Shampooing, Conditioning, and Scalp Care
Water, pH, and product choice
Scalp and hair sit at roughly pH 4.5-5.5, so acid-balanced shampoos are the default for chemically treated hair because they close the cuticle and support color retention. Shampoo should be chosen for the scalp and conditioner for the hair: an oily scalp with dry ends may need a clarifying shampoo at the scalp and conditioner on the ends only. Ask about medications, recent chemical services, and allergies before the service.
The service
Drape properly, test water temperature on your inner wrist, and use the pads of the fingers, never the nails. Standard manipulations are effleurage (gliding), petrissage (kneading), friction or champing, tapotement (percussion), and vibration. Never massage over abrasions, sunburn, or an undiagnosed scalp lesion.
Scalp conditions
Pityriasis capitis (ordinary dandruff) responds to medicated shampoo. Seborrheic dermatitis, psoriasis, and tinea capitis (ringworm) are outside the cosmetologist's scope; ringworm and pediculosis (lice) are contagious and require referral, and disinfection of implements and linens.
Conditioning
Conditioners work through humectants, proteins, and silicones. High-porosity hair absorbs and loses moisture quickly and benefits from protein; low-porosity hair looks weighed down and needs lighter products. Treatments are applied to the hair, not scrubbed into the scalp, unless the product is labeled for scalp use.
Traps
Questions often blur shampoo and treatment: shampoo cleans the scalp, conditioner treats the hair. Another trap is the claim that a salon can cure a scalp disease.
Rule of thumb
If the scalp is broken, inflamed, or infected, shampoo gently or not at all, and refer.