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Exploring the Clinical Benefits of PHAs

An interview with BARBARA GREEN, R.Ph., M.S.

Scientists have taken the benefits of alphahydroxy acids (AHAs) to a higher level with the development of polyhydroxy acids (PHAs)—a kinder, more gentle group of hydroxy acids that has been shown to provide exceptional skin benefits without the irritation sometimes associated with AHAs.

PHAs were identified and patented for skin application by the NeoStrata Company where Barbara Green serves as the company's director of Technical and Consumer Affairs. With a background in pharmacy and chemistry, Ms. Green has been published in numerous scientific papers and is a sought-after speaker on skin care issues and new ingredient technologies.

Nu Skin recently interviewed Ms. Green about the evolution of PHAs, as well as the latest clinical information on these beneficial acids:

NS: For the past several years, we've seen AHAs as featured ingredients in many moisturizers and skin care treatments. What can you tell us about AHAs and how they work?
BG: AHAs were first discovered by Dr. Eugene Scott and Dr. Ruey Yu. They were looking for natural, nontoxic compounds that could positively influence cell turnover and help regulate skin formation. Their first intention was to correct ichthyosis (severely dry skin), and they later discovered the benefits of AHAs for photoaged skin. Today, AHAs are recognized in the same category as retinoids and sunscreens as one of the few ingredient technologies with proven antiaging benefits.

NS: What are PHAs?
BG: A PHA is an AHA, but slightly larger in size with more hydroxy groups (poly means multiple). Some examples of PHAs are sugar acids—lactobionic acid comes from oxidized lactose (milk sugar) and gluconolactone comes from oxidized glucose (a natural sugar found in the human body).

NS: What are the similarities and differences between AHAs and PHAs?
BG: PHAs are similar to AHAs in that they have both been shown in clinical studies to have anti-aging benefits when topically applied to the skin. AHAs contain only one hydroxyl group and have been known to produce stinging, burning, and tingling sensations in some people. In contrast, PHAs have multiple hydroxyl groups—providing the same age defying benefits as conventional AHAs, but without the irritation. Even very sensitive skin types can tolerate PHAs, including atopic and rosacea skin. It is thought that the gentle, nonirritating action of PHAs may be partially related to a larger molecular composition than that of conventional AHAs. Larger molecules are believed to penetrate the skin at a slower rate, causing less irritation. This reduced irritation, coupled with natural antioxidant properties, gives PHAs a gentle, competitive edge over other anti-aging treatments.

NS: How do PHAs address the factors that can accelerate the aging process?
BG: In clinical studies, PHAs have been shown to have numerous anti-aging benefits, including enhancing cell turnover; improving skin clarity and brightness; reducing the appearance of fine lines, wrinkles, and pore size; and enhancing skin smoothness and elasticity. PHAs are also known to chelate excess iron in the skin, reducing potential oxidative damage.

NS: What is chelation?
BG: Chelation is a term used to describe the process of trapping a material, such as a metal, rendering it biologically inactive. For example, iron overdoses are treated with chelation therapy to allow the body to trap and remove the excess iron.

NS: How does iron chelation benefit the skin?
BG: Iron is an oxidation-promoting metal that occurs naturally in skin. Excess iron is believed to cause toxicity due to free radical damage induced by iron. For example, UV sun exposure and iron are thought to be synergistic in the induction of skin pigmentation—a common sign of photoaging in skin. The use of chelating agents such as gluconolactone and lactobionic acid helps capture free iron in skin, thereby reducing its potential to promote oxidative damage.

NS: We were interested to discover that lactobionic acid is used in transplant organ preservation. What are the nurturing properties that make lactobionic acid an efficacious ingredient in preservation fluid for transplant organs?
BG: Lactobionic acid is a major constituent in some organ transplantation preservation fluids because it can suppress tissue damage caused by oxygen radicals. This allows organs to be preserved outside of the body for up to two days. Similarly, many of the skin damaging effects of the sun occur following the creation of oxygen radicals in response to sunlight. Lactobionic acid is thought to nurture the skin, trapping harmful materials that promote oxidative damage following sun exposure. Additionally, the safe use of lactobionic acid on organs demonstrates its gentleness for use on skin.

NS: What are the benefits of gluconolactone?
BG: Gluconolactone is highly moisturizing with antioxidant effects. It is gentle and nonirritating yet provides significant anti-aging benefits. It has been shown to nurture skin by enhancing its natural barrier function.

NS: What other benefits of PHAs do you find impressive?
BG: One of my favorite features is the enhanced hydration and gentleness that accompanies the anti-aging effects. You no longer have to give up soft, moisturized skin to have anti-aging benefits. Additionally, lactobionic acid has an interesting film-forming effect due to its tremendous ability to bind water. This translates into a unique, silky feel in products containing PHAs.