Guava

BotanicalBest with a meal

What is it

Guava (Psidium guajava) is a tropical fruit and the tree that bears it. The fruit, leaf, and bark all have culinary or traditional medicinal use. Supplements typically use leaf extract or fruit concentrate.

Evidence for 3 uses

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

Vitamin C and dietary fiber from fruit

Strong Evidence

Guava fruit is a well-established source of vitamin C and fiber, supporting general nutrition.

Blood glucose (guava leaf)

Limited Evidence

Small trials suggest guava leaf tea or extract can modestly reduce postprandial glucose and HbA1c. Evidence is limited and trials are small.

Acute diarrhea (guava leaf)

Limited Evidence

Traditional and some clinical use of guava leaf for diarrhea is supported by limited modern trials, mainly in pediatric populations.

How it works

Guava fruit is rich in vitamin C, fiber, and polyphenols including quercetin and ellagic acid. Guava leaf extract contains tannins, flavonoids, and triterpenes; in traditional medicine and small modern trials it has been used for diarrhea and blood glucose support. Mechanistic data suggest alpha-glucosidase inhibition and astringent (antidiarrheal) action.

Dosage

Vitamin C in 100 g of guava fruit can exceed 200 mg. Guava leaf extract supplements typically provide 200-1000 mg/day; clinical trials of guava leaf tea for blood glucose have used variable doses.

When and how to take it

No strict timing. Leaf extract often taken with meals for glycemic effects.

2 commercial forms

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

Guava fruit concentrate or powder

Whole-food form.

Vitamin C well absorbed; polyphenol absorption variable.

Guava leaf extract or tea

Used for glycemic and digestive effects.

Tannins and flavonoids extract well in hot water.

Safety

Guava fruit is safe at usual intake. Leaf extracts generally well tolerated; mild GI symptoms occasional.

Who should be cautious

Caution with antidiabetic medications because of additive glucose lowering. Pregnancy: fruit is fine; concentrated leaf extracts less well characterized.

Interactions

May add to blood-glucose-lowering effects of antidiabetic drugs. Theoretical effects on blood pressure with high intake.

Food sources

Fresh guava fruit (100 g)

Amount
~200 mg vitamin C
%DV
220%

Guava leaf tea

Amount
varies
%DV
—

Frequently asked questions

Is guava leaf safe?⌄

Yes, in normal supplement and tea doses. Mild GI effects are occasional. People on diabetes medication should monitor blood glucose.

How much vitamin C is in guava?⌄

Guava is among the richest fruits in vitamin C, with around 200 mg or more per 100 g of fresh fruit, well above the daily recommended intake.

References

Guava on Wikidata — Wikidata link

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

Research on Guava (PubMed search) — PubMed link

Track Guava with Pilora

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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.