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Arbutin
Arbutin is a naturally occuring derivative of hydroquinone found in the leaves of cranberry, bearberry, and blueberry shrubs, most types of pears, and many other plants. Arbutin may inhibit melanogenesis by affecting tyrosinase activity.

Arbutin has been used in the treatment of disorders of hyperpigmentation such as postinflammatory hyperpigmentation caused by acne, trauma, allergic reactions, infections, injuries, phototoxic reactions, reactions to medications, reactions to cosmetics, and inflammatory diseases.

Arbutin concentration protocols for skin whitening have not yet been established. Low concentrations have no effect, while high concentrations of about 5% or more can be as irritating as hydroquinone and may potentially result in unexpected hyperpigmentation (darkening).

Apha-Arbutin is a powerful, yet gentle, lightening agent derived from the Bearberry tree. Alpha-Arbutin brings all the benefits of strong melanin inhibitors like
hydroquinone without the strong odor, toxicity, and potential side effects. Alpha-Arbutin is quickly becoming the logical alternative to harsh skin lightening chemicals.

Most skin-lightening treatments, which can reduce or block some amount of melanin production, are aimed at inhibiting tyrosinase. Many treatments use a combination of topical lotions or gels containing melanin-inhibiting ingredients along with a sunscreen, and a prescription retinoid. Depending on how the skin responds to these treatments, exfoliants — either in the form of topical cosmetic or chemical peels — and lasers may be used. New development using LED systems are also showing good results.

Pre-melanin synthesis TretinoinResearch has shown that the use of Tretinoin (also known as all-trans retinoic acid) can only be somewhat effective in treating skin discolorations.

Users of tretinoin have to avoid sunlight, as the skin can tan. Using tretinoin makes the skin more sensitive to UVA and UVB rays.

During melanin synthesis HydroquinoneMain article: Hydroquinone
In medical literature, hydroquinone is considered the primary topical ingredient for inhibiting melanin production.Its components have potent antioxidant abilities.Topical hydroquinone comes in 2% (available in cosmetics) to 4% (or more) concentrations (available from a physician or by prescription), alone or in combination with tretinoin 0.*5% to 0.1%. Research has shown hydroquinone and tretinoin to prevent sun- or hormone-induced melasma.

Hydroquinone is a strong inhibitor of melanin production, meaning that it prevents skin from making the substance responsible for skin color. Hydroquinone does not bleach the skin but lightens it, and can only disrupt the synthesis and production of melanin hyperpigmentation. It has been banned in some countries (e.g. France) because of fears of a cancer risk.

Some concerns about hydroquinone's safety on skin have been expressed, but the research when it comes to topical application indicates negative reactions are minor or a result of using extremely high concentrations or from other skin-lightening agents such as glucocorticoids or mercury iodine. Any perceived risk is most likely applicable for African women.Hydroquinone has been shown to cause leukemia in mice and other animals. The European Union banned it from cosmetics in ***1, but it shows up in bootleg creams in the developing world. It is sold in the United States as an over-the-counter drug, but with a concentration of hydroquinone not exceeding 2 percent.

Because of hydroquinone's action on the skin, it can be irritant, particularly in higher concentrations of 4% or greater and predictably when combined with tretinoin. Some medications have been created that combine 4% hydroquinone with tretinoin and a form of cortisone. The cortisone is included as an anti-inflammatory. The negative side effect of repeated application of cortisone is countered by the positive effect of the tretinoin so that it does not cause thinning of skin and damage to collagen.Safer alternatives are more expensive but are available.

ArbutinSome of alternative lighteners are natural sources of hydroquinone. They include Mitracarpus scaber extract, Uva ursi (bearberry) extract, Morus bombycis (mulberry), Morus alba (white mulberry), and Broussonetia papyrifera (paper mulberry). All of these contain arbutin (technically known as hydroquinone-beta-D-glucoside), which can inhibit melanin production. Pure forms of arbutin are considered more potent for affecting skin lightening (alpha-arbutin, beta-arbutin, and deoxy-arbutin). Beta-Arbutin is also known by its more common name of Bearberry extract

Arbutin is derived from the leaves of bearberry, cranberry, mulberry or blueberry shrubs, and also is present in most types of pears. It can have melanin-inhibiting properties.Arbutin and other plant extracts are considered safe alternatives to commonly used depigmenting agents to make the skin fairer. Medical studies have shown the efficiency of Arbutin for skin lightening. There are patents controlling its use for skin lightening. Arbutin actually exists in two conformations, alpha and beta. The alpha conformation offers higher stability over the beta conformation and is the preferred form for skin lightening indications.

Kojic acidKojic acid is a by-product in the fermentation process of malting rice for use in the manufacturing of sake, the Japanese rice wine. Some research shows kojic acid to be effective for inhibiting melanin production.However, kojic acid is an unstable ingredient in cosmetic formulations. Upon exposure to air or sunlight it can turn brown and lose its efficacy. Many cosmetic companies use kojic dipalmitate as an alternative because it is more stable in formulations. However, there is no research showing kojic dipalmitate to be as effective as kojic acid, although is it a good antioxidant. Further, some controversial research has suggested that kojic acid may have carcinogenic properties in large doses. Other further studies show that kojic acid is not carcinogenic, but can cause allergic contact dermatitis and skin irritation.

Azelaic acidAzelaic acid is a component of grains, such as wheat, rye, and barley. It is applied topically in a cream formulation at a ****0% concentration. Azelaic acid is used to treat acne, but there also is research showing it to be effective for skin discolorations. Other research also indicates azelaic acid may be an option for inhibiting melanin production.

Vitamin CVitamin C and its various forms (ascorbic acid, Magnesium ascorbyl phosphate, etc.) are considered an effective antioxidant for the skin and help to lighten skin.One studyfound it raises glutathione levels in the body. Another study found that brownish guinea pigs given vitamin C, vitamin E and L-cysteine, simultaneously, lead to lighter skin.

Cinnamomum subaveniumCinnamomum subavenium, a Chinese herb, has been suggested for use as a skin whitening agent. The plant contains substances which inhibit production of tyrosinase an enzyme which catalyzes the production of melanin. The herb has not been established as either effective or safe but is being researched by Hui-Min Wang and his colleagues at Kaohsiung Medical University in Taiwan where experiments shown that it was effective at causing Zebrafish to lose their stripes.