Wearable optical sensors for sweat monitoring have emerged as a promising technology for non-invasive physiological monitoring. These sensors utilize optical methods such as colorimetry, surface-enhanced Raman spectroscopy (SERS), fluorescence, and electrochemiluminescence (ECL) to detect sweat components, including electrolytes, metabolites, hormones, and nutrients. The integration of flexible electronics, microfluidics, and advanced materials has enabled the development of compact, portable, and skin-interfaced sensors that can provide real-time data on sweat composition. Colorimetric sensors use chromogenic molecules that change color in response to sweat components, while SERS sensors leverage plasmonic nanostructures to enhance signal detection. Fluorescence sensors detect changes in fluorescence intensity, and ECL sensors generate light through electrochemical reactions. These technologies offer advantages such as high sensitivity, label-free detection, and the ability to monitor multiple biomarkers simultaneously. However, challenges remain in terms of long-term stability, environmental impact, and the need for specialized equipment for data analysis. Future developments aim to improve sensor comfort, reduce costs, and integrate artificial intelligence for enhanced data interpretation. The review highlights recent advancements in materials, sensor design, and data analysis, emphasizing the potential of optical sweat sensors in personalized healthcare, sports, and disease diagnosis.Wearable optical sensors for sweat monitoring have emerged as a promising technology for non-invasive physiological monitoring. These sensors utilize optical methods such as colorimetry, surface-enhanced Raman spectroscopy (SERS), fluorescence, and electrochemiluminescence (ECL) to detect sweat components, including electrolytes, metabolites, hormones, and nutrients. The integration of flexible electronics, microfluidics, and advanced materials has enabled the development of compact, portable, and skin-interfaced sensors that can provide real-time data on sweat composition. Colorimetric sensors use chromogenic molecules that change color in response to sweat components, while SERS sensors leverage plasmonic nanostructures to enhance signal detection. Fluorescence sensors detect changes in fluorescence intensity, and ECL sensors generate light through electrochemical reactions. These technologies offer advantages such as high sensitivity, label-free detection, and the ability to monitor multiple biomarkers simultaneously. However, challenges remain in terms of long-term stability, environmental impact, and the need for specialized equipment for data analysis. Future developments aim to improve sensor comfort, reduce costs, and integrate artificial intelligence for enhanced data interpretation. The review highlights recent advancements in materials, sensor design, and data analysis, emphasizing the potential of optical sweat sensors in personalized healthcare, sports, and disease diagnosis.