Carotenoids are pigments of great importance for human health due to their antioxidant properties and protection against age-related eye diseases. Assessing skin carotenoid levels serves as a biomarker for fruit and vegetable intake and significantly correlates with serum and macular carotenoids. Two non-invasive techniques, reflection spectroscopy (RS) and resonance Raman spectroscopy (RRS), are prominently used in clinical and nutritional research to measure skin carotenoid levels. RS enhances reflectance spectroscopy through pressure application to reduce chromophore interference, while RRS uses molecular vibrational analysis for specific measurements. Both methods offer quick, reliable, and noninvasive assessment of skin carotenoids, making them vital for dietary assessment, public health studies, and personalized nutrition interventions.