“Without glutathione, other important antioxidants, such as vitamins C and E, are not effective enough to protect the body from disease.”
Breakthrough In Cell-Defense – by Dr Allan Somersall, Ph.D., M.D. with Dr. Gustavo Bounous, M.D. FRCS(C)
Glutathione is the main ingredient in “whitening pills” and “whitening needles” commonly available on the market.
Whether it is skin care products, or whitening needles, whitening pills, health food, you can see its figure.
01 Glutathione properties
Glutathione is a white crystalline powder, melting point 195 ℃, soluble in water and dilute alcohol, insoluble in alcohol, ether and acetone.
Its solid form can exist stably, and its aqueous solution is easily oxidized by air into its oxidized form.
Its reduced specific rotation [α] 27 D: -21 (C=2.74%, H2O).
The CAS number for glutathione is 70-18-8.
02 Glutathione efficacy
Antioxidant effect:
Glutathione can destroy these free radicals, prevent oxidative stress, and prevent skin oxidation, so it has antioxidant and anti-aging effects.
Similarly, the lack of glutathione may lead to free radical flooding, which will accelerate aging and look much older than others.
Wherever free radicals are produced, there is an endless supply of glutathione, which is an indispensable element for the function of antioxidant, free radical scavenging, detoxification and other functions in the cell.
Whitening and freckle removal:
Glutathione can reduce tyrosinase activity, completely inhibit the production of melanin, decompose existing melanin, prevent the skin from producing color spots, and gradually remove the original color spots.
By blocking the formation of melanin to achieve the effect of melasma.
03 forms of glutathione
Glutathione comes in reductive and oxidized forms, and the oxidized form is the link of its reductive disulfide bond.
GSH can be produced by fermentation of yeast such as Saccharomyces cerevisiae.
Its chemical structure is as follows:
The ratio of reduced glutathione to oxidized glutathione in cells is an important index to test the level of cellular oxidative stress. The higher the ratio of GSSG to GSH indicates the higher degree of cellular oxidation.
In normal cells and tissues, more than 90% of GSH is reduced, and the remainder is the oxidized glutathione disulfide GSSG.
In the reduced state, GSH an important reducing group for the sulfyl group of cysteine, and it the main antioxidant group, while GSSG converted into reduced GSH under the action of reduced nicotinamide adenine dinucleotide phosphate (NADPH), so as to play the role of reducing and antioxidant:
NADPH+GSSG+H2O→2GSH+NADP+ OH.
GSH widely used due to its antioxidant scavenging of free radicals and inhibition of tyrosinase and melanin production, and oxidized glutathione GSSG more acceptable to formulation and consumers due to the conversion of the characteristic odor from sulfyl to disulfide bonds.
From the experiment of scavenging free radicals, the activity and efficacy of GSH are more prominent, and the scavenging ability of DPPH free radicals is 86 times that of GSSG at the same concentration.
At the same concentration, the scavenging ability of HO· free radical is at least twice that of GSSG.
At the same concentration, the ability to remove superoxide free radicals is at least 50 times.
It can seen that when the sulfhydryl group of the reduced GSH converted into a disulfide bond and becomes GSSG, its antioxidant property greatly reduced due to the disappearance of the strong reducing group -SH.
In terms of inhibiting tyrosinase activity, GSH at least 178 times that of GSSG, and GSSG further affects the enzymatic oxidation reaction in the process of melanin production due to its reduction and antioxidant properties, so the whitening effect also decreased.
04 Glutathione whitening freckle effect
At present, in the field of cosmetics, oxidized glutathione GSSG widely used because of its slightly lighter odor than reduced glutathione GSH.
From the structural point of view, the active group of oxidized glutathione – mercaptan SH has converted to disulfide bond, and theoretically the reducing ability should reduced.
In the process of melanin formation, GSH can reduce the oxidized dopa quinone and convert it into GSH dopa, and then produce a lighter color of fusomelanin instead of eumelanin, which has a whitening effect.
05 Oxidized glutathione GSSG
Although the in vitro experimental data of oxidized glutathione are general, there are data reporting that 2% GSSG lotion significantly reduces the melanin index of subjects, and improves skin fine lines and moisture retention to some extent.
For one thing: GSH is a compound that blocks the production of melanin.
GSSG is reduced to GSH by glutathione reductase in the body.
The presence and activity of GSH peroxidase and glutathione reductase have confirmed in human epidermis and dermis.
In addition, we preliminatively found that some GSSG in the cuticle penetrates the epidermal barrier in the skin permeability test in the cultured 3D skin model.
We hypothesize that GSSG applied to the skin converted into GSH, which acts on melanocytes in the epidermal layer, thereby exerting a whitening effect.
On the other hand, the addition of GSSG to hairless mice significantly increased the minimum amount of erythema exposed to UV.
This conclusion indicates that GSSG acts locally on inflammatory response through UV-induced oxidative stress, so we conclude that there is a relationship between the skin whitening effect of GSSG and oxidative stress.
The thiol group (-SH) structure of GSH has its powerful antioxidant effect. Glutathione can taken orally, injected and used externally to achieve whitening effect. Combined with tranexamic acid and VC, it can treat melasma.
References:
- [1] Wang Ting, Zheng Yunyun, et al. Comparative study on the application of reduced and oxidized glutathione in cosmetics
- [2]Fumiko Watanabe，Erika Hashizume，Gertrude P Chan，Ayako Kamimura，
- Skin-whitening and skin-condition-improving effects of topical oxidized glutathione: a double-blind and placebo-controlled clinical trial in healthy women，Clinical, Cosmetic and Investigational Dermatology
- [3] Xiong Chenyang, Yi Fan, Xue Yan, Zhu Wenyi, Meng Hong, Research Progress of Primary antioxidants in skin and their application in Cosmetics, Daily-Use Chemical Industry, Volume 48, Issue 10, October 2018