My boyfriend is always hot what could be the reason?

Some reasons...: Feeling hot doesn't necessarily mean something's wrong with you - that could just be your normal resting temperature. And some people are more sensitive to heat than others. If your boyfriend is otherwise healthy, i wouldn't worry too much about it. If he's having any other symptoms like heart racing, hair loss, diarrhea - he should get a checkup by his doctor. Hope this helps!

Hyperthyrodism?: While it can be normal to feel hot, it can also be a sign of hyperthyroidism, a disease where your body metabolism is raised by the overproduction of thyroxine. You should have this evaluated.. Also does he feel hot or is he constantly running a fever? A fever of unknown origin is always a concern and should also be carefully evaluated by a physician.