Melanin is a nonpolar heteropolymer responsible for skin and hair pigmentation, as well as providing protection against UV radiation. It exists in three primary types: eumelanin, pheomelanin, and neuromelanin. Eumelanin, which appears black or brown, is found in skin, hair, and various organisms like birds and squid. It is synthesized from tyrosine via the enzyme tyrosinase and serves as a defense against UV radiation by scavenging free radicals. Pheomelanin, which ranges from yellow to red due to the sulfur it contains from L-cysteine, contributes to lighter skin tones and red hair. Unlike eumelanin, pheomelanin can be more phototoxic, increasing oxidative stress when exposed to UV light. Neuromelanin, located in the brain’s substantia nigra, resembles eumelanin but has distinct neurological roles tied to dopamine metabolism. The complex structure of melanin enables it to act as both an antioxidant and a pro-oxidant. It has significant free radical scavenging and photoconductive properties, and it can bind metal ions, helping with metal storage and detoxification. These diverse properties highlight melanin’s vital role in biology and its potential applications in biomedicine and materials science.