SUNLIGHT THEORY

Sunlight Theory is not a single historical doctrine but a label applied here to a recent cluster of online claims about ultraviolet radiation and sunscreen. Its proponents commonly argue that pharmaceutical companies, dermatologists, and public-health agencies exaggerate the danger of sunlight in order to sell sunscreen and other products. More extreme versions claim that sunscreen causes cancer, blocks essential spiritual or biological energy, or is more harmful than unprotected ultraviolet exposure.

The claims draw on several genuine facts. Sunlight helps the body produce vitamin D, and exposure to daylight influences sleep and circadian rhythms. Sunscreen products differ in formulation, and questions about regulation, allergy, environmental effects, and correct use can be legitimate subjects of research. Those facts do not show that ultraviolet radiation is harmless or that the skin-cancer evidence is a pharmaceutical fabrication.

Ultraviolet radiation can damage cellular DNA and is a recognized cause of skin cancer, including melanoma and nonmelanoma cancers. Public-health and dermatological evidence distinguishes ordinary daylight exposure from excessive or unprotected exposure; it does not support the proposition that deliberately avoiding sun protection is a general treatment for cancer, autoimmune disease, or vitamin deficiency. The claim that sunscreen itself is a universal cause of cancer has not been established by reliable evidence.

The theory spreads through social-media wellness communities that combine distrust of regulators with appeals to natural living. It also overlaps with anti-pharmaceutical and medical-suppression narratives, in which any warning about a natural substance is interpreted as evidence of commercial censorship. The existence of commercial incentives in health markets does not reverse the evidence concerning ultraviolet damage.

The label is used in this encyclopedia to document the conspiracy cluster, not to recommend a health practice. Its central claims about sunscreen and cancer are contradicted by established medical evidence.