I'm 20 yrs old and still not getting beard on my face. Any suggestions?

Barring any underlying medical
conditions that are known or unknown, you may simply not have the
genes to grow facial hair. Did your father or grand-father (on both
sides of the family) have issues with beard growth? Do some family
history research to find out. If you don't find answers there, then
consult your primary care doctor to make sure you are not suffering
from some unknown medical condition that inhibits your beard growth.

If your primary care doctor finds that
you do not have a medical condition causing this, then see a hair
transplant doctor for an exam and diagnosis to see if you are a
suitable candidate for a facial hair transplant.Remember that you are still young. Give it a few years.

Every young lad wishes for a full beard that they see on celebs and stars on themselves while they just hit their twenties. However, it is essential to understand that this is not ideally possible because the pubertal process is initiated only during late adolescence.
Testosterone is the androgen hormone found in the male body. This hormone is responsible for the growth of facial hair and other secondary sexual characteristics in the male body. As the hormone levels rise in the male body, it encourages the vellus hair (peach fuzz) to become coarser and thicker over time.
So when does facial hair reach its full growth?
Facial hair goes through many a modification during the twenties and finally reaches its full growth during the thirties.
There are other factors that come into play such as; pubertal age, genetics, testosterone levels etcetera that determine how fast and how much a patient's beard can grow.
What are some red flags?
If the patient does not hit puberty at all.
If the patient has hormonal co-morbidities like gynecomastia.
If the patient surpasses the rough age of when their male relatives (biological) grew their facial hair.
If the patient does not notice any change for many years.
These are some red flags that may require the assistance of a physician to rule out underlying conditions and treat the patient.
What can be done if one has reached full growth and is dissatisfied?
When patients want a fuller beard or mustache, they can always opt for a beard transplant. This procedure transplants the hair follicles from the scalp to the face to give a much fuller look and feel.

Beard hair growth can mature well into a man's 30's so not having a beard at 20 is very possible. You can look at others in your family also to see if this is a common trait. It is well worth waiting for a few years before deciding whether you wish to do something. At your age your body is natural changing and very easily so could your beard. 

Facial hair, like body hair: arms, legs, chest and back varies considerably from one man to another.  It is genetically programmed how much body hair you will have and has nothing to do with your testosterone levels. In males, body hair can continue to change through your life time.  For example, hair tends to grow more on the chest and back up until about age 40 while the scalp hair typically declines in this period, regardless of the testosterone levels. Your beard started growing when you hit puberty and can continue to thicken until your mid 20s but after that should remain fairly consistent in density.  Some men naturally have full beards and some have patchy beards and other than transplanting hair into the beard, there is nothing you can do to really alter the hair growth of your beard.  I would consult a dermatologist if you are want an expert opinion on any hair question. Masturbation will not have a negative or positive affect on your body hair, facial hair, scalp hair nor your testosterone levels.

Check out your family and see when your brother, father and grandparents grew out their hair.  This is genetic and it will eventually come out. If not, a beard transplant is a good solution but only when you are 5 years older.

If you thin beard or facial hair it mY be genetic you need  to wait a few more years as it may still grow out.  If it still does not grow doing beard transplant is a good option and it is very successful.