Heliotherapy, the therapeutic use of sunlight, has long been recognized for its healing effects across various physiological systems. With growing evidence supporting its role in conditions such as psoriasis, vitiligo, depression, rickets, and autoimmune diseases, heliotherapy is gaining renewed relevance as a natural, non-invasive treatment approach. Its mechanisms involve ultraviolet B (UVB)-induced vitamin D synthesis, immune modulation, hormonal balance, and regulation of circadian rhythms. Sunlight is especially vital for women’s health, influencing bone density, reproductive function, and mental well-being. However, modern lifestyles characterized by prolonged indoor activity, urbanization, and excessive sun avoidance have significantly reduced natural light exposure, contributing to widespread vitamin D deficiency and related health issues. This review highlights the therapeutic potential of heliotherapy, the physiological basis behind its effects in different conditions, the gender-specific benefits for women, and the adverse outcomes of sunlight deprivation in contemporary living. Encouraging safe, moderate sun exposure may offer a simple yet powerful strategy to support holistic health in today’s sedentary and light-deficient world.