Muscle Sport Magazine

CYTOMEL (Liothyronine Sodium)

By Leigh Penman – Cytomel is a synthetic form of the thyroid hormone tri-iodio-thyronine(T3). Thyroid hormones act as metabolic regulators in the body, with high levels of T3 leading to a significant increase in metabolic rate. This allows the user to burn more calories and, in turn, use the calories consumed in a more efficient manner. Bodybuilders favor the use of Cytomel during the final phases of contest preparation in order to assist in the removal of any remaining stubborn body fat. However, it has been speculated that by using the drug in this way you may not be receiving an optimum effect due to the fact that towards the end of your diet natural thyroid production will be reduced due to the cumulative effects of calorie restriction. The supposition being that using Cytomel in the final weeks will only bring thyroid production back to what is considered ‘normal’ for you and will not actually produce an effective increase. When you stop to think about it, this would be a reasonable argument for the inclusion of Cytomel at the onset of a contest diet in order to produce a significant increase in T3 levels.


An interesting property of Cytomel is its ability to up-regulate the beta-2 adrenenergic receptors in fat tissue. Since drugs such as Clenbuterol (also widely used in contest prep.) are known to down regulate these receptors, using Cytomel with Clenbuterol may assist in reversing this phenomenon and thus prolong the effectiveness of the Clenbuterol. Another argument for using the two compounds together would be the fact that Clenbuterol has a protein sparing effect, which helps to curtail the catabolic effects of Cytomel on muscle tissue. Due to the catabolic effect of Cytomel it is always recommended to take it with some kind of anabolic substance to prevent (or at least reduce) the loss of lean muscle tissue.


Due to the fact that Cytomel is an extremely powerful drug, it is always recommended to start by taking a low dose and then gradually increase this until you reach a dose that you are comfortable with. The length of time you should stay on each dose before increasing it should be at least 3-4 days, however the ideal amount of time before increasing doses would be 1-3 weeks. The doses should also be increased by no more than 12.5mg at a time to avoid shocking your thyroid too much. It is also recommended that you never go above 75-100mcg per day since by the time you reach the 50mcg mark some shutdown of natural thyroid production will be experienced. The effect Cytomel has on natural thyroid production also makes it extremely important that you never stop using this drug ‘cold turkey’ – which could cause a rebound effect where weight gain would be experienced as the thyroid tried to regain normal function. With this in mind, always reduce your intake of Cytomel gradually. This will allow your thyroid to slowly adjust to the loss of its ‘pharmaceutical assistant’ and smoothly transition back to normal (pre-drug) function.


There have been many scare stories in circulation regarding the use of Cytomel over the years. The main one being that if you take exogenous T3 your thyroid will be dependent on it for life, as it will be unable to function without it. The fact is that ANY substance you take to ‘assist’ your body to carry out a process it is used to executing on its own will lead to an impairment of the natural function once the ‘help’ has been removed. This impairment is usually temporary though and your body will re-adjust to the new situation and ‘normal service’ will be restored. This is why it is important to taper as it avoids shocking the system – which would occur if the drug were abruptly withdrawn.

Another speculation involving Cytomel is that it may actually enhance protein uptake in the muscles when used in the off-season in combination with anabolic steroids. This is based around the fact that supplemental T3 significantly enhances the uptake of nutrients into the mitochondria. However, T3 also increases their oxidation rate (the rate at which they are burned as energy) so it is more than likely that any increase in protein intake would be quickly burned as energy rather than stored in the muscle. As previously mentioned, the main reason for taking anabolic steroids when using Cytomel is to preserve muscle tissue, not to actually increase muscle growth.

At the end of the day, the main purpose of taking exogenous thyroid hormone is to accelerate the metabolism and speed up fat loss. Taken correctly, Cytomel executes this task flawlessly and, when taken in tandem with Clenbuterol, there is no better pre-contest fat loss cycle….end of story!

N.B Cytomel is available from

Leigh Penman began her writing career in 1980 when she started her own weekly music column in a Scottish newspaper. From there she went on to writing for all the major music publications in the UK at that time, including ‘Record Mirror’, ‘Sounds’, ‘New Musical Express’ and ‘Number One’. Her work included interview such celebrities as Madonna, Cher, Tina Turner and David Bowie.

The late 80’s saw her moving into writing for nutrition companies and eventually bodybuilding magazines. She rapidly gained a reputation as being one of the top female writers on the bodybuilding scene and was a contributing editor on ‘Muscle & Co’, ‘Bodybuilding Monthly’, ‘Strength Athlete’, ‘Health & Fitness’ and ‘Fit Body’. She was also a major contributor to the Arnold endorsed magazine ‘Bodypower’ –where she went on to establish the position of ‘Show business Editor’. In addition to this she held the position of Ladies Editor for ‘Physiques International’

In between all this she has written for Personal Development magazines and organizations –including Tony Robbins UK division. Has collaborated on book projects with Leslie Kenton –the original Raw Food and female empowerment guru – and written for computer magazines…..and now she is with Natural Bodybuilding and Fitness magazine,, RX, Species Nutrition and of course!

She is a certified personal trainer, hypnotherapist and has been working out since the age of 15.

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