Barbering Chemistry and Product Knowledge
Core concepts
Understand pH (0–14), acids, bases, and how pH affects hair (the hair and scalp are slightly acidic, around pH 4.5–5.5). Know the difference between solutions, suspensions, and emulsions, and the role of surfactants. Know product categories: shampoos, conditioners, styling products, color, relaxers, and disinfectants. Understand oxidation and reduction in chemical services.
Traps to watch
Questions test that alkaline products swell the cuticle (color, relaxers) and acidic products close it (conditioners, toners). Do not confuse an oxidizing agent (hydrogen peroxide) with a reducing agent (thioglycolate). Know that hard water contains minerals that interfere with shampooing. Never mix chemicals unless the manufacturer directs it.
Worked rule of thumb
If a product's pH is high (alkaline), it lifts the cuticle and can damage; if low (acidic), it smooths and seals. Match product to service and hair condition.
Safety
Read labels, follow dilution and timing, store chemicals safely, and never combine products not intended for mixing.