You may know of papaya as the orange-colored tropical fruit that’s consumed for its flavor and impressive nutrient profile, but how often do you think about its star ingredient — papain?
Papain is a special enzyme that’s found in raw papaya. It’s popular in folk medicine because of its ability to break down proteins, aid digestion and reduce inflammation.
Like bromelain, which is found in pineapple, papain is available in many forms, from capsules to topicals. The two enzymes are commonly combined in commercial products for their anti-inflammatory and pain-relieving effects.
Papain is a proteolytic enzyme that’s found in papaya. The papaya fruit, Carica papaya, actually contains several proteolytic enzymes, including papain, chymopapain A, chymopapain B and papaya peptidase A.
The most well-known enzyme of the bunch, papain, is present in the immature fruit of the female papaya plant. It’s also in the leaves, roots and latex sap of the plant.
Papain helps break down the bonds between amino acids, the building blocks of proteins. Like all proteolytic enzymes, it breaks the long chain-like molecules of proteins into shorter fragments, called peptides, and then into their components, called amino acids.
The papaya enzyme has also proven to exhibit wound-healing, infection-fighting and pain-relieving effects.
Papain supplements are used to improve gastrointestinal dysfunction and common digestive issues like bloating and constipation.
This means that even people with low stomach acid, who would usually have difficulty breaking down and digesting certain types of meat, may benefit from papain supplements.
Papain has been shown to reduce inflammation in patients with asthma, arthritis and other inflammatory conditions.
Research published in 2013 in the journal Nutrition Review indicates that proteolytic enzymes, including papain and trypsin, can break down pathogenic immune complexes and even prevent their formation in the first place.
This means that papain may be able to prevent inflammation from occurring, thereby enhancing lymphatic drainage and having regulatory effects on the immune system.
A review of literature published in the Journal of Immunotoxicology found that both in vitro and in vivo studies have shown that papaya extracts and papaya-associated phytochemicals have anti-inflammatory and immunomodulatory properties, but more clinical studies are needed to fully understand these effects.
Several studies indicate that the papaya enzyme works to relieve pain in a number of areas, including muscle pain from intense workouts, sore throat pain and pain associated with shingles.
A study published in the Journal of Clinical Pediatric Dentistry found that a papain-based gel called Papacarie was effective in removing infected tissues among patients with caries, or decaying teeth.
Studies show that the gel helps reduce pain and inflammation without the need for anesthesia or drilling during tooth removal.
A study published in the Journal of Sports Science shows that taking a protease supplement containing the papaya enzyme may help relieve muscle pain that’s caused by running.
The participants consumed protease tablets that contained 50 milligrams of papain, in addition to other enzymes like bromelain, trypsin, amylase and lipase. After taking two tablets, four times a day for four days, runners demonstrated superior recovery and reduced muscle soreness compared to the placebo group.
In addition, a 1995 German study evaluated the efficacy of an enzyme combination containing papain for herpes zoster, or shingles.
Researchers found that the enzyme preparation showed identical efficacy with acyclovir, an antiviral medication that’s used to treat herpes virus infections. The enzyme combination was able to reduce pain associated with shingles after 14 days of treatment.
An animal study conducted in Italy found that when cancerous mice were immunized with papain, they exhibited an increased mean survival time compared to the non-immunized controls.
The growth rate, invasion and metastasis of cancerous tumors were inhibited in the mice after receiving papain immunization.
Papain has been used in nontraditional wound care because of its antiviral and antifungal properties.
It appears that papain works to fight infections by destroying the layer of protein that protects fungi and viruses against attacks. This decreases their ability to reproduce, spread and cause infections.
Topical papaya enzyme products are often used for their wound-healing effects, although the FDA warns consumers about possible allergic reactions when applying the enzyme topically.
There are preliminary studies supporting the papaya enzyme’s ability to support wound healing. A 2010 animal study conducted in Malaysia found that a papain-based wound cleanser helped with wound reduction, promoted collagen deposition and exhibited antibacterial properties.
Papain is considered safe when it’s consumed in normal amounts found in foods, and it’s considered “possibly safe” when taken by mouth in appropriate amounts.
According to research published by the Mayo Clinic College of Medicine, consuming excessive amounts of the enzyme can lead to papain side effects, including stomach discomfort, throat irritation and gastritis.
There is concern about the possibility of allergic reactions when using creams or ointments made with the enzyme topically. If you have an allergy or sensitivity to papain, you may experience skin irritation, redness or blisters when you apply the enzyme to your skin.
It’s believed that people who are allergic to kiwi and fig may also be allergic to papain. People who experience allergy symptoms after being exposed to these fruits should definitely be cautious when using papain topically or internally.
Because papain may lower blood pressure, people with diabetes and hypoglycemia should use the enzyme with caution and under the care of a health care professional.
The enzyme should not be consumed or used by people who are on blood thinners, as it may increase your bleeding risk. It’s also important to avoid using it at least two weeks before any scheduled surgery.
It’s is not considered safe to use papain supplements during pregnancy or while nursing.
Papain is available in several forms, including as capsules, tablets, powders, chewable gummies, creams and ointments.
There are no official guidelines for the use of papain. Dosages that fall between 25–100 milligrams daily are generally considered safe.
It’s best to consult your health care professional before using papain in order to pinpoint an appropriate dosage for your health needs.
Consuming too much papain can lead to adverse side effects, so avoid exceeding 400 milligrams per day, unless advised otherwise by your doctor. There is some evidence that taking higher amounts (up to 1,500 milligrams per day by mouth) of the enzyme can be beneficial, but this should be approved by your doctor.
Papain topicals, including creams and ointments, can be applied to areas of inflammation, redness, burning sensation and pain. Before using the topical on a large surface area, perform a patch test to rule out an allergy or sensitivity to the enzyme.