Vomeronasal organ in the nose picks up scents of pheromones through bodily fluids (sweat, urine etc). Same thing for testosterone.
It is known if a women smells test the women experiences a slight change in blood pressure, heart rate, breathing, and body temperature... basically it induces a small flight or fight response.
Now what's interesting is that the flight or fight response can be interpreted as scary or exciting depending on the situation at hand. A bear in the woods will give me flight or fight and make me scared, a beautiful woman talking to me will give me flight or fight response in the form of "butterflies in my stomach."
So yes, I'll believe it. Although, it is very, very subtle.
It will never make women attracted to you... but it will intensify an attraction if there is one. That's all.