Shampooing and Scalp Care
Core concepts
Know the purpose of shampooing: cleansing scalp and hair, removing product build-up, preparing hair for service, and supporting scalp health. Understand how surfactants work: a hydrophilic head and lipophilic tail lift oils and soil into water so they rinse away. Know the difference between anionic (strong cleansing, typical shampoos), cationic (conditioning, often in conditioners), amphoteric and non-ionic surfactants, and why mild or sulphate-free options suit some scalps and coloured hair.
Know pH: hair and scalp prefer mildly acidic to neutral products; high-pH products raise the cuticle and can increase colour loss and roughness. Understand conditioner function (smoothing cuticle, reducing static, improving combability) and that conditioner is applied mainly to mid-lengths and ends, not the scalp.
Master technique: correct water temperature (comfortably warm, not hot), thorough wetting, dilution and lather, gentle massage with fingertips not nails, careful rinsing, and towel drying by blotting rather than rubbing. Know scalp types and matching products: dry/flaky scalp, oily scalp, sensitive scalp, and medicated shampoo use per instructions. Know when shampooing is contraindicated or requires care (open wounds, some scalp conditions).
Traps
Questions often suggest hot water or vigorous nail scratching as good practice; both are wrong. Another trap is applying conditioner to the scalp for oily scalps.
Rule of thumb
Clean the scalp, condition the hair: shampoo works at the scalp, conditioner works along the lengths.