Cytomel T3 Side EffectsApril 17, 2022
L-triiodothyronine (T3) has previously been shown to cause rapid-acting, depolarization-inducing 45Ca and [acid release from rat brain 3H-gammaaminobutyric acid synaptosomes at low nanomolar concentrations consistent with those reported for whole brain. The physiological and psychological significance of these nonnuclear T3 mediators remains unclear, in part because the specific mechanisms and occurrence of T3 in plague areas have not been demonstrated. Isotopic studies showing that l-tetrahodothyronine (T4) and T3 are concentrated in synaptosomes and that T4 is deiodinated to T3 have shown that endogenous T3 concentrations are probably much higher in neural roots than in other parts of the brain. In the present study, we have confirmed that endogenous T3 concentrations in nerve roots are at least eight parts higher and may be up to 60 parts higher than in the whole brain. More importantly, we have shown that both 125I-labeled T3 and endogenous T3, but not 125I-T4 or endogenous T4, are released from depolarized synaptosomes mainly by a Ca2+-dependent process. This indicates a mechanism of upregulation of T3 levels in synapses, where hincret may interact with pre- and postsynaptic binding (or sensing) sites, and suggests that peripheral T3 hincret may be a neurotransmitter.
Because of the short half-life of T3, divided doses are preferable to a single dose unless the total daily dose is low. For example, a dose of 12.5 mcg/day would be better taken as a single dose in the morning, but for a dose of 50 mcg/day, it would be better to divide the daily amount into three or four doses rather than taking the entire amount at once.
After prolonged use of T3 as a suppressive dose, natural production continues to be suppressed for some time after T3 is discontinued. In general, the duration seems to be related to the duration of consumption. With short-term use, there is usually no significant functional impairment after one cycle, but with longer cycles, the duration of functional impairment can be measured for about 6 weeks in some cases. The article “Rescue of pituitary thyrotropic verbal function after dilution of enhanced thyroid suppression therapy” provides an example of the difficulties that may be encountered in recording good thyroid performance after prolonged thyroid verbal use.
Although all questions in this study yielded “normal” thyroid production, as is common in bodybuilding practice, “normal” proved to be the lower end of the normal range, about 40 mcg/dl with total serum T4 and serum T3 of about 80 ng/dl. These do not want levels one, and low enough that metabolism was damaged.
A high dose of T3, usually starting at 75 mcg/d but in some cases not at 100 mcg/d, does not necessarily cause tachycardia (increase in heart rate) and muscle weakness, but may be catabolic or at least reduce assimilation. High doses of anabolic steroids, of course, clone the latter effect. Very high T3 concentrations are dangerous to the heart.
The following is a list of possible side effects that may be caused by components of Cytomel tablets. This list does not claim to be definitive. The side effects listed have been reported in the past, but are not always recorded when the product is used. Some of the side effects listed may occur very rarely but are very serious. If you experience side effects, you should seek immediate medical attention. Especially if the side effects are observed over a long period of time.
pain or irritation at the injection site
If you notice side effects not listed above, contact your doctor. You may also report any side effects you notice to your local food and drug administration.
Before you start taking this medicine, tell your doctor about all medicines you are already taking, dietary supplements (e.g., vitamins, natural products, etc.), allergies, existing medical conditions, and current health conditions (e.g., pregnancy, upcoming surgery, etc.). The side effects of a medicine may be more pronounced in certain body conditions.
Take the medicine as directed by your doctor or follow the instructions for use that come with the medicine. The dose of the medicine depends on your condition. If your condition does not change or if it worsens, tell your doctor. The following are important things to discuss with your doctor.
You are pregnant, planning a pregnancy or breastfeeding.
Check your blood sugar regularly
Thyroid hormone preparations are natural or synthetic preparations containing sodium tetraiodothyronine (T4, levothyroxine) or sodium triiodothyronine (T3, liothyronine) or both. T4 and T3 are produced in the human thyroid gland by iodination and binding of the amino acid tyrosine. T4 contains four iodine atoms and is produced by binding two molecules of diiodothyrosine (DIT). T3 contains three iodine atoms and is formed by the binding of one molecule of DIT and one molecule of monoiodotyrosine (MIT). Both hormones are stored in the thyroid colloid as thyroglobulin.
Thyroid hormone preparations fall into two categories: natural hormone preparations derived from the thyroid gland of animals and synthetic preparations. Natural products include dried thyroid gland and thyroglobulin. Dried thyroid is derived from domestic animals eaten by humans (bovine or porcine thyroid) and thyroglobulin is derived from porcine thyroid. The United States Pharmacopoeia (USP) has standardised the total iodine content of natural products. Thyroid pharmacopoeia contains a minimum (NLT) of 0,17 % and a maximum (NMT) of 0,23 % of iodine, and thyroglobulin contains a minimum (NLT) of 0,7 % of organically bound iodine. The iodine content is only an indirect indicator of the actual biological activity of hormones.
Cytomel (liothyronine sodium) tablets contain liothyronine (L-triiodothyronine or LT3), a synthetic form of the natural thyroid hormone, available as the sodium salt.