First, identify the patches you want to fill in. Second, determine what color(s) will match your beard hair. Third, find a product that can help you achieve the look you desire such as Just for Men mustache and beard gel which comes in a variety of colors.
Proper diet, exercise, and sleep will increase beard growth. Long beard hair can be directed over thinner spots with a beard brush. A beard trim accentuates the strong parts of your beard.
Is There A Way To Fill In A Patchy Beard?
You can fix a patchy beard by using products like beard oil and beard balm, letting it grow out, trimming around the edges to keep it looking sharp and eating a rich diet to encourage beard growth. 
Can You Actually Fix A Patchy Beard?
Proper diet, exercise, and sleep will increase beard growth. If you don’t get enough through your diet, take a biotin supplement. Long beard hair can be directed over thinner spots with the use of a beard brush. A beard trim accentuates the strong parts of your beard. 
Is It Possible To Fill In A Patchy Beard?
If you just let the hairs grow longer, a patchy beard can be filled in. This might mean growing a disproportionate beard in some spots, as you maintain the length of your mustache but let the cheeks grow in more. 
Frank Harmenstein is the lead editor of the grooming website Cut Throat Straight Razor, and has over 15 years of experience in the industry. He’s personally tested and reviewed over 200 different straight razors, and has written countless articles on the subject.