system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is all the hair on my body black, but my beard has a lot of ginger in it?
gpt
Hair color comes from the pigment melanin, which also plays a role in skin and eye color. Melanin comes in different types, which in hair can produce brown or black color (eumelanin) or varieties of "red" colors (pheomelanin).

The types and amounts of melanin produced have a basis in genetics, which is why hair color can be inherited. But you do not have a single hair color, because not every hair follicle on your body produces exactly the same mix of melanin. So it's possible, and quite common, for hair on different parts of your body to be slightly different in color, and even for different hairs on the same part of your body to not be exactly the same.

Plus, it will change over the course of your life; for exmple, many people start out with quite light hair, only to have it get darker as they grow older. And, of course, as you reach into old age your hair starts going grey (the cells which produce the melanin are no longer replenished, meaning no more pigment).

If you look closely at an area that has a lot of hair, close together -- like the top of your head -- you'll probably be able to see the variations pretty easily. Although from a distance it may all look "black", up closer you'd see some hairs that are darker, some that are lighter, some that are a bit more reddish, etc.

Your beard is no different from any other part of your body, in that sense, and variation is to be expected. There may also be some genetic factors which make it more likely for beard hair to have more pheomelanin, but no-one is quite sure yet.