Transcription
Levothyroxine is by far the most commonly prescribed medication used to treat hypothyroidism, and most thyroid patients who take it have no idea of the problems that it can cause. This is probably why thyroid patients who take it rated a 5.1 out of 10 on average, and why so many prefer to take other medications instead, like Armour Thyroid and liothyronine. While it still can be effective for many, if you are someone who is taking it, you should be aware of these alarming side effects.
Number one, weight gain. Most thyroid patients believe that if they take thyroid medication, they should actually experience weight loss. But unfortunately, that's not always the case. Instead, what many thyroid patients experience is that as they take levothyroxine, they see their weight continue to climb upwards. And this is not the minority of patients either. It's hard to assess exactly how many thyroid patients experience weight gain while taking levothyroxine, but based on available numbers, it's probably in the range of 30 to 40%. And if you are somebody who has experienced weight gain while taking levothyroxine, please do leave a comment below so other people can get an idea of how common it really is.
But getting back to the topic, why is it that taking levothyroxine is associated with weight gain? The exact cause isn't known, but here are a few theories. The first is that the people who are taking it probably are not taking enough of it. In this setting, it's not a side effect of the medication itself. Instead, it's caused by an inadequate level of treatment, which allows for your low thyroid symptoms to persist. In this setting, the thyroid patients who experience weight gain while taking it are incorrectly attributing their weight gain to the medication when it's really related to their thyroid symptoms. That said, there are still people who do experience weight gain directly related to the medication itself. And in this setting, the mechanism of action is related to its suppressive effects on your own thyroid gland. But when you take levothyroxine, you are trading out a T4 only thyroid hormone for the natural production of both T3 and T4 that would have occurred otherwise. But if your body is unable to take that T4 that comes from the medication itself and convert it into T3 thyroid hormone, which is the active form, then you may be filling your body with inactive T4 thyroid hormone that can't really be used to increase your metabolism or resolve your symptoms. This malfunction of the thyroid conversion process is probably one of the main reasons that thyroid patients experience weight gain while taking levothyroxine and other T4 only thyroid medications. The good news is that this is a completely solvable problem, and it's the main reason why I'm always recommending that thyroid patients take a full suite of thyroid hormones, including T4, T3, and T2. For perspective, if you are taking levothyroxine, you are only getting one of those three thyroid hormones, and it's the least active and least powerful of them all.
Number two is that levothyroxine may cause an increased risk of cancer. This one is probably the most alarming on this list, and it's the one that gets everyone riled up. But before you get upset, here are the facts. Several large-scale studies, and I'm talking big, on the order of hundreds of thousands of people, have shown that there is a connection between cancer and levothyroxine use. I will give you my own thoughts on this in just a minute, but stay with me so we can put everything on the table. One study looked at 600,000 patients taking levothyroxine and compared them to 400,000 healthy people who didn't have a thyroid problem. They did this for 10 years, and they found that the people who were taking levothyroxine had about a 50% increased risk of cancer at several different sites. While this may be concerning, there are a few things to know before you start to get stressed out. The first is that all of these studies do not prove causation. They only show correlation. So, it may very well be the case that thyroid patients have a higher risk of developing cancer regardless of whether or not they are taking thyroid medication. But one thing is for sure, this is something that needs to be evaluated further and fully fleshed out. Because if it is the case that taking levothyroxine does increase your risk of cancer, this is something that everyone who is taking it should be aware of.
If you're asking me, I do not believe that levothyroxine use increases cancer risk by itself. Instead, here's what I think is probably happening in most people when thyroid patients take levothyroxine. Because of the way that doctors prescribe and manage levothyroxine dosing using the TSH, it's my belief that most people who take it are being underdosed. As a result, they are in a state of constant low thyroid function that is not comparable to someone who has a healthy functioning thyroid gland. And it's this state of lower than normal T4 and T3 that leads to the increased risk of cancer that we're probably seeing in some of these studies. In this scenario, the link to cancer is related to the levothyroxine dose but not the medication itself, because I believe if the medication were to be dosed appropriately in the majority of individuals, that this risk would disappear. But this is my own personal theory, and we need more data to confirm it. The good news is that up to 30% of thyroid patients who are taking levothyroxine may not even need to be on it at all. So don't get depressed into thinking that you must take it for life just because you started it, as that may not be the case.
Number three is hair loss. Hair loss is another tricky side effect associated with levothyroxine use, and it can be caused in multiple different ways. The first is that levothyroxine use itself can cause hair loss regardless of how much you are taking. The second is that it may appear to cause hair loss if you are being underdosed. And the third is that it may appear to cause hair loss if you are being overdosed. Too little keeps you in a state of hypothyroidism, and hair loss is associated with that state. And too much puts you in a state of hyperthyroidism, and hair loss is also associated with this state. The hard part with levothyroxine-related hair loss is figuring out which category you fit into. But the good news is that all of them are treatable. If, for instance, your hair loss is related to the medication itself, then all you need to do is switch to another medication like Tyrat, Levoxyl, or Armour Thyroid, or any of the other ones. If, on the other hand, it's related to an insufficient dose, all you need to do is bump up your dose. And if it's related to too much levothyroxine, all you need to do is drop down your dose. Either way, don't stress too much about this side effect because each of these is treatable and manageable.
Number four is the risk of dementia. Some new research is showing that there may be a link between levothyroxine use and cognitive decline, including dementia. It's important to note that this side effect seems to be more common in people who are older. And while we don't completely understand the exact relationship between these two things, here's what we do know. One large-scale study of over 15,000 people found that those who had hypothyroidism had about an 81% increased risk of developing dementia compared to healthy people. This is concerning by itself, but what's even more concerning is that this study showed if you were someone who had hypothyroidism and you were taking a thyroid medication, your risk increased by more than threefold. This one study seems to suggest that there is, in fact, a connection between dementia and the use of thyroid medication. Not much else is known except what I've shared here, but my own personal suspicion is that this is another situation in which these side effects probably have to do with the people who are taking it and receiving an insufficient dose. In this way, it's probably not the medication causing the problem. But what makes this connection even more confusing is the fact that some studies show that taking thyroid medication actually reduces your risk of dementia. As a result, it's hard to discern exactly what's going on here, but I still think this is something that every thyroid patient should be aware of.
Number five are bone density concerns. This is another concerning side effect, especially for women who have hypothyroidism and who are also post-menopausal. It's long been known that there is a connection between altered thyroid states and bone loss. But now, it's looking like the use of levothyroxine may make this problem worse. Here's what I mean. One study of 81 thyroid patients and over 364 controls showed that even with a completely normal TSH, patients taking levothyroxine experienced more bone loss compared to healthy individuals. The big concern here is that this effect still existed even after controlling for TSH level, age, and gender. This is another one of those situations in which it's hard to pinpoint the exact mechanism, but I still think it's something that every woman, especially, should be aware of.
Does all of this mean that you need to panic if you're taking levothyroxine? Not necessarily. And here's why. The first is that in many of these situations, we don't know if the side effect that we're talking about is directly related to the medication or due to the disordered thyroid state. Second, and perhaps more importantly, is the fact that up to 30% of patients taking levothyroxine may be able to stop taking it. And this represents a huge number of you listening to this video right now. To make things even better, there are things that you can be doing right now to help facilitate this process. And one of those is the use of supplements. If you want to see a list of supplements that may help you get off your thyroid medication, then check out this video.