Male Pattern Baldness How Do I Know If It's Male Pattern Baldness Or Just Stress Or Weight Loss?

How do I know if it's male pattern baldness or just stress or weight loss? - male pattern baldness

Since I was the age of high school, I "m 21 now have times when my hair falls to a value of about 4 liters of space in my head, but always there yet. How do I know if it's stress, weight gain or male pattern baldness?