I don't understand when you say it can screw up your receptors. Which receptors are you talking about?
Cytomel is a brand name. liothyronine is the generic name, also known as T3.
Commonly prescribed for hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. Without this hormone, the body cannot function properly, resulting in poor growth, slow speech, lack of energy, weight gain, hair loss, dry thick skin, and increased sensitivity to cold. When taken correctly, liothyronine reverses these symptoms.
When taken in normal humans, it causes the body's metabolism to speed up, thus buring fat and muscle. Thus the belief that it is anti-anabolic.
As far as tolerance, as with any other exogeneous source of hormones, the body will adapt to maintain a natural level of T3 in the bloodstream. The body's own thyroid will shut down as a result in the increase in T3 circulating in the bloodstream. Typically, the maximum time that you should take this drug is 4 weeks. After that, the body's own thyroid will stop producing.
Unlike the testes in the male, the thyroid gland may not start producing the hormone upon cessation of the drug. In the event that it does, there is a lag time between your body's own production and the time that you stop. So your metabolism is basically at a standstill. That is why you see so many fitness chicks blow up after a contest.
It is best to taper off if you decided to use this. I do not see any benefit in tapering into it. Also, I would not exceed 50mcg (micrograms, NOT milligrams) per day.
There is another form of the thyroid hormone, T4, which is safer but less metabolically active. The body has to convert T4 into t3 before it has any affect on the body.
Remember, each individual is different, and what works for one may not work or react totally different in another individual.
Hope this helps