Nigerian culture is rich and diverse. There are many traditions that have been passed down from generation to generation, and the tradition of wearing a silk cap before bed. We found the question of why do some black people wear silk caps before they go to sleep so I did some research on it.
Some white people also wear silk caps for sleep, because of the benefits! It’s mainly best for people with curly hair or hair that will dry out quickly.
Anybody not wanting to wear a silk cap to bed could use a silk pillowcase instead.
Silk pillowcases are better for the hair because they don’t tug or pull at your curly locks, which can cause frizz and breakage. They also reduce facial wrinkles. And help retain moisture.
Cotton pillowcases can suck all the good moisture from your face and especially hair. Investing in silk sheets and pillowcases is a good technique to help with protecting your hair , particularly if you have cornrows, twists, braids, buns and other protective styles.
Because silk is smooth (e.g. straight and sleek), it prevents moisture from escaping and reduces friction in the hair.
According to the L’Oréal Group on why black hair seems not to grow, is because the hair is unlike any other. It is extremely fragile and requires a little more care. It is also prone to manipulation because it has bends and twists. Below is an image of the findings.
Hair growth measurements  using phototrichogram found that:
• African hair is characterized by both slow hair growth and low hair density
• Chinese hair also has a low density but grows very fast
• Caucasian hair grows at an intermediate rate per day and is very dense