Steviol Glycosides

Compound Class	Steviol glycosides — ent-kaurene diterpene glycosides sharing a common steviol aglycone backbone
Representative Members	Rebaudioside A (Reb A), stevioside, rebaudioside M (Reb M), rebaudioside D
Botanical Sources	Stevia rebaudiana (stevia)
Plant Part(s)	Leaf
Typical Standardisation	Individual glycoside purity by HPLC (e.g. Reb A 97–99%) or total steviol glycosides; E 960 specification requires ≥95% total
Primary Applications	High-intensity zero-calorie sweetening for food, beverage, and supplement formulation
Claim Strength (Overview)	High for sweetening function and regulatory safety status (EFSA/JECFA ADI established)
Buy from Herbuno	Reb A 99% (Stevia) | Stevia Sweetener | Stevia rebaudiana → Stevioside 90% (Stevia) | Stevia Sweetener | Stevia rebaudiana →

Name origin: Steviol glycosides are named for their shared aglycone, steviol, an ent-kaurene diterpene, to which varying numbers and arrangements of glucose, rhamnose, and xylose sugars are attached — the specific sugar configuration determining each glycoside’s individual name (rebaudioside A, D, M, and so on) and, critically, its sweetness intensity and off-taste profile. The genus honours the 16th-century Spanish botanist and physician Petrus Jacobus Stevus. Traditional use: The Guaraní people of Paraguay and Brazil used Stevia rebaudiana leaf — which they called ka’a he’ê, "sweet herb" — for centuries as a sweetener for the bitter yerba mate infusion and in traditional medicine, a use documented by European naturalists in the late 19th century but which remained largely a regional curiosity until Japanese food manufacturers began commercializing stevia extracts in the 1970s as a sugar alternative. Research trajectory: Steviol glycoside research has been driven overwhelmingly by regulatory toxicology rather than efficacy investigation — the compounds’ sweetening function requires no clinical demonstration — culminating in a formal Acceptable Daily Intake established by the Joint FAO/WHO Expert Committee on Food Additives and independently by EFSA. Commercial research has instead focused on isolating and biosynthesizing the minor glycosides (particularly Reb M) that offer superior taste profiles to the abundant but bitter-finishing stevioside. Commercial source: Stevia rebaudiana leaf extract purified to individual glycoside specifications is the commercial format, with Reb A the market-dominant grade and Reb M increasingly sought for its cleaner sweetness profile.

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Evidence for Steviol Glycosides Applications

Steviol glycosides occupy an unusual position in this index: their primary evidence base is regulatory-toxicological rather than clinical-efficacy, because their function (sweetening) is self-evident and requires no trial demonstration. The European Food Safety Authority’s Panel established an Acceptable Daily Intake of 4 mg per kg body weight per day for steviol glycosides, expressed as steviol equivalents, a level consistent with that already established by the Joint FAO/WHO Expert Committee on Food Additives, based on application of a 100-fold uncertainty factor to the no-observed-adverse-effect level from a two-year rat carcinogenicity study (EFSA 2010). This is a formal regulatory safety determination, not a literature-derived claim assessment — a materially stronger form of substantiation than most compounds in this index carry. Claim strength: High (regulatory-established).

The ADI has been repeatedly re-examined and upheld. In a 2024 opinion, the EFSA Panel evaluated a proposed increase of the ADI from 4 mg/kg body weight per day to either 6 or 16 mg/kg and concluded that, based on the currently available absorption, distribution, metabolism and excretion dataset, there was insufficient justification to increase the existing ADI — a decision that reaffirms rather than expands the established safety margin, and one formulators working near exposure limits should note (EFSA 2024). EFSA has separately noted, in earlier exposure assessments, that conservative estimates suggested the ADI could be exceeded at maximum proposed use levels in both adults and children — a real formulation constraint rather than a theoretical one. Claim strength: High.

The individual steviol glycosides differ substantially in sensory performance, which is the central commercial fact about this compound class. Stevioside, the most abundant glycoside in the leaf, carries a well-documented bitter and liquorice-like aftertaste at higher use levels; rebaudioside A offers a cleaner profile and became the market-dominant grade for that reason; and rebaudioside M and D, present only in trace quantities in the natural leaf, offer a still cleaner, more sucrose-like sweetness that has driven substantial investment in enzymatic bioconversion and fermentation routes to produce them at commercial scale. Claim strength: Moderate (sensory/formulation).

Steviol glycosides are not absorbed intact: they pass to the colon where gut microbiota hydrolyse them to the common aglycone steviol, which is then absorbed, metabolized in the liver to steviol glucuronide, and excreted in urine. This shared metabolic endpoint is precisely why the ADI is expressed as steviol equivalents rather than per individual glycoside — all steviol glycosides converge on the same absorbed compound, and a formulator’s exposure calculation must account for this by converting glycoside mass to steviol-equivalent mass. Claim strength: High (established metabolism).

Production route has become a live regulatory and labelling issue: EFSA and JECFA have now assessed steviol glycosides produced not only by leaf extraction but also by enzymatic bioconversion of purified leaf extracts and by fermentation using genetically modified yeast strains such as Yarrowia lipolytica, extending the existing ADI to these routes while maintaining separate specifications. Formulators making "natural" or "plant-derived" positioning claims should confirm the actual production route of their material, as fermentation-derived Reb M is chemically identical but provenance-distinct from leaf-extracted material. Claim strength: High (regulatory).

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Dosage & Formulator Specification

Herbuno carries purified Reb A at 99% and 97%, stevioside at 90%, stevia leaf extract at 95%, an ultra-concentrated pure leaf extract, whole organic stevia leaf powder, and a water-soluble liquid extract — a range spanning high-purity single-glycoside grades for precision beverage and supplement formulation through to whole-leaf material for clean-label and traditional-positioning applications.

Use-level calculation for this ingredient is governed by the ADI rather than by an efficacy dose: at 4 mg/kg body weight per day expressed as steviol equivalents, a 70 kg adult’s ADI corresponds to 280 mg/day of steviol equivalents. Because steviol glycosides differ in molecular weight, formulators must convert glycoside mass to steviol-equivalent mass rather than using glycoside weight directly — and should note EFSA's finding that conservative exposure estimates suggest the ADI could be exceeded at maximum proposed use levels, particularly in children, making cumulative-exposure modelling across a product portfolio a genuine due-diligence requirement rather than a formality.

Analytical verification should specify individual glycoside content by HPLC against the relevant reference standards, since the E 960 specification requires not less than 95% total steviol glycosides and since individual glycoside identity (not merely total content) determines sensory performance. Where a product carries "natural" or leaf-derived positioning, documentation of production route — leaf extraction versus enzymatic bioconversion versus fermentation — should be obtained, as all three routes now have regulatory approval but differ materially in provenance.

Steviol glycosides have an established regulatory safety status with a formal ADI, and the EFSA Panel has repeatedly found no safety concern at approved use levels, including for the newer bioconversion- and fermentation-derived preparations. The principal practical constraint is not toxicity but exposure ceiling: because the ADI can plausibly be exceeded at maximum use levels across a diet high in stevia-sweetened products, portfolio-level exposure modelling is advisable. Sensory limitation, particularly stevioside’s bitter and liquorice-like finish at higher concentrations, is typically the binding practical constraint on use level well before the ADI is approached in a single product.

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Frequently Asked Questions — Steviol Glycosides

What is the acceptable daily intake for steviol glycosides?
EFSA and JECFA have both established an ADI of 4 mg per kg body weight per day, expressed as steviol equivalents — roughly 280 mg/day of steviol equivalents for a 70 kg adult. EFSA reviewed a proposal to raise this in 2024 and concluded there was insufficient justification to increase it.

Why is the ADI expressed as "steviol equivalents" rather than per glycoside?
Because all steviol glycosides converge on the same absorbed compound. They are not absorbed intact — gut bacteria hydrolyse them in the colon to the shared aglycone steviol, which is then absorbed and metabolized. Formulators must therefore convert glycoside mass to steviol-equivalent mass when calculating exposure.

What is the difference between Reb A, stevioside, and Reb M?
They differ in sugar configuration and therefore in taste. Stevioside is the most abundant leaf glycoside but has a bitter, liquorice-like aftertaste. Reb A offers a cleaner profile and became the market standard. Reb M and Reb D, present only in trace amounts naturally, have the most sucrose-like sweetness, driving investment in enzymatic and fermentation production routes.

Are fermentation-derived steviol glycosides still "natural"?
This is a labelling and provenance question rather than a safety one. EFSA and JECFA have approved steviol glycosides produced by leaf extraction, enzymatic bioconversion, and fermentation using genetically modified yeast. The products are chemically identical but differ in provenance, so any "natural" or "plant-derived" claim should be verified against the actual production route.

Related compounds: Stevioside, Rebaudioside A, Erythritol, Glycyrrhizin

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Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.

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