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Ask Dr. Mike: Low Testosterone Levels & Reverse T3 Testing

Here you'll find the answers to a wealth of health and wellness questions posed by Healthy Talk fans. Listen in because what you know helps ensure healthy choices you can live with. Today on Healthy Talk, you wanted to know:

My total testosterone is low, but my free testosterone is high. Am I missing something?

Having low testosterone just means you're not producing as much testosterone as you used to. However, the testosterone you are producing might be releasing in your body's tissues (like fat cells) and turn into estrogen, or DHT.

Dr. Mike suggests getting another test just to make sure there wasn't an error. You may also want to look at your free testosterone level and sex hormone-binding globulin (SHBG).

I've been on thyroid medication for two years but I still have constipation and fatigue. Should I check reverse T3?

Dr. Mike thinks you might want to consider looking into to T3. A test called reverse T3 may offer some insight to why some people with hypothyroid remain symptomatic even while taking medication.

If you have a health question or concern, Dr. Mike encourages you to write him at This email address is being protected from spambots. You need JavaScript enabled to view it. or call in, toll-free, to the LIVE radio show (1.844.305.7800) so he can provide you with support and helpful advice.

RadioMD Presents:Healthy Talk | Original Air Date: April 30, 2015
Host: Michael Smith, MD

RadioMD. It's time to ask Dr. Mike. Do you have a question about your health? Dr. Mike can answer your questions. Just email This email address is being protected from spambots. You need JavaScript enabled to view it. or call now: 877-711-5211. The lines are open.

DR MIKE: Gary G. sent me an email to This email address is being protected from spambots. You need JavaScript enabled to view it. :

"My total testosterone is low but my free T (free testosterone) is high. How could that be? Am I missing something? Thanks."

Great. Gary this is a good question. I think more and more of us, men and women, are checking our hormones. As a longevity doctor, healthy longevity doctor, hormones are definitely an important part of the tools I use not only in my own body but in other people to help them live healthier and longer. And we're just seeing more and more people testing hormones; seeing where they're at. So, I think this is a great opportunity to talk about what might be going on here because this is something common. Well, I don't want to say it's common but it's not uncommon. Gary, it's not uncommon that we see this. So, your total testosterone is low.

Okay, so that one is easy to explain. Your testicles are not producing as much testosterone. There's the type of cell in the testicle called the Leydig cell. They just become dysfunctional. Many of them die off. You're just not producing as much testosterone. That's number one. Then, of course, the testosterone you are producing, once it gets out in your system, it gets into certain tissue like fat, it can turn into estrogen more. Other types of cells like muscles and stuff like that, even in hair follicles, it can turn into a more potent form of testosterone called DHT. So, your body's not making as much testosterone and what you are making more of, it is converted into estrogens and DHT.

So, that's why total amount goes down. And in most cases, Gary, most men that's followed by a drop in free testosterone as well but in your case your free testosterone, I'm assuming, has remained normal or gone up a little bit. And so the first thing that I would do is, I would re-test. I would make sure that this isn't a lab error.

I mean, technically speaking if total testosterone drops, free testosterone should drop as well. So, that might be the first thing is just double check. Make sure we're looking at some real numbers here and if you do that and sure enough total is down, and free is remaining the same or a little higher, okay, well then, we've got to explain what could be going on. Well, one of the things that we have discovered over the past few years since more people are checking their hormones is there's a—these steroid hormones, by the way, Gary, are fat based. They come from cholesterol. Cholesterol makes pregnenolone, pregnenolone then makes all these steroid hormones: progesterone, DHEA, testosterone, estrogen. So, these are fat-based, cholesterol-based compounds.

And they have to travel in your watery blood stream, so they need a carrier molecule to do that and that carrier molecule is kind of like the truck that can swim in the bloodstream and inside the truck is the steroid hormones and other types of fats called a sex hormone binding globulin. It's just a fancy way of saying a protein that carries the testosterone. And what we have found as men get older, in most cases--I'm going to give you the common scenario. In most cases, as the testosterone levels drop in a weird way for most men, the sex hormone binding globulin goes up. Sounds weird but it just—for some reason we don't make as much of the product but we make more of the trucks to carry the product.

And so, when testosterone levels drop, we can often see a huge drop in free testosterone because you've got so many trucks out there that are binding to the testosterone that are holding onto it that are not releasing it to become free testosterone in the tissue. So, the normal scenario is as a man gets older total testosterone drops, free testosterone really comes down and sex hormone binding globulin actually goes up a little bit. It's kind of weird. That's the common scenario but we do, now that we're checking enough labs, we are seeing that there are some guys out there, and women included in this, do the opposite.

As total testosterone drops they actually make less sex hormone binding globulin allowing more of the testosterone to be released to the tissue and become free. I don't know if I have an explanation. I'm just telling you what we see in the labs. You might just be one of those people, Gary, who, for whatever reason, your sex hormone binding globulin, the truck that carries the testosterone, you're not making as much of it and it's just releasing the testosterone more readily into the tissue to maintain a higher level of free testosterone. That's probably more ideal.

So, your body is actually a little more optimized for all this, Gary. I can tell you in my personal experience I was not like you. I was more of the average guy. My body was not optimized for this. I lost some testosterone, sex hormone binding globulin went up and I lost a lot of free testosterone because of that. But your body is actually handling the loss of testosterone a little bit better. I would expect your sex hormone binding globulin.

Gary, is probably a little bit lower than mine was. That might explain why you're able to maintain a more optimal, ideal level of free testosterone. But, again, that would be uncommon, Gary. We do see it so you might want to first just check again. Repeat the labs and if that's the case, that's awesome. You're free.

So, I would, for someone like you, it's really more important to look at that free testosterone and as long as that's in a nice optimal range for guys, you may not have to do anything at this point. And just ask your doctor to check the sex hormone binding globulin as well. Now, for the guys that are more like me, I'm going to change the scenario here.

So, I'm not really speaking to Gary. Now I'm talking to myself. What about that scenario which is more common where you lose testosterone, your sex hormone binding globulin goes up, free testosterone really crashes. What can you do to help get some of that testosterone you are making off the truck? The sex hormone binding globulin. What can you do? There isn't a lot of good research here but things like nettle's root, stinging nettle's root has been shown to help, cruciferous vegetable extracts have been shown to help to maybe offload some of that free testosterone.

Great question, Gary. Thank you. I could talk a long time about hormones.

As a matter of fact, we're going to talk about hormones again. This time thyroid. This comes from Elizabeth who read about reverse T3 at Life Extension, so she says—or she writes:

"I've been on thyroid medication for two years and it's helped a little bit. I still have constipation and fatigue. Should I check a reverse T3, something I read about at Life Extension. Thanks, Elizabeth."

Yes. I think you're right on so let's explain what's happening here. The thyroid gland, which is in the neck, mostly produces what is called T4 and T4 then travels throughout the body, gets into the tissue and it converts into the more active form of thyroid hormone called T3. And T3 is really what gives you the thyroid effect in the tissue. I mean T4 helps a little bit but the main job of T4 is just to get to the tissue: muscles, brain, heart, whatever, gut, nerves.

And then once it's there, it turns into T3 which is really the workhorse of the hormone. So, what happens in many cases when we're not producing the T4, we have hypothyroid. We have to go on medication. And most of the medications or the most common medication is called Synthroid. That's what most people are on and it's only T4. And that T4 gets to the tissue and for a variety or reasons, it doesn't convert into T3.

So, people still have symptoms of low thyroid. That's probably why it's better, Elizabeth, to do some of the more natural thyroid product, desiccated pig for instance, there's Nature-Thyroid and there's different ones out there but these are medications that provide T4 and T3, so that might help right there. But the other thing is, if you want, you can check this thing called reverse T3.

What happens is when T4 does get...Let's say it's Synthroid, your medication which is T4, gets to the tissue and instead of turning into T3, it turns into this thing called reverse T3. It's basically kind of like the mirror image of T3, but it doesn't work. It's non-functional. So, you might want to check that. If reverse T3 is high, then it's a sign that your T4 is not converting properly and one of the most common reasons for that is stress, cortisol. So, do something like DHEA to bring cortisol levels down.

This is Healthy Talk on RadioMD. I'm Dr. Mike. Stay well.