Every hair is grown by a hair follicle, we have about 100,000 of them set deep into our scalp growing hair at the rate of about 0.4mm per day (about 1.2cm per month). The shape of the follicle partly determines whether we have straight or curly hair.
Hair itself is made mostly of tough, structural proteins called keratin which also form the nails and, in other animals, things like horns, beaks, claws, and sometimes exoskeletons. Silk is also related. Only mammals have hair. Because hair is made of protein you'll sometimes get advised to check your protein intake if you're suffering hair loss. We're not sure that's a big concern.
Each hair follicle goes through a hair growth lifecycle which is more interesting than it sounds so bear with me. There's anagen (growth), catagen (regression), and telogen (resting) and then it's back around to anagen. It's at the end of telogen (resting) that the hair is normally shed... up to 100 hairs a day is normal.
So that answers the question of why hair on some parts of your body is longer than others, and how come you can't grow your hair longer and longer forever. The length of your hair is determined by how long that whole lifecycle is. A typical scalp hair follicle spends between 2 to 7 years in anagen (growth), making the normal maximum hair length about a metre. For eyebrows the growth phase ends after at most 7 months.
The sudden loss of hair about three months after a big shock, telogen effluvium, happens because all the hair follicles go into telogen (resting) together at the time of the shock, and after that ends, all the hair falls out at once.
By far the most common cause of thinning hair and eventual baldness is male pattern baldness and female pattern baldness and they are both caused by the same thing... a genetic sensitivity to a chemical derivative of testosterone. The result is that each time the hair follicle comes back around to anagen (growth) the hair is a little thinner and the follicle weaker until one time, no hair is produced at all.
So long as this is caught in time, hair growth can be preserved and baldness prevented. No, really, it's official... the MHRA has licensed and the FDA has approved two drugs for this purpose. Minoxidil is available to men and women and it stimulates bloodflow, and - by means unknown - gets hair growing. Finasteride 1mg is only available for men, and that blocks the effect of testosterone on hair follicles. If you're a man, you have the option of using both at the same time.
Remember that when using these treatments it’s important that your hair growth progress is monitored by a specialist in order to ensure optimum response and safety whilst using these treatments. And there are other hair loss products that can be used to supplement the effects of these proven treatments and are recommended based on each individual's requirements.
The trick to retaining hair growth is catching thinning hair early. There's not a lot that can be done to revive hair follicles that have ceased to function. But those still working can often be stimulated and revived.
The Belgravia Centre is a world-renowned group of a hair loss clinic in Central London, UK. If you are worried about hair loss you can arrange a free consultation with a hair loss expert or complete our Online Consultation from anywhere in the world for home-use treatment.
View our Hair Loss Success Stories, which includes the world's largest gallery of hair growth photos and demonstrates the level of success that so many of Belgravia's patients achieve.