When T3 and T4 are combined for use in bodybuilding, how are their dose assigned?

In the human body, the thyroid hormones T3 and T4 exist simultaneously, one acting quickly and the other providing a slow and long-lasting effect. Rather than using one of them alone, the ideal idea for many BodyBuilders is to use them together. If use T3 and T4 together, how should we allocate the dose ratio of them?

We can start by understanding the ratio of T3 to T4 in the body’s naturally produced thyroid hormone. The thyroid naturally produces about 20% of the body’s T3, and the other 80% of T3 convert into T4 by tissues other than the thyroid. About 40% of the T4 produced by the thyroid gland is eventually converted into T3.

T3 and T4 dose 

When Bodybuilders choose a combination of T3 and T4 dosages, the usual ratio is 1:4 or 1:2. The thyroid gland of a normal adult usually produces 10-20 MCG of T3 and 94-110 MCG of T4 per day.

Of the finished thyroid hormone combinations on the market today, a common daily dosage is T3 containing 12.5mcg and T4 containing 50mcg. For professional Bodybuilders, double the daily dose of 25mcg T3 and 100mcg T4 is also used. This is actually 1:4 of the combined dose of T3 and T4. If used in a ratio of 1:2, when the dose of T3 is 12.5mcg, the dose of T4 is 25mcg. Professional bodybuilder will increase the dosage, but it is best not to exceed 50mcg: 100mcg limit, because this is a very high dose, will bring more side effects.

The two dose ratios of T3 and T4, should I choose to use 1:4 or 1:2 dose?

This depends on a number of factors, including personal reactions, bodybuilding’s purpose, and history of illness. Obviously, thyroxine T4 is milder and T3 is more potent, so 1:4 is milder than 1:2, making it friendlier and safer for bodybuilder. Therefore, you can choose your own combination ratio according to your actual situation.

However, as with anabolic steroids, the use of thyroid hormones in large quantities can disrupt the normal function of the thyroid gland, so do not blindly increase the dose or increase the cycle length. It is best to test the body’s thyroid hormone levels before, during and after use and adjust the dose accordingly or stop using it.