Is IgG useful for skin aging?

IgG testing (especially IgG4) for skin aging lacks scientific validation. While IgG antibodies are part of immune responses and chronic inflammation, no robust clinical evidence directly links specific IgG levels to skin aging processes like wrinkle formation, loss of elasticity, or collagen degradation. Most commercial IgG tests are marketed for food sensitivities, where evidence is already controversial. For skin aging, well-established factors include UV exposure, oxidative stress, glycation, hormonal changes, and lifestyle (diet, sleep, smoking). An IgG test provides no actionable information for skin health and may lead to unnecessary dietary restrictions. Instead, evidence-based approaches such as skin aging scores (e.g., based on methylation patterns) or dermatological assessments are recommended. Conclusion: IgG testing for skin aging is marketing, not medicine.