If it's a part of your immune system and the body can make use of it, such as in fighting infection, or even in making thyroid, and it is not in excess, it doesn't make you tired. In fact, that it is needed in the production of thyroid makes it contribute to energy production, and saying that it makes one tired is not giving it due credit.hydrogen peroxide makes you tired. it acts like free radical. it's the same component your immune system produces when you are stressed or have infection.