Bodybuilding thyroids hormones a pact with devil

Do you remember the first editions of the David Letterman Show, which had a section of what domestic animal were able to do? If you never saw it or you don’t remember, I’ll make a summery: one blockhead took to the show his well groomed poodle and made it jump through a flaming ring in public to win a prize (generally, a cookie) and the meaningless praises from the audience. It was an absurd show, but fun in a perverted and stupid way. I  never saw a can burning, but that possibility was always around.

When I think about bodybuilding and the thyroid hormones, one of those images from the Letterman show come to mi mind. We have a bodybuilder (the groomed poodle), which uses a dangerous substance (the thyroid hormones -the ring of fire-) to win a trophy and maybe some money (the cookie).

I think it is a good analogy. Nowadays, I receive between 50 and 100 messages from the readers. At first, most of them asked for information about steroids, but lately more and more are related to the following question: How should I use the thyroid hormones to be cut out? Around a 75% of these consults come from women who believe that swallowing pills -and not the hard work and determination- is the best way of loosing fat.

I don’t feel much interest for thyroid hormones because I consider they are about the most dangerous pharmaceutical preparation among the chemical arsenal of the bodybuilders -and, doubtless, more dangerous than steroids-. My intention is to illustrate you about the nature of these hormones and maybe then you will understand why I’m not really interested on them


Thyroid hormones have marked effect on the metabolism, the cardiac function, the growth and development. The metabolic rhythm of most of the cells is directly affected and modulated by these hormones. Also, they increase both the strength as the speed of the cardiac contractions. During childhood and adolescence, they stimulate maturity. The absence of these hormones leads in an irreversible way to dwarfism and deep mental retardation.

Thyroids, a gland with a sandglass shape located in the throat, secrete bioactive hormones: triiodothyronine (T3) and tetraiodothyronine (T4, but also known as thyroxine). The structure of these two hormones is very similar; the only difference is that T4 has four groups of iodine and the T3 only three.

The biological effects of T4 and T3 are quite alike, however, when compared at mole or microgram amounts, T3 is between three and four times more powerful than T4. And most of T4 is converted in the organism to T3 because of the action of an enzyme called 5-deidoasa.

T3 and T4, which can be bought in pills, are medicines produced by men which need medical prescription. Synthetic versions are identical to the ones produced by the organism. Synthetic T3 is known with the generic name of Liothyronine and T4 as levothyroxine. Medicines containing both T3 and T4 are usually called generic liotrix.

There is also an injectable version (and incredibly dangerous) of Liothyronine, but bodybuilders will never have access to it.


Thyroid hormones carry out three important actions: the stimulation of the use of energy, of the heart and of the growth and development. The use of energy raises the basal metabolic rhythm, which leads to a higher oxygen consumption, a higher heat production and, therefore, a greater caloric expenditure.

The stimulation of the heart increases both the strength as the speed of the heart contractions, which causes an increase in the cardiac function. In the same way, thyroid hormones play a major role in the development and growth. During childhood, they are essential for a normal brain development and have a significant effect on the skeletal muscle growth exclusively on children.

The synthesis of the thyroid hormones is performed in four steps. I have surrounded with a circle the numbers on the diagram which correspond with the stages I am going to describe.

Step 1: The formation of the thyroid hormone starts with the active transport of iodide to the thyroid. In normal circumstances, during that process iodide concentrations between 20 and 50 times higher to the ones we can find in blood plasma are registered in that gland.

Step 2:Following, the iodide is oxidized and becomes iodine (the bioactive form of iodide). The enzyme peroxidase is responsible for that oxidation.

Step 3A-3B: Activated iodine joins the tyrosine residues that are attached to a thyroglobulin (a large glycoprotein). As I show on the diagram, a molecule of tyrosine can receive one or two iodine atoms, with which monoiodotirosina (MIT) or diiodotirosina (DIT) is produced.

Step 4A-4B: The last step of the thyroid hormones production consist of the union of the iodized tyrosines. Joining one MIT with one DIT you obtain T3 and joining one DIT with another DIT you get T4.

The hormonal secretion of the thyroid is produced by a proteolytic process. The amount of T4 released is higher that the T3. Although, most of T4 is converted into T3 because of the action of that enzyme located in the peripheral tissue called 5-deiodasa. In fact, 75% of T3 in the blood torrent comes from the conversion of T4 into T3.

Over the 99% of T3 and T4 found in the blood torrent is attached to plasmatic proteins, and, therefore, there is only a small quantity of thyroid hormone to produce biological effects (if it is attached to a protein, it gets temporarily useless). Thyroid hormones are eliminated through the hepatic metabolism and, since most of it is attached to plasmatic proteins, have an average long life: about two days the T3 and about seven the T4.

Thyroid hormones are regulated by the hypothalamic-pituitary-testicular axis. The hypothalamus secretes the hormone that releases the thyrotropin (TRH), which acts on the anterior pituitary gland, causing the secretion of the thyroid stimulating hormone (TSH).

The TSH then acts on the thyroid gland and stimulates all aspects related with the secretion of thyroid hormones. If I take synthetic thyroid substances, my T3 and T4 level in plasma will increase. The hypothalamus will detect that increment and will reduce the TRH production and, hence, the endogenous level of thyroid hormones will decrease.


If you are smart, you will understand the consequences the consumption of thyroid hormones can cause to a bodybuilder. In the case you are not so intelligent I will explain it to you.  Bodybuilders use thyroid hormones to increase their metabolic rhythm and power, so they burn more calories (hoping it is adipose tissue, although it is not always like that). This method is potentially useful on the occasions in which the bodybuilders must get rid of a great amount of fat in a short period of time in order to attend to that important competition.

I don’t like thyroid hormones for a couple of reasons. There is no doubt that in the short term those hormones will make you loose fat at a supersonic speed. However, using them is like making a pact with the devil. You will pay later, and with interests. In contradistinction to the hormonal axis that controls the androgen production, the axis which controls the thyroid hormones is no so adipose.

Therefore, if one persons uses and excessive amount of thyroid substances during a long period of time, his body will decrease or stop definitely its production. He will have to follow medical treatment for ever.

The bodybuilders who use thyroid hormones usually have an amazing appearance the day of the competition, but in a month they gain between 10 and 15 kilos of fat. Bare this in mind: the excess of thyroid hormones increases the basal metabolic rhythm, but also the opposite happens; those hormones deficit will decrease the metabolic rhythm.

When those bodybuilders quit those thyroid formulations, they will suffer hypothyroidism temporarily (luckily). Their thyroid gland will not secrete enough quantity of hormones to keep up a high metabolic rhythm. They have two choices: eat normally and get like an elephant or starve and don’t get fat.

Do you remember I have mentioned that thyroid hormones cause changes in the cardiac function? Well, an excess of these types of hormones may cause an illness called thyroid storm, which can be fatal if it is not immediately treated. Among the secondary effects derived from the consumption of these substances stand tachycardia, anginal pain, tremors, nervousness, insomnia, hyperthermia, heat intolerance and profuse sweating.

If one person needs to be fantastic one or two weeks a year and doesn’t mind about the aspect he has the rest of the time, the thyroid hormones may be an acceptable option. If I wanted to look fine the whole year, I wouldn’t touch those drugs. There are all sorts of thyroid medications. The most used in the United States are Cytomel (liothyronine presented in tablets of 5 and 25 micrograms), Synthroid (compressed from 50 to 500 micrograms of levothyroxine) and Thyolo (liotrix presented in tablets of 60 micrograms in a ratio of T4 and T3 in 4:1).

There is a drug in Europe called Triacana which is almost a thyroid substance, a derivative from liothyronine and that, in principle, is not so damaging to the hormonal axis. I have never seen Triacana, so I suppose its availability is quite limited. If I were determined to take a thyroid drug to loose weight, it is likely I choose Cytomel (liothyronine tablets), since is the one with shortest action.

Surely, I would not take more than 15 and 25 micrograms and not for a long period -21 days at the most. It is possible that many bodybuilders may mock me for my precaution. I’ve heard that some unwise take the trifle of 400 micrograms of Cytomel during several weeks. All of them, with no exceptions, have suffered serious secondary effects. Other bodybuilders may say you can’t loose fat unless you take over 50 daily micrograms, but many of them have been taking these substances uninterruptedly for many years.

Look what will happen to them when they quit those drugs, if they do. I know a woman who was Queen of fitness and decided to quit using these substances. In less than three months she went from a slim 55 kilos to some flabby 82. She was horrible. I guarantee you will never see again a star on stage who was famous nationwide. Her hormonal axis suffered such alteration that she couldn’t even loose the fat she had gained using thyroid formulations again.

Here we have other facts that can be forgotten. Thyroid drugs raise the basal metabolic rhythm and, therefore, the body heat. Any person using these substances will have a sweaty appearance and will be hot. For every Fahrenheit degree that raises the normal body temperature, you will burn 7% more calories than the usual in order to produce this excess of caloric energy.

If you are on a 3200 daily calories diet, you will only burn 210 extra calories per day (or less than 225 grams of body fat per week). If you believe you can raise to that point your body temperature by thyroid drugs, you are wrong. You need a significant quantity to experiment a one or two degrees rise.

Increase the quantity of these substances and you will feel some secondary effects you won’t like. And that increasing of temperature will make you feel awful, as if you have flu. Probably, the best for you is to stay away from these substances and eliminate the excess of body fat by means of proper diet and training.

The risk of using thyroid hormones (with other substances to loose weight, as dexfenfluramine, phentermine, phenylpropanolamine, dinitrophenoi and clenbuterol) does not worth the results. Doing a pact with the thyroid devil may cost your bodybuilding soul.

Share this Story
Load More Related Articles
Load More By fitnessbodybuilding
Load More In Nutrition

Check Also

Bodybuilding workout chest 15 minute

FacebookTwitterPinterestLinkedIn WORKOUT CHEST 15 MINUTE Do you always ...


Herald is the next generation WordPress magazine theme, featuring a fully flexible header with 3 customizable areas and an easy-to-use module builder for unlimited layout combinations

Find out more

error: Content is protected !!