▶ Previous Artlcle : #2-1. Effect and types of whitening agents
Research trends of global cosmetic manufacturers
Research trends of global cosmetic manufacturers in the field of whitening products from 2008 can be summarized as follows.
LOREAL investigated skin characteristics of different races and behavior of melasma lesions. As part of this effort, they performed a study on pH and pigmentation and published the results showing the correlation between the pH changes of melanocytes and pigment lesions. They came to a conclusion that cAMP increase caused by alpha-MSH raises the pH level of melanosome. Examining the skin characteristics of Caucasians and African Americans, the length of dermoepidermal junction in a black person was three times longer than that of a Caucasian and cytokine expression differed between races. In a study on age- and race-related changes in skin tone and consistency, they examined skin color and consistency in women of four races living in the same city and found the skin tone and consistency changed depending on the race and age.
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A study examining physiological changes of melasma lesions found that destruction of skin barrier led to increased transepidermal water loss and reduction in skin hydration and stratum corneun thickness. Also, erythema and melanin index increased. Cystinosin, a regulator of pH levels in melanosome was first discovered.
P&G examined the relationship between age recognition and distribution of skin pigments and facial features. They found the pigment distribution and features of the face greatly influenced recognition of a woman’s age and health. They also performed a clinical study to analyze principles of human recognition of brightness of facial skin and showed the correlation.
Evaluation of degradation of melanosome in keratinocytes in dark and light skin revealed that melanosome was more easily degraded in light skin compared to dark skin. Enzymes that disintegrate melanosome have been discovered and comparison of enzyme expression in different skin colors showed that keratinocytes in light skin produced cathepsin L2 significantly more compared to dark skin. Here, production of cathepsin L2 was found to be a key factor in determining the skin tone.
BEIERSDORF studied the impact of long-term exposure to ultraviolet rays at molecular level. Melanogenic factors, growth factor/receptor, adhesion molecules, and cell cycle protein were examined after repeated irradiation of UV rays for 1-4 years. It was found that only TYR, MART1, and endothelin receptor increased whereas the rest remained unchanged. A study examining pigmentation mechanism of neuregulin-1 (NRG-1) expressed in fibroblasts reported that NRG-1 expression increased in dark skin.
A study on DNA damage and pigmentation caused by different UV rays investigated if a correlation existed between irradiation of UV rays with differing wavelengths and production of cyclobutane pyrimidine dimmers and melanin. Results showed that UVB did not promote production of cyclobutane pyrimidine dimmers but increased production of melanin. UVA did not promote production of melanin. However, UVA has no protective action due to increased cyclobutane pyrimidine dimmers and UVB was found to be a molecular-biological promoter of DNA photodamage and melanin synthesis.
JOHNSON & JOHNSON studied pigmentation caused by visual light and found that visual light causes more serious pigmentation compared to UVA. They also studied skin aging from visual light and visual light causes reactive oxygen species and expression of MMP-1 as much as UV.
ESTEE LAUDER proposed a new theory on the malanogenisis of melanocytes and melanin transfer machanism. They found Rab27A and melanoreglin to be two important genes involved in melanosome transfer. AMORE PACIFIC studied specific genes of melasma lesions and found WIF-1, PDZK1, and H19 to be representative genes causing melasma. Expression of H19, WIF-1 is reduced in melasma whereas expression of PDZK1 is increased. Moreover, a study on pigment modulation by immune factors found that the whitening effect of Kojic acid inhibits tyrosinase activation as well as increases IL-6 in keratinocytes to brighten the skin tone. Moreoever, IL-4 has been found to inhibit melanin production.
Ingredients and effect of popular whitening products
The most popular skin whitening cosmetic products are as follows.
LANCOME newly released Blanc Expert, Derm Crystal, and Crystal Brightness Activating Essence and advertise their effect on giving the skin crystal brightness. Dermal fibers are oxidized from aging or external stress stimuli and lose clarity which result in a darkened and dull skin tone. The clarity of dermal fibers can be improved to provide translucent appearance of the skin. Salicylic acid removes dead keratinocytes and actyl-P, a vitamin C derivative, inhibits epidermal pigmentation. Dermactyl complex earned from bean and sunflower extracts promotes collagen generation and inhibits yellow collagen generation to create a brightened tone.
SK-II introduced Cellumination Essence EX, Spot Specialist Concentrate. Their marketing message is that these products help skin appear illuminant and clear even from a distance of 20 cm. They contain Aura Pixel Bright Cocktail with sepiwhite, Pitera, niacinamide, Talapewhite, etc. Clinical data comparing 1% sepiwhite with 2% hydroquinone show that the two ingredients brought similar brightening effect and skin barrier improvement.
DIOR released White Reveal Ultra Purifying Fluid claiming its effect on bringing healthful and translucent skin tone. The main ingredient of this product is Iceland glacier water which is known to reflect light and promote protein synthesis.
KIEHL’S presented Clearly corrective dark spot solution and promoted its effect on creating spotless, bright skin tone. Main ingredient is actyl-P, a 3-O-ethyl ascorbic acid. Actyl-P has the smallest molecular size among vitamin C derivatives and boasts high permeability and stability. When metabolized in the body, it works as vitamin C to inhibit tyrosinase and melanin synthesis. It also promotes synthesis of type 1 collagen, prevents DNA damage and has antioxidative action.
There is no whitening agent that offers a perfect solution to pigment problems. However, various modalities are being developed to improve skin clarity in a safe and reliable way. In this light, a dermatologist plays an increasingly important role in helping patients to select the best treatment or product.
-To be continued-
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