Beauty Glossary: P

PABA (para-aminobenzoic acid) - a chemical sunscreen that blocks UVB rays. Its popularity has waned because it can irritate the skin.

Padimate-0 - a PABA derivative.

Panthenol - one of the B vitamins used in hair conditioners, it fills in cracks in the hair shaft to strengthen the hair.

Papain - an enzyme derived from papaya that is used to exfoliate the skin.

Paraffin - wax used at a spa to exfoliate hands and feet.

Parsol 1789 (avobenzone) - an ingredient in sunscreens that blocks UVA radiation.

Pediculosis - infestation of head lice.

Peptides - a group of two or more amino acids used in conditioners and shampoos that form a layer on the hair shaft to make the hair look thicker.

Petrolatum - a solid, waxy petroleum derivative commonly known as petroleum jelly, paraffin jelly or Vaseline.

Petroleum products - the words paraffin, propylene glycol, ozokenite, isopropyl myristate, or anything with butyl or propyl in the name indicate that the product is made from petroleum.

pH - the measure of acidity or alkalinity of a substance, which is graded on a scale of 1 to 14. A pH 7 is neutral; below 7 is acidic; above 7 is alkaline.

Phenolic acid - a coal-tar derivative also known as carbolic acid that is used in deep phenol peels.

Phytotherapy - the therapeutic use of plants in skin or hair care products.

Placenta extract - a substance used in hair and skin care products derived from human or animal placenta.

Polyethylene glycol (PEG) - a softening ingredient used in cosmetic creams.

Poly-hydroxy acids (PHAs) - similar to alpha-hydroxy acids, but from a different source, they are gentler but not as effective.

Polymers - compounds commonly used to bind styling products to the hair and sunscreens to the skin.

Polysorbate 20 - a substance used in shampoos and cleansers to build lather.

Potassium hydroxide - an alkali used in soap and shampoos.

Poultice - a warm compress applied to irritated or inflamed areas of the body.

Propellant - the primary delivery system for aerosol hairsprays and mousses; examples include butane, isobutane, propane, and hydrofluorocarbon.

Propylene glycol - a humectant that is good for people with oily skin.

Propylparaben - a preservative.

Proteins - derived from synthetic and natural sources such as collagen, milk, keratin, and silk, these are found in hair conditioners and hair spritzes. They add shine and body to the hair and help smooth split ends; examples include hydrolyzed animal protein, hydrolyzed
keratin, hydrolized soy protein, hydrolyzed whole-wheat protein, and silk amino acids.

Pro-vitamins - Vitamin A, B, and E derivatives used in conditioners to strengthen the hair shaft. Common examples include biotin, panthenol, and tocopherol acetate.