Basically, they can be same thing. Place differs.
Hormones = internal
Pheromones = exogenous / external
For this reason, in some science lit, you see pheromones referred to as “skin steroids”.
Some molecules you won’t really find internally in the body, in any quantity that matters. Androstenone is a prime example. It seems to be a “waste” or “end product” of testosterone metabolism, the “waste” byproduct finding a new life as a pheromone (a marker, a messenger).
Some molecules serve a dual purpose.
Rone is a classic example. Rone is used internally in the body as a hormone. When your body is done with it, you excrete it through your urinary and sebacious channels. (ever notice a huge whiff of androsterone in an unwashed men’s restroom?)
When it’s external to the body in this way, it leads a second life as a pheromone.
The quantities used internally vs. externally are enormously different. Internally, you’re talking milligrams to have an effect. I think the body makes something like 9mg to 10mg of rone a day. If you were to get a prescription for rone, it would involve quantities like this. (actually, usually much larger to compensate for loss that occurs during absorption)
Externally, on the other hand, micro, nano and possibly even pico grams of pheromones are active.
The message (which is basically what a pheromone is, a message) is basically light and compact compared to the package it’s describing.