Research review
Does papaya enzyme help with inflammation? What the research does and doesn't show
No trial has tested papain by itself against a placebo for inflammation. Three small human trials found a measurable difference on an inflammation-related outcome using papain combined with other ingredients — a leaf-extract toothpaste, a five-ingredient supplement, and a papaya-and-oats product for gastritis — none isolating papain's own contribution.
The evidence doesn't support papain, taken alone, as an anti-inflammatory in people — every relevant human trial found tested papain as one ingredient in a multi-ingredient blend or product, not by itself, which means none of them can say what papain's own contribution was. Three small trials found a measurable difference on an inflammation-related outcome; none isolated papain to prove it caused the result.
What the evidence doesn't support
It doesn't support papain by itself, at a stated dose, as something that reduces inflammation in a general population — no trial testing plain papain alone against a placebo for an inflammation marker was found. Every human trial below combined papain with other active ingredients, so none of them can be read as evidence for papain on its own, and none of them measured a chronic inflammatory disease outcome like arthritis.
What the trials found
A 2018 randomized, single-blind trial gave 100 people a toothpaste containing papaya leaf extract, either alone or paired with a matching mouthwash, and compared them with a standard enzyme-containing toothpaste with or without an essential-oil mouthwash. Gingival bleeding — a marker of gum inflammation — dropped substantially in every group over four weeks, and the papaya-leaf toothpaste performed about the same as the standard comparison toothpaste; within the papaya-leaf group specifically, adding the matching mouthwash brought bleeding sites down further than the toothpaste alone (21% versus 32%, a difference the trial called statistically significant). This tested a leaf extract, not papain, and there was no placebo (untreated) group — both study arms used an active oral-care product.
A 2017 open trial gave 24 healthy adults a supplement called Infla-Kine — a blend of fermented lactobacillus extract, burdock seed, zinc, alpha-lipoic acid, papaya enzyme and a curcumin complex — twice daily for four weeks, with blood and immune-cell samples taken before and after. Several inflammation-related gene readings in blood cells, and a marker called CRP, were lower after four weeks than before; participants also reported general well-being improvements, most often around muscle and joint discomfort. There was no placebo group in this design, so a change over time can't be separated from other explanations, and because Infla-Kine has five active ingredients, papain's own share of any result can't be determined from this trial.
A 2018 double-blind, placebo-controlled trial gave 60 people with doctor-diagnosed mild chronic gastritis — inflammation of the stomach lining — either a papaya-and-oats product called Caricol-Gastro or a placebo, twice daily for 30 days. Pain scores improved in both groups, which the authors describe as a strong placebo effect, but the papaya-and-oats group's pain reduction was larger, by a margin the trial reported as statistically significant though modest. This combined papaya with oats, not papain alone, and the effect size was small enough that the authors framed it as a supportive add-on to standard care, not a replacement for it.
Questions people ask
Does papaya enzyme help with inflammation?
No trial testing papain by itself for inflammation was found. Three small trials found a difference on an inflammation-related measure using papain combined with other ingredients — a toothpaste with papaya leaf extract, a five-ingredient supplement, and a papaya-and-oats product — but none isolated papain's own contribution.
Is papaya enzyme anti-inflammatory?
Papain has documented protein-breaking activity in lab research, and researchers have used that activity to study how proteases affect body tissue — but that's a lab mechanism, not the same as a demonstrated anti-inflammatory effect from swallowing a papain supplement. See papaya enzyme and GERD or IBS for lab research on this same enzyme class and gut-lining tissue, which cuts in a more cautionary direction.
Does papaya enzyme help with arthritis or joint pain?
No trial testing papain, alone or in a blend, in people with a diagnosed arthritis or joint condition was found. One small open trial of a five-ingredient supplement that included papain found participants reported general well-being improvements most often around muscle and joint discomfort, but with no placebo group and four other active ingredients in the mix, that finding can't be attributed to papain specifically.
When to talk to a doctor
Ongoing joint pain, gum disease, chronic gastritis or any other persistently inflamed area is worth evaluating with a doctor or dentist rather than working through with a supplement search — papaya enzyme products are not a treatment for a diagnosed inflammatory condition. If you're on a prescribed anti-inflammatory medication or have a diagnosed inflammatory disease, talk to your doctor before adding any new supplement.
Related reading: papaya enzyme and GERD or IBS: what the research shows, papaya enzyme: what the research does and doesn't show, and papaya enzyme side effects.
Sources
- Effect of a Toothpaste/Mouthwash Containing Carica papaya Leaf Extract on Interdental Gingival Bleeding: A Randomized Controlled Trial A 2018 randomized trial found gum bleeding dropped substantially over 4 weeks in every group tested, and a papaya-leaf-extract toothpaste performed about the same as a standard comparison toothpaste; adding a matching mouthwash to the papaya-leaf toothpaste reduced bleeding sites further than the toothpaste alone. This tested leaf extract, not papain, with no untreated placebo group.
- Effect of Infla-Kine supplementation on the gene expression of inflammatory markers in peripheral mononuclear cells and on C-reactive protein in blood A 2017 open trial (no placebo comparison) found several inflammation-related gene markers in blood cells, and a marker called CRP, were lower in 24 healthy adults after 4 weeks of a five-ingredient supplement containing papaya enzyme than before starting it; participants also reported general well-being improvements, most often around muscle and joint discomfort. With five active ingredients and no placebo group, papain's own contribution can't be determined from this trial.
- Supplementation of Caricol®-Gastro reduces chronic gastritis disease associated pain A 2018 placebo-controlled trial found a papaya-and-oats product produced a larger reduction in gastritis-related pain scores than placebo over 30 days, on top of a large improvement in both groups the authors call a strong placebo effect; this combined papaya with oats, not papain alone, and the trial's own authors describe it as a supportive add-on, not a replacement for standard care.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.