Native English speaker and writer with Master's degree and a strong sense for tone and voice in a message. Not knowing the tone desired from the sample paragraph provided, I took a slightly humerous slant when I rewrote it. I hope you like my approach and would like to work together on future rewrites.
"Hair loss: Few words strike more fear in people's hearts. But, did you know that we all lose hair - as much as 10% of it - on a regular basis? Like most things in nature, hair follicles go through cycles of new growth and rest. When in a growing phase, which typically lasts 2 - 6 years, hair grows a half-inch to one inch per month on average. Then, at the completion of a growth cycle, the follicles enter a period of rest during which many of them release their strands to make way for another cycle of new growth. Don't be alarmed that the resting period lasts about 3 months because, while we lose approximately 10% of our hair in that time, the other 90% is actively growing!"