For most men, beard growth begins during puberty, between the ages of 14 and 18.
The hormone, testosterone, is responsible for beard growth; when testosterone levels in the body increase, the beard also begins to grow. Genetics and hormones determine, to a large degree, what kind of beard you have. Testosterone levels can vary and low testosterone can affect how quickly your beard grows and how thick it gets.
Sometimes even if your level of testosterone is high, other factors may mean you find it harder to grow a big, bushy beard. While some men already have a full beard at a young age, genetic, ethnicity, and heredity factors may mean they find it harder to grow a thick beard. But a healthy lifestyle and a good skincare regime will go a long way to help your beard appear thick and bountiful.