Hair is aesthetically a very important part of the human body. All of us desire to have smooth, soft and lustrous hair. This is done with use of shampoos and conditioners.

It is important to understand one's hair type to make the right choice of shampoos and conditioners.

• Normal
• Dry: This type may be a result of
  • Lack of sebum.
  • Environmental factors like sunlight, wind, sea water, chlorinated water (as in swimming pool).
  • Chemical treatment like hair coloring
  • Mechanical injury such as straightening and perming
• Oily or greasy hair: This happens because of excessive sebum secretion from sebaceous glands in the scalp

Shampoos

Shampoo is a suitable detergent for washing hair, removing sebum, sweat, dirt and dead cells present on the hair shaft and scalp.

Types of Shampoos

• BASIC Shampoos
  
  • Normal hair shampoos: They achieve good cleansing with minimum conditioning.
  • Oily hair shampoos: They give excellent cleansing  and very minimal conditioning.
  • Dry hair shampoos: They cause mild cleansing and good conditioning. They reduce static electricity and make the hair more manageable.
  • Damaged hair shampoos: Meant for hair which have been chemically treated with hair color, bleaching agents or hair straightening agents. They have mild detergents and more conditioner in order to temporarily repair the hair surface defects. 
• Baby Shampoos
  These are formulated with 'amphoteric surfactants' which cause little or no irritation. They are mild and can also be used by adults who wish to wash their hair everyday.
• Medicated Shampoos
  • Anti-dandruff shampoos: They, in addition to the regular ingredients also contain additives such as anti-fungals, anti-bacterials, Selenium Sulphide, Zinc Pyrithione, Tar derivatives etc.
    They remove sebum, oil, scalp scales and the anti-fungal acts on the fungus 'Pityrosporum ovale' which is usually the cause of dandruff.
  • Anti-Lice shampoos: They contain Gama-benzene hexa-chloride or Permethrin which kill the lice when applied in a proper manner. 
• Conditioning Shampoos
  They are a combination of shampoo and conditioner. These products may be self-defeating since the shampoo removes sebum, the body's natural conditioner and replaces it with an artificial conditioner.

Conditioners

Shampooing, drying, combing, brushing, dyeing, permanent waving, straightening and styling damage the hair and make it harsh, brittle and entangled. Hair conditioners reverse this hair damage and make the hair manageable, glossy and soft. They increase the strength and reduce the brittleness of the shaft. Conditioners also attempt to mend the split ends ('split ends' result from extensive damage to hair shaft).

Conditioners are designed to revert the hair damage caused by several factors as given below.

1. Grooming: Damage after wet combing, blow drying, wet brushing leads to damage of the hair cuticle.
2. Environmental insults: Hair may become discolored. There may be damage to the cuticle, split ends and finally breakage of hair may occur due to weathering. 
3. Chlorine and salt water: This weakens the hair shaft, causes split ends and cracks in the cuticle.
4. Heat styling: Blow drying and hot rollers damage the tensile strength of the hair.  
5. Chemical agents: Permanent hair colors, bleaching increase the frictional force of the hair and consequently the combing force leading to breakage. Perming and straightening reduces the tensile strength of the hair and causes hair loss.

Types of conditioners

• Instant conditioners: They are applied following a shampoo, left on the hair for 5 - 10 minutes and rinsed. They provide minimal conditioning due to short contact time.
• Deep conditioners: Usually are marketed as creams. Their ingredients are similar to instant conditioners but are more concentrated. They have to be left on the scalp for 20 - 30 minutes before rinsing. They provide good conditioning.
• Leave in conditioners: They are applied after drying the hair and are left on till the next shampoo. They are in the form of blow drying lotions and hair thickners.
• Sunscreen conditioners: Excessive exposure to sun can cause dryness, loss of color and roughening of surface texture. PABA and Benzophenones are added to conditioners which provide sun protection to hair.

Mechanish of Action

• They seal split ends.
• They protect the cuticle which covers and protects the hair shaft.
• They restore the acidic pH of the hair which is disturbed by the alkaline pH of the shampoos.
• They cause 'fly-away hair to become smoother and more manageable.

In brief dry, brittle and lusterless hair become shiny, bouncy, glossy and strong.