Pigmentation marks, freckles and reddened skin are frequently felt as a nuisance. As only very few individuals however are endowed with an even skin tone, so called whitening products become increasingly popular.
What determine the skin colour?
Melanin is found in two different types of skin which is eumelanin (black-brown) and pheomelanin (reddish-yellow). Both together determine the skin color. In UV radiation the formation of melanin is increased. Melanosomes and melanocytes increase and the skin-tanning process will start. This process also includes hyperpigmentations i.e. age spots or freckles develop an increased pigmentation in comparison to their environment.
Which ingredients/substances may lighten pigmentation or whitening?
1) Hydrochinone or Arbutin
~inhibits the activity of tyrosinase which is an enzyme located in the melanosomes (cell organelles) and transforms the amino acid dopa (3.4-dihydroxyphenylalanine) into melanin.
~It is generally supposed that hydrochinone also contributes to the destruction of melanosomes and the de-activation of melanocytes whereas the keratinocytes are not affected. The natural substance arbutin with a glycoside linkage of hydrochinone to glucose shows similar reactions. In comparison to hydrochinone however this substance has the advantage of showing better resistance to atmospheric oxygen.
2) Kojic acid
~Just like hydrochinone, kojic acid (5-hydroxy-2-hydroxymethyl-4H-pyran-4-on) is a strong reducing agent and a tyrosinase inhibitor. Kojic acid is a very effective bleaching agent and very popular in Asia. The effects of kojic acid may be increased by adding AHA acids. Just like glycolic acid AHA acids have peeling effects thus removing melanin-containing substances from the skin surface on the one hand and stimulating cell formation in order to increase the exchange of melanin-containing cells on the other hand.
3) Polyphenols and extracts
~Vegetable extracts play a major role in skin whitening.
~Pertaining to this group are concentrates rich in polyphenols like liquorice or appropriate extract combinations which are better known by the popular term gigawhite: mallow, (malva sylvestris), peppermint (mentha piperita), primrose which is also called cowslip (primula veris), lady's mantle (alchemilla vulgaris), veronica, also called speedwell (veronica officinalis), balm (melissa officinalis) yarrow (achillea millefolium).
~Most of the components are tyrosinase inhibitors. Decisive factor here is a transport vehicle which penetrates the effective agents into the skin. In this case, liposomes and nanoparticles have proved successful.
~Whereas pure vitamin C only has topical effects similar to AHA acid, the reducing effect of vitamin C which penetrated into the skin inhibits the formation of intermediate products of the melanin synthesis. A very important prerequisite for the penetration is that the derivatives are encapsulated as for example vitamin C palmitate which generally is encapsulated in nanoparticles because of its solubility in fats. After its penetration into the skin, enzyme activity causes the molecule to break down by means of esterases into palmitic acid and free vitamin C which then is able to inhibit the formation of melanin. A further vitamin C derivative is sodium ascorbyl phosphate which is encapsulated in liposomes due to is water solubility.
Advantages of vitamin C preparations:
~the formation of components quite identical to endogenic substances as well as their low concentration. Unlike hydrochinone or arbutin only the melanin synthesis is inhibited in this case whereas the existing melanin will not be affected. The products however are highly effective and free of any side effects. A further advantage of encapsulated vitamin C derivatives as against free vitamin C is their extended shelf life.
Disadvantages of vitamin C
~vitamin C derivatives have to be used as a preventive measure for an extended period before its effects become visible.
Preventive measures:
Avoiding sun radiation as well as applying sun screen products are the most essential preventive measures accompanying skin lightening. It has to be kept in mind however, that a certain amount of UV radiation is vital for the skin in order to form vitamin D. High concentrations of UV screens though will chronically stress the skin.The fact, that pigmentation marks frequently are caused by photosensitizing substances often is ignored. This also applies for certain medication and some home remedies too like St. John's wort belong to this group. Also some fragrances like bergamot essence which is contained in a lot of perfumes show photosensitizing effects.Two further substances are important for an even skin complexion: echinacea extract and vitamin K. Both have positive effects in cases of couperosis and reddened skin, vitamin K additionally in cases of rosacea, purpura and dark rings under the eyes.
Protecting against UV radiation
By nature, the sensitivity against UV rays increases with the application of bleaching products as the natural protection of melanin is suppressed. A very interesting aspect in this case is the application of CM-glucan as a skin protecting substance.A preventive application of vitamin C liposomes in combination with gigawhite liposomes also is an alternative. The latest findings show that the linoleic acid which is chemically bound in liposomes contributes to the synergy here. Encapsulation in liposomes increases the effects and enables a low dosage which means that the products can be used on a long-term base. Adding CM-glucane (photo-protective) and vitamin K (against reddened skin) is an almost ideal combination of substances. Regarding pigmentation marks the dermatologist should be contacted in any case of doubt in order to exclude the formation of melanoma.
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