Mammals store and use elemental sulfur as S8, the ring-shaped octasulfur form that is the bright-yellow form of the element seen in nature. It was already known that prokaryotes handle sulfur in this form, but no one had seen it in higher animals until now. Researchers detected the S8 signature using Raman spectroscopy and a mass spec method that captures the molecule in a host-guest form inside a polyaromatic capsule structure. That technique shows that the molecule is found in human mitochondria and in cellular lipid droplets, with levels reaching 100mM or more in cancerous tissue. A normal human carries around 10s of grams of elemental sulfur in their cells, synthesized as an independent product of endothelial nitric oxide synthase (eNOS), where its hydrophobic nature prevents lipid peroxidation as an antioxidant backstop to glutathione.