Raw kojic acid is available, but it is not recommended for skin use. Kojic acid should be diluted to concentrations of no more than 4 percent. A concentration of 1 to 2 percent is recommended to reduce the chance of skin irritation. Jara, J.R.; Aroca, P.; Solano, F.; Martinez, J.H.; Lozano, J.A. The role of sulfhydryl compounds in mammalian melanogenesis: The effect of cysteine and glutathione upon tyrosinase and the intermediates of the pathway. Biochim. Biophys. Acta 1988, 967, 296–303. [ Google Scholar] [ CrossRef] Benedetto, J.P.; Ortonne, J.P.; Voulot, C.; Khatchadourian, C.; Prota, G.; Thivolet, J. Role of Thiol Compounds in Mammalian Melanin Pigmentation.1. Reduced and Oxidized Glutathione. J. Investig. Dermatol. 1981, 77, 402–405. [ Google Scholar] [ CrossRef][ Green Version]

Subjects applied test lotion to one side of the face and a placebo lotion to the other side twice daily for 10 weeks.

A number of human and animal studies have found that eating sulfur-rich vegetables may reduce oxidative stress by increasing glutathione levels ( 3, 4, 5).

I usually use an exfoliating sponge when washing my face, which may account for the results I get. However, one thing to note is that the soap does burn a little bit if you leave it on for more than 30 seconds. It also can be a little irritating to sensitive skin at times, so you may want to test it out on a small patch of skin before using it all over your body. Thiol compounds such as cysteine and glutathione rapidly react with DQ produced in the TYR-catalyzed reaction [ 82]. If cysteine is the reactant, 5- S-cysteinyl dopa (5- S-CD) or 2- S-cysteinyl dopa (2- S-CD) are produced [ 83]. 5- S-CD and 2- S-CD are then oxidized to their quinones in concert with the reduction of DQ to DOPA or in a TYR-catalyzed reaction [ 84] and then cyclized to benzothiazine or benzothiazole intermediates [ 30, 85]. The polymerization reaction between these intermediates leads to the production of the final product, pheomelanin [ 4, 30, 31]. Halprin, K.M.; Ohkawara, A. Glutathione and Human Pigmentation. Arch. Dermatol. 1966, 94, 355. [ Google Scholar] [ CrossRef] [ PubMed]

In one study, adults took 500–1,000 mg of vitamin C daily for 13 weeks, leading to an 18% increase of glutathione in white blood cells ( 8). Tse, T.W. Hydroquinone for skin lightening: Safety profile, duration of use and when should we stop? J. Dermatol. Treat. 2010, 21, 272–275. [ Google Scholar] [ CrossRef]

Sugumaran, M. Molecular Mechanisms for Mammalian Melanogenesis—Comparison with Insect Cuticular Sclerotization. FEBS Lett. 1991, 295, 233–239. [ Google Scholar] [ CrossRef][ Green Version] Adelmann, C.H.; Traunbauer, A.K.; Chen, B.; Condon, K.J.; Chan, S.H.; Kunchok, T.; Lewis, C.A.; Sabatini, D.M. MFSD12 mediates the import of cysteine into melanosomes and lysosomes. Nature 2020, 588, 699–704. [ Google Scholar] [ CrossRef] Lo, M.; Wang, Y.Z.; Gout, P.W. The x(c)(-) cystine/glutamate antiporter: A potential target for therapy of cancer and other diseases. J. Cell. Physiol. 2008, 215, 593–602. [ Google Scholar] [ CrossRef] [ PubMed]

Funding

The small airways of the lungs require glutathione to function properly. In fact, healthy lungs have up to 1,000 times more glutathione than other parts of the body ( 36). These brands have all been around for years and are well respected by their customers and the beauty community in general (particularly in Asia). And while I haven’t personally tried them all yet, I’ve heard great things about each of them. Cooksey, C.J.; Garratt, P.J.; Land, E.J.; Pavel, S.; Ramsden, C.A.; Riley, P.A.; Smit, N.P. Evidence of the indirect formation of the catecholic intermediate substrate responsible for the autoactivation kinetics of tyrosinase. J. Biol. Chem. 1997, 272, 26226–26235. [ Google Scholar] [ CrossRef][ Green Version] This vitamin has many functions, including working as an antioxidant to protect cells from oxidative damage. It also maintains the body’s supply of other antioxidants, including glutathione.

Chung, B.Y.; Choi, S.R.; Moon, I.J.; Park, C.W.; Kim, Y.H.; Chang, S.E. The Glutathione Derivative, GSH Monoethyl Ester, May Effectively Whiten Skin but GSH Does Not. Int. J. Mol. Sci. 2016, 17, 629. [ Google Scholar] [ CrossRef] [ PubMed][ Green Version] Weschawalit, S.; Thongthip, S.; Phutrakool, P.; Asawanonda, P. Glutathione and its antiaging and antimelanogenic effects. Clin. Cosmet. Investig. Dermatol. 2017, 10, 147–153. [ Google Scholar] [ CrossRef] [ PubMed][ Green Version] Glutathione + Kojic acid does not lead to any prominent side effects and is generally safe to use. However, if you experience any undesirable effects like irritation and inflammation while using this product, report to your healthcare provider immediately.

Is Kojic Acid Better Than Glutathione?

Anti-aging effect: Products containing kojic acid may lighten the skin, which can improve the appearance of age spots and sun damage. The reduction of dark spots can have an anti-aging effect. Han, J.Y.; Park, S.O.; Hahm, J.H.; Kook, H.I. Clinical Effect of Glutathione (Tathione) on Melasma. Korean J. Dermatol. 1977, 15, 57. [ Google Scholar]