Levothyroxine Dosage Guide: Are you on the Right Dose?
Are you on the right Dosage of Levothyroxine for YOUR body?
If you are on Levothyroxine and NOT feeling better then one or more of these things might be happening to you:
- You are not on a high enough dose
- You are on the WRONG type of T4 thyroid medication
- You are not absorbing thyroid hormone correctly
- You are not getting enough T3 thyroid hormone
But the main question is:
How do you know which category you fall into?
That's where I come in...
Sit back and enjoy this article because we are going to dive in and talk about everything you need to know about Levothyroxine and how to find the right dose for your body:
Are you on Levothyroxine and Still having Hypothyroid Symptoms?
This is NOT a good sign.
Levothyroxine is a form of thyroid hormone replacement, so shouldn't your thyroid symptoms at least go DOWN while taking it?
The answer is YES!
What do I mean by symptoms?
These are the most common symptoms of hypothyroidism that I see in my patients:
- Fatigue or exhaustion even after sleeping 8+ hours at night
- Weight gain or weight loss resistance (no matter how much you exercise or how little you eat)
- Depression, anxiety or mood swings
- Problems with PMS, menstrual cycle or low sex drive
- Chronic pain in the muscles and joints
- Cold extremities (hands and feet)
- Chronic constipation
THESE are the symptoms I'm talking about - they should be going away or gone while taking thyroid medication like Levothyroxine or Synthroid.
But I'm guessing you are still experiencing these symptoms which is why you are here...
And you might be frustrated because your Doctor keeps telling you that your labs are fine and yet you still feel like crap...
And you might even be wondering if it's all in your head...
It definitely is NOT.
I'm here to tell you that it is possible to go on thyroid medication and reduce or eliminate your symptoms of hypothyroidism.
But it takes a different approach...
One that takes into account MORE than just your lab tests (though these are important and we will talk about them later).
The truth is that most hypothyroid patients are either being under treated or treated with the wrong thyroid medication.
How to Determine if your T4 Dose is High Enough for Your Body
Each one of you has a different demand for thyroid hormone in your body...
The more stress you are under, the more inflammation you have, the sicker you are the HIGHER your demand for thyroid hormone becomes.
So why do we treat EVERY patient the exact same?
Do you think an 80 year old patient needs the same amount of thyroid hormone as a young woman in her 20's or 30's?
The answer is obviously NO.
So why do we treat each patient the exact same way?
Unfortunately most Doctors base all of their treatment recommendations, including dosage of thyroid hormone on lab tests.
And unfortunately thyroid lab tests are notoriously inaccurate due to a number of reasons including tissue sensitivity to thyroid hormone and different deiodinases in different tissues.
So how do you find your dose?
The BEST way is to use a combination of tests to put the puzzle together...
1. Check your metabolism
Thyroid helps control your metabolism, so shouldn't it go up if you replace the lost thyroid hormone in your body?
The answer is YES!
So it makes sense to check your metabolism to see it increase with thyroid hormone, right?
But the question is:
How do you do it?
A quick and easy way to test your metabolism is to check your basal body temperature each morning.
The more energy your body produces the higher your body temp goes and this can be indirectly used as a measure of metabolism.
No, it's not a perfect test! Medications and ovulation can interfere, but it is better than nothing so I do recommend you track it.
All you need is a thermometer and a pen and paper by your bed to measure it each morning.
I recommend checking it FIRST thing in the morning and keeping a record.
As you take thyroid hormone your body temperature should increase over time, but it may take up to 1-2 months to notice the difference.
Unfortunately for many patients Levothyroxine does NOT result in an increase in metabolism due to conversion issues and if that is happening to you it may be an indication that you need T3 added to your regimen.
2. Follow the labs (including free thyroid hormones)
I just told you that labs aren't the best way to measure thyroid hormone and that's true... BUT, that doesn't mean they are useless.
I recommend following your free thyroid levels, NOT just your TSH.
As you take Levothyroxine, Synthroid or T4 medication your free T4 levels SHOULD increase.
And if you don't have a problem with thyroid conversion, then your free T3 levels should also increase.
A word of caution though:
If your free T4 increases and your free T3 does not, this is a bad sign.
It means your body may be converting T4 into reverse T3 and making your symptoms worse (we will talk more about this later).
3. Monitor your symptoms
And last but certainly not least, make sure to monitor you symptoms!
If that weight gain, hair loss or fatigue is due to low thyroid levels then it SHOULD get better when you replace those levels.
If your symptoms do not go away then you either need a different type of thyroid medication (more on that below) or your symptoms are from SOMETHING else.
By using these 3 tests you can make sure you are being properly treated.
This method helps to prevent those patients who feel terrible but have completely "normal" lab tests from being ignored.
Levothyroxine VS Armour Thyroid VS Liothyronine
As you probably know there are several different types of thyroid hormone replacement that your Doctor could use for you.
Unfortunately most Doctors give out the same medication: Levothyroxine or Synthroid.
Both of these medications contain the inactive thyroid hormone T4 and in order for it to be active in your body it must be converted to the active T3 thyroid hormone.
Many patients don't convert the thyroid hormone appropriately which can lead to a number of thyroid symptoms.
And that's where the other thyroid medications come in...
Most patients do MUCH better on a combination of T4 AND T3, not just T4 medication alone.
And I'm not just saying this from experience, most patients also agree that medications containing T3 are superior...
In clinical studies most patients prefer natural desiccated thyroid hormone (thyroid hormone that contains T3) over T4 medication alone.
In the study above it showed that patients on this medication had more weight loss and a better quality of life!
In my practice I've also found that most patients who switch from Levothyroxine to medications containing T3 do MUCH better.
They have more energy, less hair loss and more weight loss.
What to do if you have Hypothyroid Symptoms on Levothyroxine
So what should you do if you are taking levothyroxine or another T4 medication and your body temp is low, your heart rate is low and you are still symptomatic?
The good news is that there are several tips and tricks you can follow to make your current dose more effective.
Most problems from levothyroxine have to do with absorption.
Usually a reduction in the absorption rate due to various factors.
At best we absorb about 80% of thyroid hormone that we ingest.
But this number rapidly reduces in the setting of GI related problems, inflammation, low stomach acid and other GI problems.
Anyone who is suffering from constipation, gas/bloating, acid reflux, diarrhea, abdominal pain, gastric ulcers, low stomach acid, etc. will have a reduced absorption of their thyroid medication.
This is complicated further by other medications and supplements which may further reduce thyroid hormone absorption if not taken at the correct time.
So let's talk about how you can impact the absorption component and get more "bang" for your buck so to speak.
#1. Levothyroxine 50mcg tablet
The 50mcg tablet of Levothyroxine is better than other doses of levothyroxine.
Because each dose of levothyroxine is a different color and contains different inactive ingredients and fillers.
These fillers act to cause symptoms by themselves (which can be confused with hypothyroid symptoms), but they also reduce absorption and the effectiveness of thyroid hormone in your body.
The 50mcg tablet of Levothyroxine is special in that it is white and does NOT contain any fillers or additives when compared to the other dosages.
This presents a unique opportunity where you can switch your current dose of Levothyroxine to 50mcg increments to potentially benefit from this.
Let's say you are currently taking 150mcg of Levothyroxine.
You could easily switch to taking 3 of the 50mcg tablets of Levothyroxine which would be the same equivalent dose and get rid of all of the fillers/dyes in the process.
Something as simple as this change can actually improve how you are feeling.
Even better is that most physicians won't have a problem with switching your dose (but they may put up resistance to switching your medication entirely).
#2. Consider switching to Tirosint
What is Tirosint?
Tirosint is another T4 only thyroid medication.
It's special because it has the fewest inactive ingredients out of all thyroid medications.
It contains 3 inactive ingredients and 1 active ingredient (thyroid hormone).
This makes Tirosint very easy to absorb.
Many patients have reported an improvement (and reduction) in their symptoms simply from switching from Levothyroxine/Synthroid (generic versions) to Tirosint.
Tirosint is very well tolerated and may actually improve your symptoms.
The good news is that Tirosint is another T4 only thyroid medication which means that your physician shouldn't put up much resistance to switching your medication.
Like other forms of T4 thyroid medication the doses are equivalent.
Meaning if you are taking 100mcg of Levothyroxine you can switch to 100mcg of Tirosint.
I've gone as far as to say that many hypothyroid patients not doing well on levothyroxine should at least consider switching to Tirosint for a trial.
You can read about all of the potential benefits of Tirosint in this comprehensive post.
#3. Increasing absorption of thyroid hormone + When to take your thyroid hormone medication
If you are unable to switch to 50mcg increments of levothyroxine or if your provider isn't willing to switch you to Tirosint there are other steps you can take to improve absorption.
The first is to simply change the time of day that you can your thyroid medication.
Studies have shown that taking your thyroid medication at night can actually increase serum thyroid levels.
This is most likely due the speed of your GI tract at various times of the day.
In the morning your GI tract is sped up which will limit absorption of thyroid hormone.
At night your GI tract slows down which may allow for higher absorption.
In addition your cortisol levels peak at 8am in the morning (when most patients take thyroid hormone) which may also influence thyroid hormone metabolism.
It's certainly worth a discussion with your current physician to determine if taking Levothyroxine at night may help you.
The second option is to treat any GI related problem that may be limiting your absorption.
By addressing conditions such as low stomach acid, SIBO/SIFO (very common in hypothyroid patients) and other GI related problems you can actually increase thyroid hormone absorption.
Do you need T3 medication?
By now you might be asking, do I need to be on medication containing T3?
The answer really depends on you, but I can help you figure it out...
I've put together an image that helps patients determine which medication they would do best on:
In general patients who should consider using Natural Desiccated thyroid hormone or T3 containing medications include:
- Those who don't feel better on T4 only containing medications even after tracking their metabolism, symptoms and lab tests
- Those who have not lost weight on Levothyroxine or Synthroid
- Those who notice their symptoms getting WORSE despite increasing their dose of T4 medication
If you fall into any of the above categories then it would be worth talking to your Doctor about switching your medication to something that contains T3.
And don't sweat it if your Doctor isn't willing to use Natural Desiccated thyroid because he/she may be open to using Liothyronine instead.
Liothyronine or Cytomel both contain pure T3 medications and can simply be added to your current dose of Levothyroxine.
So let's say you are taking 100mcg of T4 and you aren't feeling well at all.
Instead of switching to 1-2 grains of NDT you can simply add 5-20mcg of liothyronine or cytomel to your current dose of levothyroxine.
That would make your dosing look like this:
- Levothyroxine 100mcg per day
- Liothyronine 10mcg taken twice per day for a total of 20mcg per day
This allows for roughly an 80/20 ratio of T4 to T3 which is similar to what the thyroid produces naturally.
Levothyroxine Dosage Chart and Comparison Table
So, what if your Doctor isn't willing to change medications or you really like being on Levothyroxine?
Then make sure you are on the right dose!
I usually recommend basing your dose off of the 3 step system I outlined above: Lab tests, symptoms and metabolism.
I usually recommend slowly increasing your dose of Levothyroxine by about 25mcg every 10-14 days.
A good starting dose would be 25mcg (I recommend using the 50mcg tab and cutting it in half), then slowly increasing your dose and rechecking labs every 4-6 weeks to follow free T3, free T4 and reverse T3 levels.
(This is the conversion chart that I recommend using which is different than from what most Doctors use)
Dosing varies quite a bit based on the person but a typical dose may range between 25mcg and 250mcg of Levothyroxine or Synthroid per day.
If you have continued to increase your dose beyond 150mcg and haven't noticed ANY improvement in your symptoms that is another sign that Levothyroxine may not be the best medication for you.
If your Doctor still isn't willing to trial NDT or T3 containing medications then you can also try other forms of T4 with less fillers like Tirosint and continue increasing your dose slowly over time.
If you are switching from T4 to another medication this comparison chart may be helpful:
This chart isn't perfect but it is a good starting place.
I find that the conversion from T4 to NDT or natural desiccated thyroid to be too low (meaning you usually need more NDT to make it equivalent to the T4 dosing).
In my personal experience 2 grains is closer to 100mcg of T4 than 1 grain, but it is important to start out slowly if you are switching medications because T3 can be VERY stimulating to some people.
How I start patients on Thyroid medication and how I use Levothyroxine in my Practice
In my practice I've found that about 5% of people do better on Levothyroxine or Synthroid over other forms of medications. *Note: nowadays I'm primarily using Tirosint for every patient taking T4 medication due to its superior absorption.
So, yes I still use this medication but not often.
The patients I've found that do best on T4 medications are those who are VERY sensitive to T3 containing medications, meaning they get palpitations or anxiety by taking it.
Or those patients who are great at converting T4 to T3, so patients with very few other medical conditions.
The vast majority of patients do much better on T3 containing medications.
The average dose I have patients on is anywhere between 50mcg and 150mcg.
Recap + Final thoughts
Believe it or not your dose of Levothyroxine depends on multiple variables, all of which need to be considered to help reduce symptoms and help you feel better.
Remember that Levothyroxine absorption plays a big role in how you may feel.
By switching your dosage to 50mcg increments of Levothyroxine or switching to Tirosint all together you may improve your thyroid hormones.
Another option is to consider changing the time to day that you take thyroid hormone.
Lastly, you should also consider treating any GI related problems that may be limiting your absorption as well.
If these options fail then you might consider the addition of T3 containing thyroid medications.
To get these medications you will need the assistance of a physician who is knowledgeable about thyroid function.
Now it's your turn
Are you on Levothyroxine and feeling good? Have you tried any other thyroid medication? Which worked well for you?
Leave your comments below!