe that one of the main reasons that Synthroid and levothyroxine are so poorly tolerated is for exactly this reason. 

They both contain lactose monohydrate (3) (see ingredient list below) and you can probably attest to how well these medications “work” if you’ve ever used them before. 

Why does lactose cause such a big problem for thyroid patients?

For several reasons:

#1. Lactose, even in small amounts, can cause inflammation and damage to the intestinal tract. 

We know from research that up to 65% of adults have a problem digesting lactose (4) to one degree or another! 

That’s 65% of the entire population which is literally billions of people. 

So if you think that this doesn’t impact you, think again. 

Furthermore, we know that when these people come into contact with lactose, and if they are not able to digest it appropriately it will cause any or all of the following symptoms (5):

• Abdominal pain
• Gas production
• Gas pain
• Diarrhea
• Nausea

And these symptoms can then go on to impact your intestinal microflora, the ratio of good to bad bacterial in your gut, inflammatory markers in your gut, and more. 

Consuming lactose, if you are intolerant, is obviously not advisable whether you have a thyroid problem or not. 

#2. Thyroid medications are notoriously difficult to absorb, even without intestinal problems. 

The symptoms listed above become even more of an issue for thyroid patients because ALL thyroid medications (except for Tirosint) are very difficult to absorb in the intestinal tract. 

This is why doctors recommend that you take your thyroid medication on an empty stomach, why you shouldn’t take your supplements at the same time as your medication, why you should avoid taking your medication with coffee, and so on. 

All of these impact your ability to ABSORB your thyroid medication in the GI tract. 

Imagine adding an ingredient to the medication you are taking which makes this process even MORE difficult. 

And that’s exactly what is happening with medications like Synthroid and now Nature Throid and WP thyroid. 

#3. Many people are allergic to lactose and this is even more prevalent among the thyroid population. 

Dairy proteins and sugars, such as lactose, are even more problematic for the thyroid population compared to the regular population. 

The most common cause of low thyroid function in the United States (and most developed countries) is the autoimmune condition Hashimoto’s thyroiditis. 

Just looking at the numbers, there is about a 70-90% chance you have Hashimoto’s (whether you realize it or not) if you have low thyroid function and if you are taking thyroid medication. 

And these patients tend to have a major problem with dairy, in general, which is why I recommend that they avoid it. 

Dairy seems to negatively impact immune function and because Hashimoto’s is an immune-mediated disease, it seems to play a major role in these patients. 

We also know from medical research that simply avoiding dairy if you have Hashimoto’s is often enough to IMPROVE your thyroid function without any other changes. 

Again, imagine taking a medication designed to help improve your thyroid which also contains an ingredient that is known to cause damage to your thyroid gland as well. 

Seems counterproductive, right?

This problem used to be isolated to levothyroxine and Synthroid but now extends to NDT formulations. 

Does Nature-Throid Still Work? 

Does all of this mean that you shouldn’t use Nature Throid or WP thyroid anymore?

Not necessarily, but it’s definitely something that you should consider before you jump into using it or before you try and swap medications. 

The last thing you would want to do is pressure your doctor to switch you from levothyroxine to Nature throid only to find out that it makes you worse off. 

Having said that, just because it contains lactose monohydrate does not mean that it will not work for you at all. 

Even if you have lactose intolerance AND Hashimoto’s thyroiditis, doesn’t guarantee that you will react negatively to lactose or that it will cause major problems for you. 

I know a number of patients who still do quite well on both formulations even with the lactose. 

Intolerance to medications of this type exists on a spectrum where some people are hit much harder than others. 

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So you might be someone who is negatively impacted by lactose but where the positive changes outweigh the small negative changes that you see. 

Because of this, you’ll want to assess your ability to use either on a case-by-case basis. 

But now with the addition of lactose to both of these formulations, it’s hard to recommend either as a preferred NDT formulation. 

Hopefully, the USP will change the formula for Thyroid USP and exclude the lactose portion in the future. 

What this means for you: 

There are fewer and fewer “clean” thyroid medications available on the market. 

And by clean I am referring to medications that contain ONLY the active thyroid hormones with as few fillers as possible. 

Right now, it looks like the cleanest thyroid medication on the market is Tirosint-Sol (which is a T4-only thyroid medication) which contains only 3 ingredients (1 active and 2 inactive). 

We are coming to a point where it may make more sense to start with compounded T4 and T3 medications instead of starting with NDT medications directly. 

I’m not sure we have quite reached this point, but that would be a major shift for all thyroid patients. 

Again, this doesn’t mean that these medications are useless but it does mean that you should be aware that they might cause problems because of their inactive ingredients. 

Now I want to hear from you:

Are you someone who is currently using Nature Throid or WP Thyroid (WP thyroid is more difficult to get but some people are still on it)?

Have you noticed any changes in terms of how it impacts your body?

Have you been constant or stable on your current dose without the need to change? 

Are you someone who knows that you react negatively to lactose?

Leave your questions or comments below! 

Scientific References

#1. https://getrealthyroid.com/assets/docs/Nature-Throid-Prescribing-Information.pdf

#2. https://getrealthyroid.com/assets/docs/WP-Thyroid-Prescribing-Information.pdf

#3. https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/021402s017lbl.pdf

#4. https://ghr.nlm.nih.gov/condition/lactose-intolerance#statistics

#5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586575/