Yes and no. that would only happen if you went to krypton. you wouldnt have to go to krypton in order to be under a red sun. it was also said that we wouldnt be able to use the solar energy, but that isnt completely true either. we use solar energy just not the way superman does. if you think about it, under the red sun superman would be equal to a human which means that he wouldnt be able to use the suns energy either, yet when he is under the yellow sun he can. by that logic the same thing would happen to humans under a red sun.