skin lightening agents

1. SKIN LIGHTENING &
BLEACHING CREAMS
1
-Radhika Ramchandrabharath
14OIL1017

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Introduction
• Since times immemorial fair skin is associated with
lineage of nobility, aristocracy and wealth. Regardless of
this idiosyncrasy, majority of the people have a penchant
to possess an even, unblemished skin tone.
• So man has made attempts to artificially colour, bleach and
in other ways alter the normal appearance of his skin.
• This need is fulfilled by the cosmetic industry with a huge
plethora of products specially offering skin lightening and
bleaching properties. These products contain special active
ingredients which lightens skin, thus giving an enhanced
whiter appearance.

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• Skin lightening creams – are also known as
bleaching creams, skin whiteners, skin brighteners or
fading creams.
• These work by reducing a pigment called “melanin”
in the skin.
• Most people who use lighteners do so to treat skin
problems such as freckles, age spots, acne scars,
discoloration related to hormones or lighten skin
tone.

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To understand this, we first need to understand
the skin structure synthesis of melanin in the
skin.
Skin is composed of 2 main layers – “Epidermis” and “Dermis”
Skin color results from the presence and proportion of several
chromophores like Oxyhaemoglobin (bright red), Reduced Haemoglobin
(Bluish red) and bilirubin(yellow) are found in small blood vessels of
dermis, whereas Eumelanin (deep brown or black) and Phaeomelanin
(Yellowish to reddish brown) and some Carotenoid pigments are the
main pigments in Epidermis.

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Melanin is a pigment that is produced by cells known as
melanocytes in the skin and impart colour to the skin.
The control of melanin production is due to both direct stimulatory
effect of ultraviolet light and a hormone MSH, secreted by anterior
pituitary gland.
Melanin comes in two basic forms and can range from yellowish-
red to dark brown. Eumelanin is the most common form of
melanin and is brownish in colour. The other basic form is called
Pheomelanin, which produces reddish-brown colour that is often
associated with freckles and red hair.

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The difference in the production of melanin is affected by:
Exposure to UV radiation: Melanin is produced as a response to UV radiation in
order to prevent damage to the DNA. Individuals, who are exposed to UV light,
will produce more melanin for protection.
Genetic makeup: Different ethnicities and cultures are genetically pre-disposed
to producing particular shades and amounts of melanin due to inheritance. This
is, essentially, one of the primary indicators used in determining race in the
human population.
Size of melanocytes: Melanocyte size varies in different individuals and may
lead to a difference in the amount of melanin produced per cell.
Disease conditions: Several diseases may affect melanin production, including
albinism, a genetic inability to produce melanin, and vitiligo, a progressive loss of
melanocytes.

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Melanin
synthesis
pathway

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Mechanism of Depigmentation
The various active ingredients generally used to bring about skin
lightening adopt the following pathways to reduce Melanin production:
 Selective destruction of melanocytes.
 Inhibiting/Interfering with the biosynthesis of Melanin- By changing the
melanin present in the melanosome from dark coloured, oxidized form
to a light colour, reduced form by using a reducing agent bringing
about discoloration.
 Inhibit the formation of melanosome or deform their structure
 Inhibit the biosynthesis of tyrosinase.
 Interfere with the transfer of melanosome.
 Activate desquamation to remove the uppermost layer of melanocytes
of skin containing keratinocytes bringing about exfoliation.

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Hydroquinone
• It is considered as one of the best inhibitor of the melanogenesis, by
decreasing the tyrosinase activity by 90% and hence is used in the
treatment of melanosis and other hyper pigmentary disorders. This phenolic
compound causes reversible inhibition of cellular metabolism by affecting
both DNA and RNA synthesis.
• It is also a very good depigmenter when used at concentration levels of less
that 2%. Hence products containing higher HQ concentrations than 2% is
considered as a pharmaceutical product and is strictly to be used when
prescribed by a medicinal practitioner. HQ concentration above 5% is not
advisable because of the side effects like skin irritation problems and
sometimes may even cause permanent depigmentation with long term
treatment.

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• HQ solution turns brown on exposure to air , hence use of
stabilizer like sodium meta-bisulphite or sodium sulphite become
compulsory with addition of little ascorbic acid.
• High concentration not used due to various side effects
Hydroquinone is highly reactive and potent melanocyte cytotoxic
and mutagenic compound, therefore not authorized in cosmetics
anymore.

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Mono benzyl ether Hydroquinone(MBEH)
MBEH causes depigmentation by eclectic melanocytic
destruction through free radical formation and competitive
inhibition of tyrosinase enzyme system. However unlike its
parent compound HQ, MBEH almost causes irreversible
pigmentation of skin and hence should be used only in treatment
of severe vitiligo.

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Arbutin (hydroquinone-O-beta-D-glucopyranoside)
It is one of the naturally occurring glucopyranoside found in
cranberry and blueberry leaves. It causes decreased tyrosinase
activity and is known to inhibit melanosome maturation. It is
nontoxic to melanocytes and is used in variety of pigments in
concentration less than 3%.

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Kojic acid (5-hydoxy-4-pyran-4-one-2-methyl)
Kojic acid, is another popular antibiotic skin whitening substance
produced in an aerobic process by a variety of micro-organisms, usually
derived from species such as aspergillus and penicillium, is a well-known
skin lightening agent which inhibits tyrosinase activity thereby reducing
melanin production. Copper ions are an essential metal of the active
tyrosinase site of melanin synthesis. It functions by chelating Copper at
the active site of tyrosinase enzyme. It also acts as a free radical
scavenger However, it is reported to have high sensitizing potential but is
useful to patients who cannot tolerate HQ, and can be combined with
topical corticoid to reduce skin irritation.

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Ascorbic acid and its derivatives
Vitamin C in the ascorbyl form has
been studied by various reporters and
is reported to inhibit the production of
melanin.
Glycolic acid
Glycolic acid is an alpha-hydroxy acid derived from
sugar cane (Saccharum) and it may have two skin
lightening effects. At low concentrations, it results
in a rapid desquamation of pigmented
keratinocytes. At higher concentrations, glycolic
acid results in epidermolysis. At concentrations of
3%–7%, they can increase the penetration of other
topical skin lighteners such as hydroquinone.

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Tretinoin (retinoic acid/ Vitamin A)
Tretanoin by itself acts as a weak depigmenting agent and is
known to show synergistic effect by increasing the depigmenting
of hydroquionone and its derivative.
Niacinamide ( form of vitamin B3)
Biological active form of vitamin B3 and inhibits melanosome
transfer.
Linolenic and Alpha lipoic acid
Studies have shown that they can decrease UV induced
pigmentation.
Mercury
It is one of the earliest used skin bleach products, however due
to its toxicity it is banned in many countries.

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Mushroom
Matsutake (Trichloma matsutuke) mushroom, the Korean Pine
mushroom, is popularly known as Song-Yi mushroom is traditionally used
as a decoction, dipped overnight in water and used as a facial wash to
remove summer sun tanned facial spots and for lightening of facial
wrinkles. Song-Yi mushroom liquid concentrate is said to possess better
whitening power that Kojic acid and is non-irritating and stable in most
skin whitening formulations. Song-Yi also provides a physical UV
blocking effect preventing melanin re-oxidation and subsequent re-
darkening of the skin that can occur in case of hydroquinone or kojic acid
usage.
Gluconic acid (HOOC–CHO-CHOH-CHOHCHOH-CH2OH)
It chelates copper thereby inhibiting oxidation reaction slowing down the
enzyme activity. Gluconic acid along with other actives effectively inhibit
melanogenesis to prevent skin discoloration and improve skin
complexion.

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Other commonly used home made ingredients include
Green tea extracts
Papaya juice
Lemon juice
Tomato
juice
Turmeric
powder

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Bamboo extract
Liquorice
Mulberry extract

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COMPONENTS % WT SPECIFIC EXAMPLES
Moisturizing ingredients 70% Stearyl, palmityl, lauryl, myristyl,
oleyl, sunflower seed oil,
cholesterol, soy sterol,
dimethicone, petroleum jelly,
mineral oils.
Emulsifier 1 - 15% Stearic acid, non-ionic and
anionic surfactants, cationic
surfactants, acrylic- based
polymers
Emollient 1 – 20% Lanolin, squalene, jojoba oil and
other oils and esters
Skin lightening active(s) 1 – 10% Kojic acid, vitamin C,
hydroquinone
UV absorbing actives 1- 35% Avobenzone

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COMPONENTS % WT SPECIFIC
EXAMPLES
Anti-oxidant actives 0 – 5% Vitamin C, botanicals,
Vitamin E
Rheology modifier 0 - 10% Acrylic based polymers,
xanthan gum
Pigments or Colorants 0 - 10% Iron oxides
Silicone compound 0 - 10% Dimethicone

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COMPONENTS % WT SPECIFIC
EXAMPLES
Water resistance agent) 0 - 2% Hydrophobic polymers
such as Soltex
OPT™ water resistance
agent
(trademark of Dow
Fatty alcohols 0 - 5% Thickener, skin feel agent
Water, preservative,
fragrance
Balance to 100%

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• ADD oil phase to water
phase with high shear
mixing
• When a smooth emulsion
has been formed transfer to
low shear mixing
• Cool with stirring and at 50-
55 degress centigrade , add
sodium bisulphite, ascorbic
acid, hydroquinone and
citric acid.
• Add perfume at about 40
degrees .

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• KLIGMAN took out a patent claiming synergistic compositions
for skin depigmentation comprising of a mixture of
Hydroquinone, retinoic acid and corticosteroid for example
dexamethasone.
• Highly effective in treating disorders of hyper pigmentation,
notably melasma, freckles and excess pigmentation following
inflammation.

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Disadvantages and Conclusion
• Skin lightening products interfere with the normal human biological
processing in deeper skin layers leading to damage of dermal
physiology and evokes unwanted effects like denaturation of cells,
contact skin dermatitis, pigment disorder which may further lead to
skin cancer and pigment cell death.
• Melanin present on the skin offers some amount of protection from UV
A and UV B radiation. However, the increased use of skin lightening
products leads to loss of cell pigments thereby increasing the risk of
skin cancer.
• Skin lightening is not permanent and the lightened areas become
darken on exposure to light. Hence the presence of sunscreen agent
in a topical skin lightening preparation is highly desirable, to get ideal
protection from sunlight. Nevertheless in all these efforts product
stability and its safety in use that is of paramount importance cannot
be ignored.

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References
• Lovely Glowing Skin Fair Forever by sitaram dixit
• Skin lightening products revisited- by L Petit and Peirard
• Survey and Mechanism of Skin Depigmenting and Lightening
Agents-Shoukat Parvez1†, Moonkyu Kang1, Hwan-Suck
Chung1, Chongwoon Cho1, Moo-Chang Hong2, Min-Kyu
Shin2 and Hyunsu Bae1.
• Harry’s cosmeticology, Pg 264
• Sagarins cosmetic science and technology, pg 233

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