Page 273 - Cosmetology

Ximenia americana oil. Plum oil; it can have emollient properties.

xylitol. See sorbitol.

xylose. Form of sugar. Similar to other sugars, xylose has water-binding properties for skin.
Y

yarrow extract. There is little research showing yarrow extract to have benefit for skin. What studies do
exist were done in vitro and indicate that it may have anti-inflammatory properties

yeast. Group of fungi that ferment sugars. Yeast is a source of betaglucan, which is considered a good
antioxidant. A simple Internet search for brewer’s yeast (Latin name Saccharomyces cerevisiae), brings up
over 85,000 references. Yeasts are basically fungi that grow as single cells, producing new cells either by
budding or fission [splitting]. Because it reproduces well, Saccharomyces cerevisiae is the organism that is
most widely used in biotechnology. Nevertheless, some forms of yeast are human pathogens, such as
Cryptococcus and Candida albicans.

In relation to skin, there is limited information about how Saccharomyces cerevisiae may provide a benefit.
Live yeast-cell derivatives have been shown to stimulate wound healing (Source: Archives of Surgery, May
1990, pages 641–646), but research like this is scant. Most of what is known about yeast is theoretical, and
is about yeast’s tissue-repair and protective properties.

yellow lupine. See Lupinus luteus seed extract.

yerba mate extract. Used for the preparation of the most popular tea-like beverage of South America. It has
anti-inflammatory and antioxidant properties.

ylang-ylang. Fragrant, volatile oil that can also be a skin irritant. See volatile oil.

yogurt. There is no research showing yogurt to be effective when applied topically on skin.

yucca extract. Plant extract that can have anti-inflammatory benefits.
Z

Zanthoxylum alatum extract. Has no known benefit for skin when applied topically

Zanthoxylum piperitum. See Szechuan pepper.

zedoary oil. Fragrant oil that can be a skin irritant, though there is also research showing that components
of zedoary can have anti-inflammatory and antioxidant properties

zeolite. One of a group of minerals used as an absorbent in cosmetics. It has been shown to have
anticancer properties

zinc. There is growing evidence that zinc can be a significant anti-irritant and antioxidant. It also can have
anti-acne benefits when combined with a topical antibiotic such as erythromycin. Taken orally, zinc may
have positive effects for wound healing and other health benefits

zinc carbonate. See calamine.

zinc gluconate. A combination of zinc with a form of glucose (a sugar) that is commonly used in cold
lozenges for its antiviral effects. A study reported in Dermatology (2001, volume 203, issue 2, page 40)
evaluated “the place of zinc gluconate in relation to antibiotics in the treatment of acne vulgaris. Zinc was
compared to minocycline [an antibiotic] in a multicenter randomized double-blind trial. 332 patients received
either 30 milligrams elemental zinc or 100 milligrams minocycline over 3 months. The primary endpoint was
defined as the percentage of the clinical success rate on day 90….” The study concluded that “Minocycline
and zinc gluconate are both effective in the treatment of inflammatory acne, but minocycline has a superior
effect evaluated to be 17% in our study.” Whether or not this relates to topical applications is unknown. Note:
High doses of zinc can be toxic. Avoid taking more than 100 mg of zinc per day from a supplement

zinc oxide. Inert earth mineral used as a thickening, whitening, lubricating, and sunscreen ingredient in
cosmetics. One manufacturer of zinc oxide has heavily promoted this ingredient as being the only option for
broad-spectrum sun protection, but this has not been proven by other independent research. Along with