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WHAT'S AT STAKE? "The use of hydroquinone (HQ) in hyperpigmentation treat- ments is a double-edged sword," says John Kulesza, president and senior formulating chemist, Young Pharmaceuticals (young- pharm.com). "While it is highly effective, it is chemically similar to benzene and phenol, two toxic substances. Tyrosine used by melanocytes to produce melanin has the same six carbon molecule ring structure as hydroquinone. It is a competitive antagonist—fi tting into the melanocyte receptor but unable to be made into melanin—which is one of the things that makes HQ so effective. Of course, you have to keep using HQ or the pigment returns." Therein lies the major problem, says Felipe Jimenez, PhD, chief scientifi c offi cer, Envy Medical (envymedical.com), who has worked for many years on skin lightening formulations, fi rst with Obagi Medical and then putting together the Lumixyl Sys- tem based on discoveries made at Stanford University. "When someone uses HQ for years and wants to stop, there is a high probability he or she will experience a rebound of hyperpig- mentation that can be worse than the original problem. The hyperpigmentation will return no matter what product you use, but the question is, to what degree? Without the HQ killing melanocytes, stem cells often produce an abundance of new melanocytes that quickly produce even more pigment than the individual might have had originally." According to chemist Araz Bidari, head of research and development, Hale Cosmeceuticals (halecosmeceuticals.com), cytotoxicity is only one of the problems with HQ. "Several re- spected scientists have written papers regarding the carcinogen- ic potential of HQ, with one 2005 document from the Journal of the European Academy of Dermatory & Venereology con- cluding: 'The risks of long-term effect of topically applied HQ may no longer be ignored. Based on recent evidence of the potential risks, which are higher than has been assumed up until now, we plead that the use of HQ as a skin lightening agent be stopped completely'," he relates. The European Union banned HQ use in cosmetics in 2001 and other countries, including Japan and Australia, have restricted its use. Carl Thornfeldt, MD, a practicing dermatologist and founder and CEO of Episciences and Epionce (epionce.com), believes that HQ's sucess rates don't justify its use. "Early in my practice I thought HQ was an OK treatment," he says, "but then I looked at its success rates. In most studies success rates range from 36% to 51%; the highest rate in any study was 63%. Couple that with irritation rates, which are sometimes as high as 83%, and I conclude that it is not a good drug. There must be a bet- ter way to treat hyperpigmentation." Let's be clear, the majority of dermatologists still support the use of hydroquinone under medical supervision. Still, even staunch proponents like Zein Obagi, MD, are expressing con- cern about the overuse of HQ. In an article in the March 2014 issue of Practical Dermatology, Dr. Obagi said that based on current research he believes HQ should not be prescribed for more than four to fi ve months consecutively and that patients should then cycle off the drug for two to three months before continuing its use. HQ ALTERNATIVES The search for alternatives to hydroquinone has led to some promising discoveries. Following are some of the best-known cosmetic ingredients used in skin lightening/brightening products: Arbutin, derived from bearberry, blueberry and cranberry plants is a glycosylated form of HQ, with varying degrees of toxicity, that inhibits tyrosinase and interferes with melanosome production. Deoxyarbutin is a new synthetic derivative of arbutin with much lower cytotoxicity. Azelaic acid, a naturally occurring, non- toxic dicarboxylic acid, is derived from grains, such as wheat, rye and barley. Though it is primarily used to treat rosacea and acne, it also inhibits tyrosinase. "It selectively infl uences the mechanism of hyperactive and abnormal melanocytes, but minimally infl uences normal skin pigmentation," says Bidari. "Although not all researchers are in agreement with the therapeutic effi cacy of azelaic acid, it has been reported to be effective in treatment of melasma and acne. A 24-week multicenter, controlled, double-blind clinical trial of 329 women compared the effi cacy of a 20% az- elaic acid cream to a 4% HQ cream in treating melasma. The authors reported no signifi cant differences in the results: 65% of the patients treated with azelaic acid achieved good to excellent results compared to 73% of patients THE BEST OFFENSE IS A GOOD DEFENSE Treating pigmentation problems is complex because of the range of skin types—very fair to very dark—and the types of problems, which range from post-infl ammatory hyperpigmentation to chronic melasma. The most common cause of unwanted dark spots, though, is sunburn or excessive UV exposure. Fortunately, this is largely preventable with today's sophisticated sunscreens. All of the experts for this article stressed the need to ensure that patients being treated for pigmentation problems, whether with HQ or non-HQ prod- ucts, use sun protection every day. "This means SPF 50 and wearing hats and seeking shaded areas. If patients are unwilling to give up sun, then I am honest in telling them that it may not be worth investing in treatment because it may not work and will certainly come back," says Atlanta dermatologist Chynna Steele, MD. "Even light from a light bulb can stimulate melanocytes," says John Kulesza, president and senior formulating chemist, Young Pharmaceuticals (youngpharm.com). "It is vitally important to reduce light stimulation to fi ght hyperpigmentation. One of the best ways to do that is with a concealor which blocks all light in the visible range and helps calm overactive melanocytes." 36 MAY/JUNE 2014 | Med Esthetics CYCLING OFF HYDROQUINONE C y c l i n g O f f M E D 5 - 6 1 4 . i n d d 3 6 Cycling Off MED5-614.indd 36 4 / 1 7 / 1 4 2 : 3 5 P M 4/17/14 2:35 PM