Actinidin

EnzymeProtease

What is it

Actinidin is a cysteine protease enzyme found in kiwifruit (Actinidia deliciosa, A. chinensis). It is similar to bromelain (from pineapple) and papain (from papaya), and is included in some digestive enzyme supplements and used as a meat tenderizer.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Protein digestion support

Limited Evidence

Some clinical evidence suggests kiwifruit/actinidin improves digestion of complex proteins, particularly in people with reduced gastric function.

How it works

Actinidin breaks down protein into smaller peptides and amino acids. In the gastrointestinal tract, it may aid digestion of dietary protein, particularly under conditions of reduced endogenous protease activity. Studies suggest actinidin specifically enhances gastric and small intestinal protein digestion, particularly of complex proteins like soy and meat. Outside of digestion, kiwifruit (which contains actinidin) has been studied for laxative effects and gut microbiome effects, though these are more often attributed to the fiber content than to actinidin per se.

Dosage

No established RDA for the enzyme. Kiwifruit consumption (1-2 fruit/day) provides natural actinidin. Supplement doses vary.

When and how to take it

WHEN: With protein-containing meals for digestive support. HOW: As kiwifruit, or in enzyme supplement form.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Actinidin (enzyme supplement)

Used in digestive enzyme formulations.

Active in stomach acid range

Kiwifruit (natural source)

Most common consumption form.

Whole-food source with fiber and other compounds

Safety

Generally well tolerated. Actinidin is a known allergen in kiwifruit; people with kiwifruit allergy or oral allergy syndrome (often cross-reactive with latex, banana, avocado) should avoid.

Who should be cautious

Avoid in kiwifruit allergy. People with latex-fruit syndrome should be cautious.

Interactions

May enhance absorption of some compounds via increased GI protein breakdown. Limited specific drug interaction data.

Food sources

Kiwifruit (green)

Amount
1 medium fruit
%DV
—

Kiwifruit (gold) - lower actinidin

Amount
1 medium fruit
%DV
—

Frequently asked questions

Does actinidin help digestion?⌄

It may aid protein digestion, particularly in people with reduced gastric function. The effects from eating whole kiwifruit are modest but useful.

Is gold kiwifruit different?⌄

Yes, gold kiwifruit contains less actinidin than green kiwifruit and is less likely to cause oral allergy reactions.

References

Actinidin on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Actinidin (PubMed search) — PubMed link

Track Actinidin with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.