GLUTATHIONE FOR SKIN LIGHTENING / UVA CLINICAL PUBLIC AWARENESS 1 Controversies and Challenges in the Use of Glutathione for Skin Tone Lightening Indunil Karunarathna 1 , Sau Bandara 1 , Asoka Jayawardana 1 , Kapila De Alvis 1 , P Gunasena 1 , T Hapuarachchi 1 , U Ekanayake 1 , S Rajapaksha 1 , K Gunawardana 1 , P Aluthge 1 , S Gunathilake 1 1. Ministry of Health / Teaching Hospital Badulla / University of Colombo. Abstract: The use of glutathione as a skin lightening agent has gained significant popularity, particularly among ethnic populations with darker skin tones. This trend is driven by aggressive marketing and the demand for systemic depigmenting treatments. While glutathione is recognized for its potent antioxidant properties, its role in skin lightening remains controversial due to limited and inconclusive clinical evidence. Despite its approval for specific medical conditions such as severe liver disorders and chemotherapy-induced neurotoxicity, glutathione is frequently used off-label for skin whitening, often without adequate regulation. This review examines the current status of glutathione in skin lightening, focusing on its purported antimelanogenic mechanisms, safety profile, and clinical efficacy. We explore various administration routes, including intravenous, oral, and topical applications, and assess the quality of available studies. The review highlights the gaps in knowledge regarding optimal dosage, duration of treatment, and long-term effects, urging the need for more rigorous research to establish clear guidelines for its use. Keywords: Glutathione, skin lightening, hyperpigmentation, antioxidant, antimelanogenic, intravenous glutathione, oral glutathione, topical glutathione, skin of color, cosmetic dermatology, safety, efficacy, clinical evidence, regulatory approval. Key points: Evidence and Efficacy: Oral Glutathione: Limited studies show variable results, with some evidence suggesting reduced melanin indices but with issues like small sample sizes and short study durations. Topical Glutathione: Some evidence supports temporary skin whitening, though results are inconsistent and studies are limited. Intravenous Glutathione: Controversial and largely unsupported by robust clinical evidence. Adverse effects and high costs raise significant concerns. Mechanisms of Action: Inhibition of Tyrosinase: Glutathione may inhibit the enzyme tyrosinase, crucial in melanin production. Shift in Melanogenesis: Potential to shift melanogenesis from darker eumelanin to lighter pheomelanin. Antioxidant Effects: Scavenging of free radicals might contribute to its skin-lightening effects. Formulations and Administration: Oral Supplements: Generally have low bioavailability; effectiveness in systemic skin lightening is debated. Topical Products: Limited evidence suggests possible efficacy in temporary skin lightening. Intravenous Injections: High doses and frequent administration recommended by some manufacturers, but with questionable safety and efficacy. Adverse Effects: Topical and Oral: Generally well-tolerated with few adverse effects reported. Intravenous: Serious concerns include liver dysfunction, allergic reactions, and other severe complications. Reports of adverse effects have been documented, including potentially fatal conditions. Regulatory Status: Approval: Glutathione is approved for specific medical uses (e.g., liver disorders, neurotoxicity) but not specifically for skin lightening in many regions. Regulations: Usage for skin lightening is often not regulated, leading to widespread, unregulated use. Research and Controversies: Study Limitations: Many studies have small sample sizes, short durations, and methodological flaws. Controversial Aspects: The efficacy of IV glutathione remains unproven, and marketing claims are not always supported by scientific evidence. Future Directions: Need for High-Quality Trials: More rigorous, large-scale, and long-term studies are needed to establish the safety and efficacy of glutathione for skin lightening. Exploration of Derivatives: Esterified forms of glutathione, such as GSH-MEE, show promise in preliminary studies and may offer more effective and safer alternatives. Introduction The pursuit of a lighter skin tone or fairer complexion has long been prevalent among people with skin of color (SOC). This trend has led to the widespread use of topical agents originally developed to treat hyperpigmentation, such as skin lightening therapies. These topicals often contain hydroquinone, alpha and beta hydroxy acids, tretinoin, mequinol, arbutin, vitamin C, soy extracts, and other ingredients, including newer cosmeceuticals. They are commonly used to treat facial melanoses, such as melasma, and for general skin lightening, particularly of the face, neck, and other exposed areas. However, these topical treatments have limitations, including local adverse effects and the substantial amounts required for application over large surface areas. Additionally, their effects are generally confined to the application site, without any notable systemic skin lightening