As you leave your teenage years behind and enter your 20s you realize that hair loss is an affliction that affects everybody, although in varying degrees of severity.

To distinguish normal hairfall from abnormal hair loss, one must understand the hair cycle. Each strand of the scalp goes through a growing phase termed 'anagen', lasting about 1000 days, a transitional phase called 'catagen', lasting 10 days (the hair stops growing during catagen) and the final resting phase called 'telogen', which lasts 100 days -- the hair then falls out of the follicle to be replaced by a new strand of hair, which will go through the same three phases.

There are roughly 1,00,000 hairs on the average scalp and thus it is said that upto 100 hair strands dying and falling out each day is normal. Most people, however, feel that they should not be losing even a single strand, which is obviously impossible. Hair, as per its life cycle, will grow and periodically fall out -- normal hair loss should not be stressed over, as the 100 strands that fall out are replaced by new ones produced by the scalp.

Certain conditions however, are known to increase this loss dramatically and require treatment/ prevention:

• Stress is the biggest culprit, implicated in both generalised (all over scalp) and patchy (in sections, like Alopecia Areata) hair loss.
  
• Poor nutrition comes a close second, with crash dieting often to blame. Girls starving themselves to look like Kareena Kapoor [Images] often pay for it with severe hair loss after six to eight weeks.

Stress management and eating a healthy, balanced diet rich in proteins, vitamins (especially biotin) and minerals (particularly zinc) are, therefore, extremely necessary to arrest hair loss. Consume plenty of dal, soybean, paneer, channa, egg whites, white meat like chicken or fish, nuts and leafy vegetables. If your work schedule is so crazy that you never know when you'll eat your next meal, ask your doctor to prescribe protein and multivitamin supplements.

• Hair treatments -- perming, straightening and colouring -- are also damaging to your mane and lead to hairfall. Be prepared for at least a 10 percent reduction in hair volume two months after any such treatment. To minimise damage, do not repeat these treatments too often -- once or then twice in a year at the most. Always go to a professional and ask for a hair protecting serum before treatment. Also use appropriate aftercare products.
  
• Another big no-no is over-enthusiastic massaging during oil application, in the mistaken belief that this will increase the scalp's absorption and stimulate follicles. In reality, a vigorous massage will only serve to uproot hair in the telogen phase and lead to hair trauma.
  
• Hair is at its weakest when wet, so never roughly comb it after a wash. Disentangle the strands gently with a wide-toothed comb or wait till they are semi-dry.
  
• Holding a hair dryer too close to the scalp is another reason for hairfall -- the heat can cause lasting damage. Use a diffuser attachment on the dryer, holding it at least eight to 10 inches away and never wait till your hair is bone-dry -- always leave a little moisture in. Cold air drying is, in fact, the best method. Also avoid hot rollers and tongs if you value your locks.
  
• Steer clear of tight hairstyles that pull your hair taut. Indian mothers enthusiastically twist their daughters' hair into tight plaits, thinking this will increase hair length -- it actually only serves to encourage a receding hairline and balding in the frontal areas of the scalp. So keep your hair looking neat, but don't pull and manipulate it too hard.
  
• Losing a lot of hair post-pregnancy is common, because the elevated hormone levels that persist during pregnancy prevent normal hairfall during that period. Once you have delivered your baby, it often happens that these hormonal changes are reversed and you start losing a lot of hair all of a sudden -- there's not much to do except wait it out. Don't panic, because your hair growth and hairfall patterns will eventually return to normal. If the hair loss shows no sign of letting up, however, you may want to consult a doctor.
  
• Certain medications cause hair loss. If you're concerned, ask your doctor whenever you're given a prescription whether the medication has such side-effects and if so, request a substitute if possible. Long periods of illness, chronic diseases, surgery etc. are also reasons why hair sometimes starts falling more than it should, but this is often temporary, nothing that a good diet and adequate rest won't solve.

If you have bald patches, a family history of hair loss, a receding hairline or abnormal loss (a lot more than 100 hairs per day) despite a healthy lifestyle and diet, its time to consult your dermatologist.

Above all, be realistic -- you're not Rapunzel that your hair needs to be ankle-length, nor should you aspire to have a mane like the models you see in haircare advertisements. As you grow older, your hair will not remain as thick as it was when you were a child -- accept these changes gracefully and keep your crowning glory healthy.

Dr Parul S Kolhe is an MBBS and holds a DDV and DNB in dermatology.

Photograph: AFP/Getty Images