Deep Conditioning: Dry Hair, Wet Hair or Shampoo Hair?

Continuing on with the deep conditioning update, I know I was supposed to discuss about time and temperature next but it occurred to me that an important question that is often asked is about the initial step before conditioning.

1. Oil as a conditioner (pre wash treatment)

Oil for the purpose of conditioning is always applied to dry hair. This is because water repels oil and if your intention is to use oil to penetrate hair then your hair needs to be dry. You can wet your hair first or mix the oil in conditioner if:

-you want to limit how much water penetrates hair
- you do not like how your hair feels when oil is applied to it dry
- you want to use the oil to seal in moisture
- you want to use the oil to help reduce damage post washing

2. Water based Conditioner

For this article I am referring to a regular water based conditioner (deep, intensive, mask or rinse out) that is coated onto hair with the purpose of repairing damage, softening, cuticle smoothing and/or moisturising.

Scientifically, the preferred method of getting the maximum amount of conditioner to adsorb and then potentially penetrate (only ingredients that can) is :

1. Shampoo with a product containing anionic (negative) surfactants
2. Rinse off shampoo - this is important
3. Apply conditioner which contains cationic (positive) surfactants 

Possible Questions:

Q: Why use a shampoo first?

Hair carries a slight negative charge which is enhanced when you use a shampoo with a negative charge. Hair will adsorb the conditioner better because the positive charge in the conditioner is attracted to the negative charge on the surface of hair. For the purpose of getting the best result from a shampoo, surfactants with a charge are best for example
- gentle sulfate shampoo - SLES (sodium lauryl ether sulfate) which is negatively charged
- mild sulfate free shampoo - cocamidopropylbetaine/cocobetaine/cocabetaine which is zwitterionic

Q: Why should you rinse off the shampoo?

Some naturals like to 'buffer' their shampoo by directly adding conditioner to it before rinsing it off. Some also like to simply apply the conditioner before rinsing off the shampoo. In both these cases, the negative charge of the shampoo and the fact that it is present in a large amount interferes with the ability of conditioner to stick to the surface. Two outcomes are possible in this case:

1. Conditioner does not stick to the surface and is washed off along with the shampoo
2. The shampoo and conditioner bind together and create build up on the surface of hair.

Q: Can you condition first and then shampoo?

Yes you can but you will be removing conditioner that stuck to the surface of the hair from the initial conditioning process. You will need to condition your hair again in order to smooth the cuticle. Your process would look like

-Deep Condition
-Rinse
-Shampoo
-Rinse
-Rinse out conditioner
-Rinse
- Leave ins, oils, styling products etc

Q: Can you deep condition on dry hair?

Yes you can but remember the rules about using shampoo afterwards (see the question above). Applying shampoo first and rinsing before applying a conditioner does however give the best result in terms of conditioner adsorption.


References 
J Soc Cosmet Chem, pp 351-359, 1991


J Soc Cosmet Chem, pp 263-278, 1993


Ok, next post is on temperature and time of application of a conditioner.
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