It’s not the amount of testosterone or DHT that causes baldness; it’s the sensitivity of your hair follicles. That sensitivity is determined by genetics. The AR gene makes the receptor on hair follicles that interact with testosterone and DHT. If your receptors are particularly sensitive, they are more easily triggered by even small amounts of DHT, and hair loss occurs more easily as a result. Other genes may also play a part.
"Age, stress, and other factors can influence whether you experience hair loss. But genes play a significant role, and men who have close male relatives with MPB have a much higher risk of developing MPB themselves." Says Christine Case-Lo.