What Do Licorice Root, Papaya, and Black Cherry Do in Toothpaste?
Licorice root contains compounds — licoricidin, glabridin, glycyrrhizol A — that interfere with S. mutans, the bacterium most associated with cavities. The interesting result is clinical. A 2021 randomized double-blind trial put 52 adults aged 18 to 55 on either a licorice extract mouthwash at 16 mg/mL or chlorhexidine, the standard antiseptic rinse, for one week. Salivary S. mutans counts fell from about 258 to 78 in the licorice group. Chlorhexidine fell from 281 to 86.
A botanical matching the reference antiseptic is a genuinely notable finding, and it's why licorice belongs in the conversation at all.
Do papaya and black cherry have the same evidence behind them?
Papaya has one relevant clinical trial: 100 adults aged 18 to 26, four weeks, papaya leaf extract dentifrice versus an SLS-free control. Interdental bleeding sites dropped 54% to 75% across every group — including the controls — and the papaya groups were not significantly better than the comparison paste. Plaque scores showed no differences at all. Note also that the trial used leaf extract; toothpaste papaya is fruit-derived.
Black cherry is thinner still. Berry polyphenols as a class do inhibit S. mutans biofilm — a 2021 study in Antibiotics found a blueberry, cranberry and strawberry fraction cut biofilm 50% at 62 µg/mL and 90% at 500 µg/mL, and suppressed the luxS quorum-sensing gene by roughly half. Black cherry was not in that fraction, and we found no trial testing it in the mouth.
So why are they in the formula?
Because a paste has to taste like something and hold up on a shelf, and if those jobs can be done by compounds with a plausible oral rationale rather than artificial flavors, that's a better trade.
Dr. Jen's Super Paste contains all three. We'd rather say plainly what they are: licorice has the evidence, papaya has one honest null result, and black cherry is there for flavor and antioxidant content. The active ingredient is the 10% nano-hydroxyapatite, the same conclusion the xylitol arithmetic reaches — which is why the question worth asking any brand is whose crystals those are and at what purity.
