The ShampooGarage Glossary

The outermost layer of the hair shaft, made up of overlapping scales. Healthy cuticles lie flat; damaged ones are raised or missing.

The middle layer of the hair shaft containing melanin (color) and keratin. Chemical processes like coloring and perming affect this layer.

Washing hair with conditioner instead of shampoo. Popular in the natural hair community for maintaining moisture in curly and coily hair types.

Using a clarifying shampoo to remove product buildup, mineral deposits, and excess oils. Should be done every 2 to 4 weeks depending on product use.

A conditioning treatment left on hair for 15 to 30 minutes (often with heat) to penetrate the cortex and restore moisture and elasticity.

The number of individual hair strands per square inch of scalp. Low density = fewer strands; high density = more strands.

Ingredients that soften and smooth the hair by filling gaps in the cuticle. Oils and butters are natural emollients.

Hair's ability to stretch and return to its original length without breaking. Healthy hair stretches noticeably when wet and springs back.

Refers to the diameter of individual hair strands, not the overall density of hair. Fine hair has a smaller diameter; coarse hair has a larger one.

Ingredients that draw moisture from the air into the hair. Common humectants include glycerin, hyaluronic acid, and aloe vera.

Damage caused by repeated swelling and contracting of the hair shaft from excessive moisture. Common in high porosity hair.

The fibrous protein that makes up most of the hair shaft. Keratin treatments temporarily smooth the cuticle by infusing additional protein.

Liquid, Oil, Cream, a moisture layering technique for natural hair. Apply in this order to lock in hydration. Best for high porosity hair.

Liquid, Cream, Oil, a variation of the LOC method where cream is applied before oil. Often better for low porosity hair.

The innermost layer of the hair shaft, present in thick hair but often absent in fine hair. Its function is not fully understood.

Hair's ability to absorb and retain moisture, determined by the state of the cuticle layer. Low porosity = closed cuticles; high porosity = open/damaged cuticles.

Preservatives used in cosmetics to prevent microbial growth. Some consumers avoid them due to concerns about hormonal disruption, though evidence is limited.

A deep conditioning treatment that infuses hydrolyzed proteins into the hair to temporarily repair damage and add strength.

A technique for drying curly hair using a microfiber towel or T-shirt to reduce frizz and enhance curl definition.

Hair and scalp have a natural pH of 4.5 to 5.5 (slightly acidic). Products outside this range can disrupt the cuticle and cause damage.

The float test (drop a strand in water and watch whether it sinks) is popular but unreliable, because oil, product, and surface tension change the result. Wet-out time, drying time, and how products sit on the hair are better guides.

Surfactants (cleansing agents) like SLS and SLES that create lather. Effective but can strip color and natural oils. Sulfate-free formulas use gentler alternatives.

Synthetic polymers that coat the hair shaft for shine and smoothness. Water-soluble silicones (often with PEG- or PPG- in the name) rinse out easily; others require sulfates to remove.

The natural oil produced by sebaceous glands in the scalp. Sebum moisturizes and protects the hair shaft but can cause greasiness if overproduced.

Testing a new chemical treatment on a single strand before applying to the full head to check for adverse reactions.

The scientific study of hair and scalp health. A trichologist is a specialist who diagnoses and treats hair and scalp disorders.