Stevia sweeteners are made from the leaves of Stevia rebaudiana, a small plant in the daisy family native to Brazil and Paraguay. The leaves contain naturally occurring sweet compounds called steviol glycosides, which are 200 to 300 times sweeter than table sugar by weight. These compounds are extracted from dried leaves using water, then purified and concentrated into the powders, liquids, and granules you find on store shelves.
The Plant Behind the Sweetener
Stevia rebaudiana is a tender perennial that thrives in warm, humid tropical climates. It grows natively in southwestern Brazil and Paraguay, where indigenous Guaraní people used the leaves to sweeten drinks and medicines long before commercial production began. The plant goes by several common names: candy leaf, sugar leaf, sweet leaf, and sweet herb of Paraguay.
The plant looks nothing like sugarcane or sugar beets. It’s a bushy herb with small white flowers, more closely related to sunflowers and chrysanthemums than to any traditional sugar crop. Today, stevia is commercially farmed in countries across South America, Asia, and parts of Africa, with China being one of the largest producers.
What Makes the Leaves Sweet
The sweetness in stevia leaves comes from a group of compounds called steviol glycosides. The two most abundant are stevioside, which makes up roughly 9.1% of the leaf’s dry weight, and rebaudioside A (often labeled “Reb A”), at about 3.8%. Several other minor glycosides are present in smaller amounts, but these two do the heavy lifting in commercial sweeteners.
Stevioside has a noticeable bitter or licorice-like aftertaste, which is why many stevia products are formulated to contain higher proportions of rebaudioside A. Reb A delivers a cleaner, more sugar-like sweetness. When you see “stevia” on a food label, the product typically contains one or more of these purified glycosides rather than ground-up whole leaf.
How Stevia Extract Is Produced
Turning stevia leaves into the white powder or clear liquid in your pantry involves a few key steps. The process starts with harvesting and drying the leaves, then grinding or crushing them to break down the plant material. This grinding step has a major influence on how efficiently the sweet compounds can be pulled out.
Next, the crushed leaves are steeped in hot water, much like brewing a strong tea. Water is the primary solvent used to dissolve the steviol glycosides out of the leaf material. Some industrial methods use alcohol-based solvents or apply ultrasound or microwave energy to speed things up, but a simple hot-water extraction works well and aligns with greener production practices.
After steeping, the liquid is separated from the spent leaves through filtration. What remains is a dark, sweet extract that still contains plant pigments, minerals, and other non-sweet compounds. This crude extract goes through purification, often using specialized resins or membrane filtration, to isolate the steviol glycosides and remove everything else. The final product is a highly purified sweetener, typically at least 95% pure steviol glycosides.
How Your Body Processes It
Steviol glycosides pass through your stomach and small intestine largely intact because human digestive enzymes don’t break them down. Once they reach the colon, gut bacteria strip away the sugar molecules attached to each glycoside, releasing a compound called steviol. Steviol is then absorbed into the bloodstream, converted by the liver into a form called steviol glucuronide, and excreted primarily through urine.
This metabolic pathway is the same in both adults and children, and it holds true regardless of which specific steviol glycoside you consume or how the product was manufactured. Because the sweet compounds aren’t broken down into glucose or fructose at any point, stevia does not raise blood sugar levels, which is a major reason it appeals to people managing diabetes or watching their calorie intake.
Whole Leaf vs. Purified Extract
There’s an important regulatory distinction between the stevia products sold as sweeteners and the raw plant itself. The FDA has issued “no questions” letters for purified steviol glycosides at 95% purity or above, recognizing them as Generally Recognized as Safe (GRAS) for use in food and beverages. This means manufacturers can add them to conventional products without special premarket approval.
Whole stevia leaves and crude (unrefined) stevia extracts do not carry that same GRAS designation. You can buy whole dried stevia leaves as a dietary supplement or grow the plant in your garden, but food manufacturers in the U.S. cannot use unrefined leaf or crude extracts as sweetening ingredients in packaged foods. The purification process is what gives commercial stevia its regulatory green light, because it removes compounds that haven’t been evaluated to the same degree.
What Ends Up in the Final Product
The stevia you buy at the grocery store rarely contains only steviol glycosides. Packets and baking blends are often bulked up with other ingredients to make them easier to measure and use like sugar. Common fillers include erythritol (a sugar alcohol), dextrose, or inulin (a plant fiber). These bulking agents add volume without significant calories, since a tiny amount of pure stevia extract would be impractical to scoop or sprinkle.
Liquid stevia drops tend to be more straightforward, usually containing purified steviol glycosides in a water or alcohol base. If you want the least processed option available commercially, liquid drops with minimal added ingredients are the closest you’ll get to pure extract. Checking the ingredient list will tell you quickly whether your stevia product is mostly glycosides or mostly filler.