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Sweeteners · Stevia Rebaudiana Leaf Extract · CAS 91722-23-5

Stevia Extract

Stevia extract is 200–400× sweeter than sugar, is not fermented by S.mutans, and inhibits α-glucosidase — the enzyme S.mutans needs to build cariogenic biofilm.

QDRO position

We use it

Safe non-cariogenic sweetener; stevioside inhibits S.mutans α-glucosidase — an added anti-caries bonus.

Effective concentration

0.1–0.3% (as glycosides)

Typical on market: 0.1–0.5%

Stevia Extract

What it is

Stevia extract is derived from the leaves of Stevia rebaudiana Bertoni — a perennial plant of the Asteraceae family, native to South America. The principal sweet components are diterpene glycosides: stevioside and rebaudioside A (Reb A). Reb A delivers a cleaner, less bitter taste profile and is preferred for oral-care applications. Its sweetness is 200–400 times greater than sucrose, yet it provides no calories and is not fermented by cariogenic bacteria.

How it works

Stevia functions as a sweetener in two simultaneous modes:

  1. Masking bitterness of actives — many functional ingredients (fluoride, zinc, cetylpyridinium chloride) have unpleasant taste. Reb A masks them without introducing fermentable sugars.

  2. Inhibition of S. mutans α-glucosidase — stevioside competitively inhibits α-glucosidase, the enzyme streptococci use to synthesise glucan and build biofilm on enamel surfaces. This reduces bacterial adhesion and the cariogenicity of plaque.

Unlike sucrose, xylitol, erythritol, and stevia are not metabolised by S. mutans to acid — plaque pH does not drop below the critical threshold of 5.5.

Efficacy

Large-scale clinical RCTs on stevia specifically in toothpaste are limited; however, in vitro data and short-term clinical studies show:

  • Stevioside reduces glucosyltransferase activity in S. mutans, decreasing biofilm accumulation.
  • Reb A is stable across a broad pH range (3–9) and at temperatures up to 200°C — technologically straightforward for paste manufacturing.
  • Stevia solutions produce no cariogenic response in Stephan curve tests (plaque pH does not fall after rinsing with stevia solution).

Safety

EFSA and the FDA have placed stevia glycosides on the GRAS (Generally Recognized As Safe) list. Genotoxicity has not been confirmed (Brusick, 2008). There are no restrictions on use in cosmetics including oral care. The ADI is 4 mg/kg body weight expressed as steviol — a level not approached even with accidental toothpaste ingestion.

Role in the QDRO formula

In QDRO formulas, stevia (Reb A) serves as the primary or supplementary sweetener to mask the bitterness of v.pro actives without compromising caries safety. For ingredient-conscious consumers, this is a clear claim: sweet, clean, sugar-free, no sorbitol, with an additional antibacterial mechanism.