1) Health can affect hair growth. Lack of vitamins/minerals, certain medications, illness or injury to the skin or scalp can all have an impact.
2) Normal daily hair loss is an average of 30-50 hair strands, which are replaced with new hair.
3) Weather affects hair loss, with more hair being shed during the cold months while warm temperatures will activate the growing (anagen) stage of hair.
4) Hair cutting or shaving has no effect on the growth of the hair. Hair seems to grow back coarser because during shaving or cutting you are cutting off the point, the softer end of the hair, to the tougher mid shaft.
5) A single hair strand has a lifespan of about 5 years.
6) At any given time, 90% of the hairs in your scalp are growing, while the other 10% are resting.
7) As soon as a hair is plucked from its follicle a new one begins to grow.
8) Hair grows in three stages: Anagen (growing stage), Catagen (resting stage), and Telogen (shedding stage)