Liothyronine and Weight Gain: What you need to know
To explain all that you need to know about liothyronine and weight gain, it is first necessary to understand a little about the two thyroid hormones and how they work.
Introducing T3 and T4
The human body, when working optimally, produces very carefully measured amounts of T3 and T4 thyroid hormones. T3 is the active version of the hormone, described as being three or four times more powerful than T4, while T4, the inactive version, is only used when T3 levels fall too low. But being inactive, T4 must be transformed in order to become active – and it is transformed into T3. When the thyroid is functioning perfectly, this all happens automatically, with the body carefully calibrating the levels of hormone in the blood and transforming T4 as it needs it, and together the two hormones work to keep our bodies warm enough, metabolising our food correctly and, in short, functioning properly and appropriately.
When It All Goes Wrong
However, occasionally, the thyroid begins to malfunction and this means that the levels of T3 and T4 become too high or fall too low. These conditions are called hyperthyroidism and hypothyroidism respectively and they are, essentially, symptoms rather than standalone diseases, that is to say, an illness or happenstance causes the fluctuations of thyroid hormone. These underlying causes can be from a genetic condition, a deficiency of some kind, or even a cancer – and surprisingly, despite sounding like the scariest diagnosis, thyroid cancer is the only condition from which you can, in theory, be cured – will all the others, the issue can be treated, but treatment will almost certainly continue for the whole of your life.
And this is where liothyronine (read more about it in this Liothyronine T3 guide) comes in.
Hyperthyroidism, when the thyroid produces too much hormone, can only be treated by turning it into hypothyroidism, by dramatically reducing the function of the thyroid. Sometimes this can mean removing the whole thyroid, at other times just parts of it.
Once the patient has hypothyroidism, their medical team will begin to work towards finding their ideal levels of thyroid hormone, and because these levels vary from person to person and are minutely graduated (a tiny amount more or less can have a huge effect on the patient) this can be something of a time trial, as the patient and doctor work together to work out the perfect dose for that patient.
Side Effect on Weight
One of the symptoms of a sluggish thyroid can be weight gain: beginning treatment with liothyronine can cause this excess weight to be lost, almost effortlessly. And it can be tempting to increase the dose of liothyronine in order to lose a little more weight, because who wouldn't want to be a bit slimmer? But this is strongly advised against. Because the hormone is so powerful when it is activated, increasing the dose, even by a seemingly small amount – say one-quarter of a tiny pill – can bring you closer to a toxic dosage, which can lead to the symptoms of hyperthyroidism and even build up into thyroid storm, which is a severe, sudden-onset crisis which can have long-lasting consequences on your body – or even result in death.
To summarise: while liothyronine might well help you to lose weight, it is absolutely never to be considered as a weight-loss or obesity treatment because it is simply too dangerous to your health. It is also simply not effective as a weight-loss treatment for weight gained through other causes than thyroid deficiency, making the ideal doubly unwise.