Cytomel is the brand and trade name for Liothyronine Sodium, which is T3.
Liothyronine Sodium is a synthetic variant of the body’s own thyroid hormone.
The human body’s natural, endogenous thyroid hormone is actually known as Triiodothyronine, which is different from Liothyronine Sodium.
Liothyronine is the L-isomer of Triiodothyronine.
Liothyronine and Triiodothyronine are nearly identical to one another; however, Liothyronine is a more potent variant and is also more readily absorbed orally, which led to its development into prescription drugs and preparations known as Cytomel, Thyromel, Thyronamine, and others.
In medical and clinical settings, Cytomel (T3) is used to treat hypothyroidism, a condition where the thyroid gland fails to secrete adequate levels of thyroid hormones for proper bodily function.
Such cases of hypothyroidism are typically diagnosed via blood tests that analyze the serum hormone profile of thyroid hormones (T3, T4, and TSH, which is Thyroid-Stimulating Hormone).
Hypothyroidism is accompanied by various symptoms such as lack of energy, lethargy, increased weight and fat gain, hair loss, and changes in skin color and texture.
T3 is the primary thyroid hormone used by the body.
Unfortunately, T3 is one of those compounds around which a lot of mystique, rumors, and falsehoods have spread over the years in the bodybuilding and athletic communities regarding its function, uses, and how it should be used.
As a result, many individuals in the anabolic steroid-using community have developed a fear of T3, to the point where even the mention of its use makes them cringe.
This profile will correct these misconceptions and clarify the common misunderstandings surrounding Cytomel.
T3 was originally manufactured as a pharmaceutical drug from extracts derived from the thyroid gland.
This is how many hormonal pharmaceuticals began, originating from the endocrine glands of animals and human cadavers.
The first use of thyroid extract was in 1891 on a patient suffering from myxedema, a skin condition resulting from hypothyroidism [1].
Thyroid hormones were among the first hormonal pharmaceuticals used in the field of endocrinology and for the treatment of various disorders and diseases.
The initial thyroid extracts contained not only T3 but also T4, and these extracts were utilized in medicine for over 60 years.
In the 1950s, methods were developed to create thyroid hormones synthetically, which led to the phasing out of the previously used thyroid extracts.
The two most widely used synthetic thyroid hormones today are Liothyronine Sodium (T3) and Levothyroxine Sodium (T4), used extensively not only in the United States but throughout the world.
In the United States specifically, Cytomel is the most widely used and most well-known brand name for T3.
Like many other bodybuilding aids, T3 is widely available around the world, with very few or no laws governing its sale, distribution, purchase, or use in most countries.
It is manufactured by dozens of pharmaceutical companies worldwide under various brands and trade names, and there are also numerous generic T3 products available.
Given the vast availability and manufacturing of this product, it is not uncommon for the dosages of T3 to vary significantly from one product to another.
For example, T3 is commonly available in concentrations ranging from 5 mcg, 25 mcg, and up to 50 mcg tablets.
Cytomel (T3) Chemical Characteristics
T3 (Liothyronine Sodium) is a synthetic variant of the thyroid hormone Triiodothyronine.
Cytomel (T3) Properties
In the body, T3 serves the function of regulating how various nutrients are absorbed into the cells and the mitochondria of the cells so that they can be effectively utilized for energy production and consumption [2] [3].
The mitochondria in every cell of our body utilize carbohydrates (primarily), fats, and even proteins to produce a source of energy known as ATP (Adenosine Triphosphate).
Increasing the intake of T3 will result in an increased production of ATP, thereby increasing the consumption of energy in the form of fats, carbohydrates, and proteins.
Therefore, if one consumes too much T3 without the use of anabolic steroids, muscle loss can occur.
In the bodybuilding and athletic communities, the appeal for using T3 as a physique and/or performance-enhancing drug lies in its ability to markedly increase the body’s metabolism in order to metabolize body fat at a much faster rate.
T3 has traditionally been utilized during cutting, dieting, and/or pre-contest training phases, as the universal goal of such phases is the reduction of body fat, but it has recently gained popularity as a useful agent during bulk and mass-gaining training phases (usually alongside anabolic steroids) in order to process nutrients more efficiently or to keep body fat levels low during periods of high caloric intake.
Because Cytomel (T3) has such an overall large impact on the body’s metabolism, it is generally used in conjunction with anabolic steroids.
It is very important to understand that T3 possesses indiscriminate metabolism-increasing properties, increasing the metabolism of fats, carbohydrates, and proteins all equally.
Therefore, beyond a certain dosage of T3, the increased protein turnover increases the risk of muscle loss.
The method by which this muscle loss from T3 can be prevented is through the use of anabolic steroids and a properly regulated diet, due to the nitrogen-retaining and protein-sparing properties of anabolic steroids.
In addition, Cytomel (T3) is very often taken alongside other fat loss agents because it exhibits synergistic effects with them, increasing the overall effect.
These include Ephedrine, Clenbuterol, Albuterol, Human Growth Hormone (HGH), and other fat burners.
The combination of T3 with anabolic steroids and other fat-burning agents, and the possible interactions between them, will be covered in more detail in the Cytomel (T3) Dosage and Cytomel (T3) Cycles sections of this profile.
Liothyronine Sodium (aka Cytomel, T3, Thyronamine, Thyromel, Thyroid Hormone)
| Chemical Name | sodium (S)-2-amino-3-[4-(4-hydroxy-3-iodophenoxy)-3,5-diiodophenyl]propanoate |
| Molecular Weight | 672.96 g/mol |
| Formula | C15H11I3NNaO4 |
| Manufacturer | ICI |
| Half-Life | 2.5 days |
| Detection Time | Undetectable by urinalysis |
| Anabolic Rating | N/A |
| Androgenic Rating | N/A |
T3 References
[1] The emergence of endocrinology. Welbourn RB. Gesnerus. 1992;49 Pt 2:137-50.
[2] Human Anatomy and Physiology, 6th Edition. John w. Hole jr.
[3] Physicians’ Desk Reference #9
