Conditioners - Types
Hair conditioners come under the purview of hair cosmetics and are used to alter the texture and appearance of human hair. Its working and ingredients are far more complex than most hair products, such as shampoos for hair loss prevention and shampoos which spur hair growth. These are used to treat the hair after shampooing occurs.Conditioners help hair regain and refine their look and feel after shampooing. Also they help moisturize the hair, add shine and make them more manageable. Their working is quite like fabric softeners which are used after the clothes are washed with detergent.
Types
Conditioners that help in replenishing oil to the hair
When hairs are washed with shampoos whether they are for for hair loss prevention or to spur hair growth , they lose oil which is removed by the detergent content in shampoos. Conditioners contain humectants, the compounds that hold moisture into the hair. These types of conditioners work best with dry, curly, often frizzy and coarse hair.
Major ingredients of this type of conditioners are cetyl or stearyl alcohol, panthenol and methicones, silicone or dimethicone, or essential oils and botanicals such as avocado, jojoba oil, or shea butter. One essential ingredient of oil-based conditioners are EFA, a lubricant similar to sebum.
Protein conditioners
Protein conditioners give hair shafts and hair ends a coating protein which make hair appear thicker. They can also help fill gaps if the outer cuticle is damaged, making the hairs smoother and shinier. These types of conditioners work best with fine and limp hair or damaged hairs.
Acidifier conditioners
This type of conditioner lessens static in the hair and improves their manageability particularly when they become tangled after shampooing. They have a low pH of 2.5 to 3.5. These conditioners basically close the cuticle layer of the hair, which in turn allows each individual strand of hair to remain separate from others. These conditioners work best on fine hair.
How to apply
Now it is time for some hair care tips. First of all apply conditioner as per the instructions on the bottle. Take the correct amount (usually a "quarter's" worth) in hands and rub the palms together. Never apply a glob of conditioner to the hair directly.Make sure to apply conditioners only on the hair shaft and ends and spare the scalp. If applied to the scalp it will buildup and impart a limp look. Leave the conditioner on the hairs for at least a minute for best results. Then rinse your hairs thoroughly.
Rinsing the conditioner off completely as directed by the packaging instructions is very important as residues of conditioner on the hair can attract dirt and dust and give the hairs greasy feel. It is also very important to be careful while combing the hairs as they are most vulnerable when wet. This is when the most damage can occur.
Remember, hair cosmetics like conditioners can never change the structure of the hair as they cannot penetrate the hair and improve the internal fiber structure. Though some kinds of conditioners (as discussed above) may give hairs a coating of proteins or polymers to simulate thickness, they can’t alter the hair structure.
Before going for a particular conditioner consider the type of hair you have - dry, oily, or normal; and also the density of hair on the head. This will help you choose the right conditioner giving your hair the perfect look.

Biology
Hair Cosmetics