Page 244 - Cosmetology

PEG-40 hydrogenated castor oil. An emollient ingredient that is the polyethylene glycol (PEG) mixture of
castor oil. See polyethylene glycol (PEG) and castor oil.

PEG-80 sorbitan laurate. Mild surfactant. See surfactant.

Pelargonium graveolens oil. See geranium oil.

pellitory. See Parietaria officinalis extract.

pentadecalactone. Synthetic fragrance used in cosmetics.

pentasodium penetate. Used as a chelating agent in cosmetics to prevent varying mineral components
from binding together and negatively affecting the formulation.

Peony flower. A European flower used topically for treating a variety of skin diseases, including fissures.
Evidence of its effectiveness for these purposes is anecdotal. There is not enough known about the effects
of peony flower to substantiate its use or safety in cosmetic products.

peony root extract. There is research showing that the root of the peony plant can have anticancer
properties as well as antioxidant properties. However, there is no research showing it to have that benefit for
skin.

peppermint. Both the oil and the extract can have antimicrobial properties, but they can also have an
irritating, sensitizing effect on skin.

peptide. Proteins are comprised of a long chain of amino acids, and individual portions of proteins are
known as peptides. In the body, peptides regulate the activity of many systems. This regulation is achieved
by interaction of the peptide with a target cell. Enzymatic activity breaks proteins into peptides so they can
exert their influence on the body. Some peptides have hormonal activity, others demonstrate immune
activity, some are cell-communicating ingredients telling cells how to react and what to do, some are
believed to play a role in wound healing, and still others are thought to influence the pathology of skin
conditions such as atopic dermatitis and eczema.

Whether peptides can have benefit when applied topically to skin for wound healing, skin barrier repair, or
as disinfectants is difficult to ascertain, as they generally cannot penetrate skin and remain stable because
they are considered too hydrophilic, or water-loving. Ironically, peptides can become unstable in water-
based formulas. Further, because peptides are vulnerable to the presence of enzymes, when peptides are
absorbed, the abundant enzymes present in skin can break the peptides down to the point where they have
no effect. However, the latest research is examining how different types of synthesized peptides can enter
the living membrane of cells and, more interesting, transport biologically active ingredients to these cells.
Some of these peptides have demonstrated a remarkable anti-inflammatory effect. Creating specific peptide
chains in the lab and then attaching a fatty acid component to them allows peptides to overcome their
inherent limitations: absorbing and staying stable. Lab-engineered peptides appear to have the kind of
efficacy and benefit that goes beyond the skin’s surface, but more conclusive, long-term research is
essential to understanding what, if anything, is really taking place. It is reasonable to assume that as
synthetic peptide technology broadens, we will see more options for use in skin-care products promoting
anti-aging properties, specifically, tissue regeneration.

In order for these specialized peptides to exert a benefit beyond that of a water-binding agent, three criteria
must be met: the peptides must be stable in their base formula, they must be paired with a carrier that
enhances absorption into the skin, and they must be able to reach their target cell groups without breaking
down. Achieving this goal is no easy feat, but one that cosmetic scientists are predicting will have significant
potential in the realm of anti-aging skin-care ingredients.

perfluoropolymethylisopropyl ether. Film-forming agent. See film-forming agent.

Perilla ocymoides oil. Derived from the seeds of the Perilla ocymoides plant. Perilla contains multiple
flavones and the oil is high in alpha-linolenic acid. It has antioxidant and anti-cancer properties; however it
may also be a significant skin irritant.

periwinkle extract. There is no research showing this extract to have benefit for skin. It is not to be