Cosmetology (Kenya TVET CDACC Beauty & Cosmetology) cheat sheet

Hair shaft layers: cuticle (outer, overlapping scales, protects), cortex (middle, 80-90% of mass, holds melanin and disulfide bonds), medulla (innermost, may be absent in fine hair).

pH scale: 0-14; hair and scalp prefer pH 4.5-5.5. The acid mantle resists alkaline disruption; alkaline products swell the cuticle, acidic products tighten it.

Disulfide, hydrogen, salt (ionic), and peptide bonds govern shape and strength. Wet hair breaks hydrogen and salt bonds, so it stretches more; disulfide bonds are only changed by chemical texture or relaxer services.

Side bonds: disulfide (permanent, thio/perm chemistry), hydrogen (broken by water, reset by drying), salt (broken by pH changes, reset by acidic rinses).

Hair growth cycle: anagen (growth, 2-6 years), catagen (transition, a few weeks), telogen (rest, about 3 months), then exogen shedding.

Porosity: low porosity resists moisture and needs heat or longer processing; high porosity absorbs and loses moisture quickly and processes fast. Elasticity tests strength: wet hair should stretch 50% of length and return.

Density is strands per square inch (thin, medium, thick); texture is strand diameter (fine, medium, coarse). Do not confuse them.

Melanin types: eumelanin (brown-black) and pheomelanin (red-yellow). Gray hair lacks melanin but retains the same protein structure.

Sebaceous glands secrete sebum (lipids); eccrine sweat glands regulate temperature. Scalp sebum production declines with age and is influenced by hormones.

Four basic haircut forms: solid (no elevation, 0 degrees), graduated (stacked, low elevation), layered (high elevation, 90 degrees or more), and uniform (same length throughout, follows head shape).

Elevation controls volume: 0 degrees builds weight at the perimeter, 45 degrees creates graduation, 90 degrees removes weight, and 180 degrees creates maximum length and movement.

Distribution: natural fall follows the head shape; shifted or perpendicular distribution redirects hair for diagonal and directional lines.

Guide types: stationary (fixed, one section) versus traveling (moving, follows previous section). A cross-check verifies the cut with a perpendicular section.

Cutting lines: blunt (weight, strong perimeter), graduated (built-up weight), layered (movement), and razor cutting (soft, textured ends).

Permanent wave chemistry: reducing agent (ammonium thioglycolate, pH about 9-9.6, or glyceryl monothioglycolate, acidic pH about 6.5-7) breaks disulfide bonds; neutralizer (hydrogen peroxide or sodium bromate) rebuilds them.

Relaxer chemistry: hydroxide relaxers (sodium, potassium, lithium, guanidine) are lye-based and not compatible with thio perms; ammonium bisulfite is a low-pH option. Always follow manufacturer timing.

Hair color: temporary (acid dyes, large molecules, coat the cuticle), semipermanent (direct dyes, no lift, deposit only), permanent (oxidative, ammonia opens cuticle, peroxide develops).

Volume of developer controls lift: 10 vol (3%) deposits, 20 vol (6%) lifts 1-2 levels, 30 vol (9%) lifts 2-3 levels, 40 vol (12%) lifts 3-4 levels.

Patch test about 24-48 hours before aniline-derivative color; strand test before chemical services. Record formula, timing, and developer volume in the client record.

Thermal styling: blow dryer heat softens hydrogen bonds; the set is fixed as hair cools. Thermal irons should not exceed about 450 F (232 C) on human hair.

Skin layers: epidermis (stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum), dermis (collagen, elastin, nerves, glands), and subcutaneous (fat).

Skin types: normal, dry (alipidic), oily, combination, and sensitive. Fitzpatrick scale (I-VI) estimates sun response and guides treatment selection.

Cleansing steps: cleanse, tone, exfoliate (physical or chemical), massage, mask, moisturize, and sun protection. Exfoliation increases photosensitivity.

Nail anatomy: nail plate (keratin), nail bed, matrix (growth site), lunula (visible matrix), cuticle (eponychium), hyponychium (seal under free edge), and nail folds.

Nail growth averages about 3.5 mm (1/8 inch) per month for fingernails and about 1 mm per month for toenails; growth slows with age and in cold weather.

Nail disorders: onychosis (disease), onychocryptosis (ingrown), onycholysis (separation), paronychia (bacterial infection of the fold), onychomycosis (fungal). Refer infections to a physician.

Manicure/pedicure safety: single-use files and buffers, disinfected implements, no cutting of live tissue, and no service over inflamed, broken, or infected skin.

Contraindications for skin services: open lesions, active infection, recent chemical peel or laser, sunburn, and known product allergy. Patch test aniline-derivative products.

Licensing is regulated by state boards; scope of practice, sanitation rules, and continuing education hours vary by state. Verify requirements with the state board.

Client consultation: assess hair and scalp, discuss history and expectations, patch test when indicated, and document the service and products used.

Business math: retail price = cost / (1 - markup percentage); gross profit = revenue - cost of goods sold; profit = revenue - expenses.

Rent vs. commission: chair rent pays a fixed fee; commission pays a percentage of service revenue. Booth renters are usually independent contractors, not employees.

Record keeping: retain client cards, consent forms, and chemical service records per state requirements; keep them confidential and secure.

Professional liability insurance covers claims of injury or negligence. General liability does not cover professional services.

Federal law: OSHA requires a hazard communication program and Safety Data Sheets (SDS) for chemical products; the FDA regulates cosmetics labeling.

Employment law basics: minimum wage, overtime, and child labor rules apply; misclassification of employees as independent contractors carries penalties.

Ethics: informed consent, honest pricing, no guarantees of results, and referral to a physician for conditions outside the scope of practice.

Pathogens: bacteria (cocci, bacilli, spirilla), viruses, fungi, and parasites. Only some bacteria form spores (e.g., Bacillus, Clostridium); spores resist standard disinfection.

Levels of decontamination: cleaning (removes soil), disinfection (kills most pathogens on nonporous surfaces), sterilization (destroys all microorganisms including spores).

EPA-registered hospital disinfectant with a tuberculocidal claim is used for blood or body fluid contact. Follow label contact time; do not mix chemicals.

Universal precautions: treat all blood and body fluids as infectious. Wear gloves, use a barrier, and wash hands for at least 20 seconds.

Blood exposure: stop service, apply gloves, clean the wound, apply pressure, clean the area with an EPA-registered disinfectant, and report per policy.

Implements: porous items (files, buffers, wooden sticks) are single-use or discarded; nonporous tools are cleaned then disinfected in an EPA-registered solution.

Electrical safety: use ground-fault circuit interrupter (GFCI) outlets near water, inspect cords, and keep cords away from water and heat.

Ergonomics: adjust chair and station height, keep wrists neutral, take stretch breaks, and alternate tasks to reduce repetitive strain.

Chemical safety: read SDS before use, ventilate the area, store chemicals away from heat and sunlight, and never store chemicals in unlabeled containers.