How Do Skin Lighteners Get Rid of Discoloration?

ANTIOXIDANT PROTECTION

• Antioxidants help prevent free radicals from activating tyrosinase. This is the enzyme that initiates the production of melanin pigments. ^(xi.70)
• Protects existing melanin from oxidation by UV radiation. ^(xi.70)
• Stimulates natural antioxidants in the body (e.g., GSH). ^(xi.71)

Examples of skin lighteners that work this way:

• Certain flavonoids (e.g., proanthocyanidins from the skin of grapes) ^(xi.70, 71)
• Pine bark extract ^(xi.71)
• Pomegranate ^(xi.71)
• Vanillic acid ^(xi.71)
• Vitamin C ^(xi.70)
• Vitamin E ^(xi.70)

GENERATING FREE RADICALS

• Damages cell membranes and interferes with melanocyte cell processes. ^(xi.70)
• Depresses levels of natural antioxidants. ^(xi.70)
• Breaks down melanosomes and tyrosinase proteins. ^(xi.70)
• Can lead to permanent loss of melanocyte skin cells, especially in people with fair skin. ^(xi.70)

Examples of skin lighteners that work this way:

• Flavonoids ^(xi.70)
• Hydroquinone ^(xi.70)

INHIBITING TYROSINASE ACTIVITY

• Some compounds prevent the synthesis of tyrosinase. ^(xi.71)
• Compounds that bind to tyrosinase prevent it from initiating melanin production. Substances that work in this fashion are considered safer than those that damage melanocytes. ^(xi.70)
• Others bind with molecules tyrosinase needs to start the process of making melanin. ^(xi.70)

Examples of skin lighteners that work this way:

• Aloesin (from Aloe) ^(xi.69)
• Alpha-hydroxy acids ^(xi.70)
• Arbutin ^(xi.70)
• Azelaic acid ^(xi.70)
• EGCG and other catechins from tea ^(xi.71)
• Licorice ^(xi.70)
• Linoleic acid ^(xi.70)
• Milk thistle ^(xi.71)
• Mulberry extract ^(xi.69)
• Resveratrol ^(xi.70)
• Vanillic acid ^(xi.71)

BLOCKING DOPACHROME TAUTOMERASE ENZYME ACTIVITY

• Prevents transformation of precursor compounds further along in the production of melanin pigments. ^(xi.70)

Examples of skin lighteners that work this way:

• Kojic acid ^(xi.70)

COPPER CHELATION

• Tyrosinase uses copper and oxygen to begin converting L-tyrosinase to melanin. ^(xi.69)
• Compounds that bind or get rid of copper limit tyrosinase's activity. ^(xi.70)

Examples of skin lighteners that work this way:

• Flavonoids ^(xi.70)
• Kojic acid ^(xi.70)

BLOCKING MITF AND AHR

• Blocking the MITF transcription factor prevents activation of the gene mainly responsible for melanin production. ^(xi.70)
• Damage to skin cell DNA caused by UV radiation or chemical toxins (e.g., dioxin and PCBs) can trigger melanin production. Inhibiting the aryl hydrocarbon (AHR) transcription factor can help prevent this. ^(xi.64, 65)

Examples of skin lightening compounds that work this way:

• Curcumin (AHR and MITF) ^(xi.65, 71)
• EGCG from tea (MITF) ^(xi.71)
• Myricetin (AHR) ^(xi.65)
• Quercetin (AHR) ^(xi.65)
• Resveratrol (both MITF and AHR) ^(xi.65, 70)
• Retinoid acids (MITF) ^(xi.70)

ACTIVATION OF PPAR-γ

• Inhibits production of tyrosinase by reducing levels of MITF. ^(xi.70, 72)

Examples of skin-lightening compounds that activate PPAR-γ include:

• Curcumin ^(xi.73)
• Octadecenoic acid ^(xi.70)
• Rumex occidentalis extract ^(xi.70)
• Ar-turmerone ^(xi.43)

HORMONE SUPPRESSION

• Prevents activation of the gene mainly responsible for melanin production. ^(xi.70)

Examples of compounds that can help lighten skin this way:

• Curcumin (α-MSH and ACTH) ^(xi.74, 75)

INTERFERING WITH MOVEMENT OF MELANIN INTO KERATINOCYTES

• Compounds that inhibit protease-activated receptor 2 (PAR-2) proteins prevent keratinocytes from ingesting melanosomes. ^(xi.70)

Examples of skin lighteners that block movement of melanin between melanocytes and keratinocytes by inhibiting PAR-2 or other mechanisms include:

• Lectins ^(xi.70)
• Niacinamide ^(xi.70)
• Soy extracts ^(xi.70)

EXFOLIATION

• Removes outer layer of keratinocytes that contain melanin. ^(xi.70)

Examples of skin lighteners that work this way:

• Alpha-hydroxy acids ^(xi.70)
• Linoleic acid ^(xi.70)
• Kojic acid ^(xi.70)
• Retinoic acid ^(xi.70)
• Salicylic acid ^(xi.70)