ANTENNAS OF YOUR BODY
Hair is the most potent, purest form of protein in the world. The very root of the hair has the oil of the protein. This oil is enough to support your brain through any activity. One thing Nature knows is that in every part of your body you have to have hair, because they are the antennas for that area of the body. Each cell in the body goes through certain changes, and who is to provide that change in the antennas? Hair.
Hair is the pranic antenna. It is energy, pure protein. Take a bunch of cut hair and put it around a tree and see what happens to the tree. It shoots up.
VITAMIN PROVIDER
God is not just a mischief-monger to give a human the longest hair on the scalp. Its purpose is to work on the brain. The brain needs vitamin D, energy, phosphorus, and metals. The number of units of vitamin D that these hairs provide immediately to the brain is unbelievable.
RISHI KNOTS (Jura) AND WOODEN COMBS
It is very positive for a woman to wear her hair tied on top of her head on the solar center in a rishi knot. It is obligatory for the woman to wear her hair down at night, loose or in a braid. Braiding the hair at night is one of the most wonderful ways to take care of your most powerful energy antennas. For normal health of her eyes, menstruation cycle and long maintenance of her youth it is obligatory that she use a wooden comb, combing her hair back, forward, back, and so on. This is for circulation of the scalp area.
Men tie a rishi knot almost where the soft point was when he was a child. A woman's hair is supposed to be tied exactly at the solar centers. Why? Well, she doesn't have a beard and we never asked why. Because of the waning and waxing of the moon, she has to protect her solar centers more powerfully than the male.
When a woman's hair is loose, her identity to submit becomes a hundred times greater. In old times it was a custom that when a woman went to her husband in intimacy, she let her hair down. Unfortunately, now, during the day, everybody has their hair loose. Understand this action in the light of the downfall of sexual values. The old Judaic and Islamic scriptures say that a "woman with loose hair and a mad dog have no difference whatsoever as far as integrity is concerned."
Men should also comb their hair with a wooden comb. A wooden comb is one simple thing which does not create any charge or discharge of electromagnetic energy. That's why we use wood. Wood is surely and definitely a bad conductor of heat and electricity. It is a very healthy thing for combing your hair.
WOODEN COMBS
The wooden comb is for whenever you feel low in energy. Just comb your hair back and forth with a wooden comb, right there on the spot. It is just like a shot in the arm. Try it sometime. It works much faster than you can imagine. The wooden comb is a very virtuous thing.
HEAD COVERINGS
It is written that it is very non-righteous to expose your hair to the cruelty of the change of weather. The Eskimos keep their heads covered all the time. In the tropics, even the basic tribes have their heads covered, just like we tie a turban.
SHAVING THE HEAD 
In ancient times, shaving the head was a sign of the slave, so all monks were to be shaven. And they were just spiritual destitutes. They depended just on that message, that is why it was made possible to dishonor them by cutting off their hair. Cutting the hair on your head, on the crown, does nothing but dishonor yourself. Ancient man through all his knowledge knew it, but there were so many monks that it became a fashion. The barbers took over.
A monk is a person who only carries a message and is dead in his personality. If you take a monk by the neck and beat him to death, he should not utter a word, if he is a monk. That person has the right to shave his head. Shaving your head means you have lost your total existence, energy, and your contact with God. You are only carrying the master's word, you have nothing of your own.
For many centuries, even in the West, the knights, the barons, and all those big people, when they lost a war, they never were killed. They used to ask for death, but the winning knight would just cut off the locks of hair of the loser.
BANGS 
A woman should never wear her hair over her forehead. God can grow hair wherever He likes, but no hair grows on the forehead. The forehead bone, the sinus bones or the frontal bone, is porous because it functions to transmit light to the pineal gland in the brain.
An experiment was done in which 40 women covered their forehead area between the eyebrows and the hairline for 40 days. The result was that those women could not look into the eyes of a male.
LEGS AND ARMPITS
Most women in America shave their legs and armpits. Perhaps if they realize that by cutting the hairs under the arms they are affecting their magnetic field and the sympathetic nervous system and that by shaving the leg hairs they are altering the electromagnetic field of the lower spine, they might think twice about shaving. Women do not understand what those tiny, tiny hairs on their legs do for them. They only know they are bad things. You know how the legs move, right? On both sides of the legs there are hairs. Those hairs create an electromagnetic field which balances the movement of the pituitary. You shave it and it is your problem; they say it can make you insane.
From the book Ancient Art of Self Healing which is a collection of excerpts from lectures, notes and classes by SSS Harbhajan Singh Khalsa (Yogi Bhajan) .