Hot baths can increase growth hormone but require temperatures high enough to pose a burn risk, leading to lesser increases compared to saunas.

“Many of you asked about hot baths, hot bags will increase growth hormone, however the temperatures that you need in order to increase growth hormone are high enough that you run the risk of burn. And so I really can't make any recommendations about hot bath, but if you can tolerate a nice hot bath you are going to get some growth hormone release. However, the hot bath will lead to lesser increases in growth hormone.”