Men, and sometimes women, notice that their hair is thinning prematurely for several different reasons. Age, menopause, pregnancy, genetics, illness, and other factors all play a role in hair loss.
Hair is made in hair follicles. A hair normally grows from each hair follicle for about three years. It is then shed, and a new hair grows from the follicle. As balding develops, affected hair follicles gradually become smaller than normal. Each new hair that grows is thinner and shed more quickly than before. This eventually leads to a much smaller hair follicle and a thin hair that does not grow out to the skin surface.
saw palmetto has been shown in some small studies to be effective for preventing hair loss in some men.
DHT production causes hair loss,
Saw palmetto also blocks the production of DHT (a metabolite of testosterone)

Vitamin A: Vitamin A is an anti-oxidant, which promotes healthy production of sebum in the scalp.
Vitamin E: This vitamin stimulates circulation, and good blood circulation in the scalp is important in keeping your hair follicles productive.
B vitamins: The B vitamins help your body produce melanin, which gives hair its healthy color. Melanin also stimulates blood circulation.

Topical Treatments
use a few drops of lavender or bay essential oil in an almond, or sesame oil base on your scalp.
Massage promotes good circulation in the scalp, to keep your hair follicles active. Massage your scalp daily by hand for a couple of minutes
Restore moisture through hot oil treatments
Try rubbing your scalp with garlic juice, onion juice, or ginger juice.

Lifestyle Changes
Include more high-protein foods in your diet.
Reduce stress
Good nutrition, especially adequate levels of iron and vitamin B, is helpful. Treatment of underlying medical conditions like thyroid disease, anemia, and hormonal imbalances may useful in prevention.

Male-pattern baldness
Male pattern baldness is the common type of hair loss that develops in most men at some stage. The condition is sometimes called androgenetic alopecia.
Two medicines that may be effective in treating male-pattern baldness are:
finasteride minoxidil!

Finasteride
Type of medicine -5-alpha reductase inhibitorUsed forMale pattern hair lossAlso calledPropecia®Available asTablets
It works by preventing the hormone testosterone being converted to the hormone dihydrotestosterone (DHT). DHT causes the hair follicles to shrink, so blocking its production allows the hair follicles to regain their normal size.
finasteride can increase the number of hairs people have (hair count)
Less than one in 100 men who take finasteride experience a loss of sex drive(libido) or erectile dysfunction

Minoxidil
minoxidil usually needs to be used for several months before any effect is seen
The medication contains either 5% or 2% minoxidil. Some evidence suggests the stronger version (5%) is more effective
Female-pattern baldness
Minoxidil is currently the only medicine available to treat female-pattern baldness.
women respond better to minoxidil than men.