In general, hair grows about a half-inch per month, or 6 inches per year. But factors such as ethnicity and gender also affect the speed of hair growth.
According to Hairstylestalk.com, Asian hair tends to grow faster than Caucasian or African hair because it has the longest growth cycle of these three hair types. On average, Asian hair's growth cycle can last up to nine years, whereas the cycle for Caucasian and African hair ranges from three to seven years.
Caucasian hair grows 1.2 centimeters, or 0.4 inches, per month, according to Hairstylestalk.com. African hair grows 0.9 centimeters, or 0.35 inches, per month. Asian hair grows 1.3 centimeters, or 0.5 inches, a month. In addition, Asians shed less hair than Caucasians and Africans and don't experience as much balding. Caucasians have the highest risk of going bald.
Another Theory on Growth Rate
Hair growth can vary from 0.23 millimeters to 0.6 millimeters per day, according to Centre-clauderer.com. That equates to a range of 0.7 centimeters to 2 centimeters per month, indicating that some people have hair that grows much faster than others'.
Centre-clauderer.com explains that the root, through which hair grows, is linked to the rest of the body through the bloodstream. These roots need a constant input of proteins, minerals, oxygen, vitamins and salt that is provided through the blood so that hair can grow as it is supposed to. If your diet is substandard and you are deficient in vitamins and minerals, this will slow your hair growth.
The maximum length of your hair is determined by the pace at which your hair grows and the length of the growth cycle. Women's growth cycle is from four to seven years, whereas men's growth cycle is shorter, varying from two to four years.
Caucasian hair can be straight or curly. The hair stem is mainly flat and round. In the fastest cases of hair growth, the growth rarely exceeds 1.5 centimeters a month. African hair stems are flat and oval with a propeller-shaped torsion. The hair, which is tendrilled, has a slower growth rate than Caucasian hair. Asian hair has large, rounded stems that make the hair grow quickly.
According to Belgraviacentre.com, Asian hair has a much thicker cuticle than Caucasian hair and twice the diameter. Asian hair has nearly 10 layers of cuticles, while most other hair types have five layers. The individual shafts in Asian hair are thicker than non-Asian hair, which makes it look as though they have a lot more hair. However, Asians have less hair per square centimeter than Caucasians do.