###Human: Can Levothyroxine intake be harmful to liver and kidney? ###Assistant: Hello. I just read your query and I would like to answer your questions one by one. No, being without thyroid gland will not reduce lifespan. No, Levothyroxine is not harmful to liver and kidney. Synthetic Levothyroxine mechanism is not different from the original. T4 converts to T3 by an enzyme present in the body. There ae no side effects. And of course, you can marry someone and conceive if you are on correct treatment.