When your hair follicles are dead, they do not regrow hair. You can inspect your scalp and look for signs of hair growth. Even if you only see thin hair patches or fuzzy texture, your hair follicles are still alive and will continue to renew themselves.
Surgical treatment such as laser therapy or a hair transplant can help revive the hair follicles. Further, if the situation is not too worse, a hair specialist can also prescribe you supplements that will fulfil the nutritional requirements of your hair follicles.
When your hair follicles have died or become inactive the skin on the scalp takes on a smooth, shiny appearance. This indicates that hair loss has progressed to the stage of true baldness.
After that, a follicle enters catagen – which takes 10-14 days where hair detaches itself from the blood supply at the bottom of the hair bulb. Following this, the follicle enters resting stage, telogen, which takes 3 months.
If hair is pulled out of the hair follicle, it can regrow. It's possible that a damaged follicle will stop producing hair. Certain conditions, such as alopecia, can cause follicles to stop producing hair altogether.
Vitamin C, or collagen, keeps blood vessels in the scalp healthy by supporting hair follicles. Vitamin C also helps you absorb iron from plant proteins. Biotin, an essential B vitamin, strengthens weak hair and improves its texture. Biotin is found in salmon, carrots, egg yolks and sardines.
Environmental Factors – Exposure to dirt, soot, harmful chemicals due to pollution may cause oxidative damage to hair strands and follicles and weaken the hair roots. Hair changes may range from diffuse hair fall, scalp irritation, burning sensation and dandruff to dry, frizzy and brittle hair.
Minoxidil. One very good medication to reactivate dormant hair follicles is minoxidil. Applied regularly to the scalp, minoxidil can re-grow hair that has completely stopped growing.
When hair follicles die, however, hair growth stops completely. To know if your hair follicles are still active, just take a look at the scalp on your head. If you see any hairs on your scalp—no matter how sparse, thin, short or fuzzy—your hair follicles are still alive and kicking and sprouting new hairs.
Here's the truth: You can't change the size of your hair follicles. If you were born with fine hair, it's genetics, and no product will completely alter that. Of course, there are ways to maintain your hair health, add volume, and keep it from getting any thinner.