MO Cosmetology cheat sheet

pH scale runs 0-14; 7 is neutral, below 7 acidic, above 7 alkaline. Hair and skin are naturally acidic at about pH 4.5-5.5.

The hair shaft has three layers: cuticle (outer protective scales), cortex (bulk, contains melanin and disulfide bonds), and medulla (innermost, absent in fine hair).

Disulfide bonds between cysteine residues in the cortex give hair strength and shape; wet hair stretches up to 50% of its length before breaking, dry hair about 20%.

Normal hair pH range is 4.5-5.5; alkaline solutions swell the cuticle, acidic solutions contract it and add shine.

Human hair growth averages about 0.5 inch (1.25 cm) per month; the anagen (growth) phase lasts 2-6 years, catagen weeks, telogen about 3 months.

Skin has three layers: epidermis (outer, no blood vessels), dermis (nerves, glands, follicles), and subcutaneous (fat).

Melanin types: eumelanin gives brown-black pigment, pheomelanin gives red-yellow; absence of both produces gray/white hair.

Nail plate is made of keratin; the nail grows from the matrix under the proximal nail fold, averaging about 0.1 mm (1/8 inch) per month.

Shampoo surfactants lift oil and soil; the anionic surfactant is the primary cleansing agent, while conditioners use cationic surfactants that bond to negatively charged hair.

Surface conditioning agents smooth the cuticle and reduce static; protein (keratin, collagen) conditioners temporarily fill gaps in damaged cortex.

Deep-conditioning treatments are applied to mid-lengths and ends, not the scalp, and are processed with heat for 10-20 minutes.

Scalp massage contraindications include contagious scalp conditions, open wounds, and recent chemical burns; massage increases circulation, not hair growth.

Hair analysis (porosity, elasticity, density) determines treatment choice: high-porosity hair absorbs and loses moisture quickly and needs protein plus moisture balance.

Dandruff (pityriasis) is treated with antidandruff shampoos containing zinc pyrithione, selenium sulfide, or ketoconazole; medicated shampoo is left on 3-5 minutes.

Over-proteinized hair feels stiff and snaps; over-moisturized hair feels mushy and limp. Balance is restored with the opposite treatment.

A patch test for hair color or lightener is applied 24-48 hours before service behind the ear or in the elbow crease.

The four basic haircut forms are solid (blunt), graduated, layered, and uniformly layered; each has a distinct elevation and distribution pattern.

Elevation of 0 degrees produces a solid form; 45 degrees produces graduation; 90 degrees produces a uniform layer; above 90 degrees creates increased layering.

Projection is the angle at which hair is held from the head; distribution is the angle relative to the curve of the head (natural, perpendicular, shifted).

A guide (section) is the length to which subsequent sections are cut; a stationary guide stays fixed, a traveling guide moves with each section.

Blunt cutting uses a horizontal cutting line; beveling or slide cutting creates soft ends; razor cutting adds texture and is not recommended on curly or fine hair.

Styling tools: blow-dryer with concentrator for smoothing, diffuser for curls, round brush for bend, thermal iron temperature should not exceed 450°F (232°C) on human hair.

Hair pressing uses a thermal pressing comb or flat iron; temperature is tested on tissue paper before application to avoid scorching.

Permanent wave chemistry: reducing agent (ammonium thioglycolate) breaks disulfide bonds; neutralizer (hydrogen peroxide or sodium bromate) rebuilds them in the new shape.

Relaxer strength: sodium hydroxide (lye) at pH 12-14, no-lye guanidine hydroxide at pH 12-13; both require a base and thorough rinsing.

Hair color classifications: temporary (large molecules, coat cuticle), semipermanent (small molecules, deposit only, no lift), permanent (oxidative dye plus developer, lifts and deposits).

Developer volumes: 10 vol (3%) deposits only, 20 vol (6%) lifts 1-2 levels, 30 vol (9%) lifts 2-3, 40 vol (12%) lifts 3-4 and is not used on the scalp.

The law of color: primary colors are red, yellow, blue; secondary are orange, green, violet; complementary colors neutralize each other (blue cancels orange).

Lightener (bleach) lifts natural pigment through stages: red, red-orange, orange, yellow-orange, yellow, pale yellow.

Relaxer retouch application begins at the scalp and works outward; virgin relaxer application starts 1/2 inch from the scalp at the nape and finishes at the scalp last.

A strand test determines processing time and product compatibility before any chemical service; record results on the client's card.

Nail structure: nail plate, nail bed, matrix, cuticle (eponychium), lunula, free edge, and nail folds.

Nail shapes: square, squoval, oval, round, and pointed; shape is chosen to match the natural nail and lifestyle.

Manicuring implements must be disinfected after each client; porous items such as emery boards and orangewood sticks are single-use or discarded.

Nail disorders: onychomycosis (fungal infection, referral required), paronychia (bacterial inflammation of nail fold), onychorrhexis (split nails), koilonychia (spoon nails).

Nail services are contraindicated on inflamed, infected, or broken skin; cosmetologists may not treat disease and must refer to a physician.

Acrylic (liquid monomer plus powder polymer) sets by exothermic polymerization; the mix ratio is about 1.5 parts powder to 1 part liquid.

Gel polish cures under UV/LED light; the base coat, color, and top coat must all be cured to avoid service breakdown.

Pedicure: soak, sanitize, exfoliate, shape, and massage; do not use credo blades or cut calluses on clients with diabetes or circulatory problems.

Skin types: normal, dry (alipidic), oily, combination, and sensitive; skin conditions include dehydration, acne, and rosacea.

Fitzpatrick skin types I-VI predict sun sensitivity; types I-II burn easily and need SPF 30 or higher.

Cleansing steps: cleanse, tone, exfoliate (1-3 times weekly), treat, moisturize, protect with SPF.

Facial massage movements follow the direction of muscle fibers and lymph flow; effleurage, petrissage, tapotement, and friction are the basic manipulations.

Extractions should be performed only on comedo-type lesions after softening with steam; never extract pustules or inflamed lesions.

Contraindications for facial services include contagious skin conditions, open lesions, recent chemical peels, and active sunburn.

Waxing: apply wax in the direction of hair growth, remove against it; do not wax over varicose veins, moles, or recently exfoliated skin.

The skin's barrier is the stratum corneum; over-exfoliation causes redness, stinging, and increased sensitivity.

Infection control levels: sanitation (reduces pathogens on surfaces), disinfection (kills most pathogens on implements), sterilization (destroys all microorganisms including spores).

Bloodborne pathogens require universal precautions: gloves, eye protection, and proper sharps disposal for any blood contact.

Implements must be cleaned with soap and water, then immersed in an EPA-registered hospital-grade disinfectant for the label contact time (often 10 minutes).

Porous items (files, buffers, cotton, wooden sticks) cannot be disinfected and must be discarded after one use.

Material Safety Data Sheets (SDS) must be kept on file for every chemical product and be accessible to employees.

Electrical safety: unplug tools before cleaning, do not use near water, and check cords for fraying; ground-fault circuit interrupters protect wet areas.

Fire safety: store flammable products in closed metal cabinets, keep a fire extinguisher rated ABC in the salon, and know exit routes.

Handwashing with soap and warm water for at least 20 seconds is the single most effective infection control measure.

The Missouri State Board of Cosmetology and Barbering regulates cosmetologists, estheticians, nail technicians, and barbers under the Division of Professional Registration.

Missouri requires completion of a board-approved cosmetology program (typically 1,500 clock hours) and passage of a written and practical examination for licensure.

Licenses must be renewed biennially; continuing education requirements and fees are set by board rule and posted by the Division.

Salon owners must obtain a salon license; a licensed salon may not employ unlicensed persons to perform services.

Disinfection requirements: implements must be cleaned and disinfected after each client with an EPA-registered disinfectant, and single-use items must be discarded.

The board may deny, suspend, or revoke a license for unsanitary practices, practicing beyond scope, or fraudulent licensure.

Client records, including chemical service records and patch test results, should be retained per board rule and made available on request.

Advertising and signage must display the licensee's name and license type; license certificates must be posted in the salon.