Steviol glycosides are a group of plant-derived sweeteners extracted from the leaves of Stevia rebaudiana. They are roughly 200-300 times sweeter than sucrose, so the amount used in a formula is very small and the calories contributed are negligible. Their Codex classification number is INS 960.
They are not a single compound. Chemically they are diterpene glycosides: the aglycone is steviol, and the sugar portion carries different numbers and types of glucose units. The best-known components are stevioside, rebaudioside A (Reb A), rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside M, rebaudioside E, rebaudioside F, dulcoside A and steviolbioside.
Each component differs in sweetness, bitterness and water solubility. That is why commercial products are named after a component (Reb A 97%, Reb M) or after a combination (total glycosides 95% with Reb A 60%, abbreviated ST95-RA60) rather than being sold simply as “steviol glycosides”. It is also the root cause of the wide spread in price and taste between one steviol glycoside product and another.
In industry, steviol glycosides are separated and purified from dried leaves by physical processes - water extraction, resin adsorption and recrystallisation - and high-purity products reach 95%-98%. The main regulatory systems have all approved them as food sweeteners: China lists them in GB 2760, the United States uses them as GRAS, the European Union assigns E 960, and internationally JECFA sets the specifications. The current JECFA specification is already divided by production method into leaf extraction, fermentation, enzymatic conversion and glycosylation (INS 960a-960d).
Because they deliver high-intensity sweetness with almost no added calories, steviol glycosides are among the most widely used high-intensity sweeteners in sugar-reduction today.
Primary sources: GB 2760-2024 (China National Center for Food Safety Risk Assessment, gb2760.cfsa.net.cn) | E 960 (EUR-Lex) | JECFA specifications (FAO, INS 960a-960d)
Related products: Reb-A Series · Optimvia Reb-M / Reb-D · GSG Series