Allantoin

Also known as: 5-ureidohydantoin, glyoxyldiureide, aluminum dihydroxy allantoinate

Evidence under review. — Not yet rated

Skin-soothing compound found in plants. Topically may help with rosacea and wound healing; oral evidence is very limited.

What it does

Allantoin is a naturally occurring compound found in many plants, including comfrey, and is also produced in the human body as a byproduct of uric acid metabolism. Topically, it is used in...
Evidence quality

Evidence base hasn't been formally rated yet. See research below.
Clinical dose

No established dose

See full breakdown ↓ Methodology →

What the Science Says

Allantoin is a naturally occurring compound found in many plants, including comfrey, and is also produced in the human body as a byproduct of uric acid metabolism. Topically, it is used in skincare formulations to soothe irritation, support skin barrier repair, and reduce redness — with one clinical trial showing benefit in rosacea patients. In animal research, oral allantoin has been explored for blood sugar effects, but no human clinical trials support this use.

What It Doesn't Do

No proven blood sugar benefits in humans — only rat studies so far. Not a treatment for diabetes. No evidence it works as a standalone oral supplement for any condition. The skin benefits seen in studies used multi-ingredient gels, so allantoin alone may not be responsible for results.

Evidence-Based Benefits

Topical allantoin-containing gel improved redness, itching, and skin barrier in rosacea patients over 12 weeks.

Weak Evidence

Effective at: No established dose

Supporting studies (click to view on PubMed):

PMID 40177799

Urinary allantoin is a measurable marker of oxidative stress that decreases with interventions like kangaroo mother care.

Weak Evidence

Effective at: No established dose

Supporting studies (click to view on PubMed):

PMID 41771956 PMID 35565914

In diabetic rats, oral allantoin lowered blood glucose, but no human trials confirm this effect.

Weak Evidence

Effective at: 5–10 mg/kg in rats only

Supporting studies (click to view on PubMed):

PMID 42542595

Absorption & Bioavailability

Unknown for oral supplementation in humans. Topical absorption is assumed based on widespread cosmetic use but not quantified in the provided studies.

Red Flags to Watch For

Most human evidence involves topical multi-ingredient products — isolating allantoin's specific contribution is not possible from available data
Oral supplement claims (e.g., blood sugar control) are based only on animal studies with no human clinical trial support
The diabetic rat study used streptozotocin-induced diabetes, which may not translate to human type 2 diabetes
Allantoin is often a minor ingredient in complex formulations; products marketing it as a primary active may be overstating its role

Frequently Asked Questions

What does Allantoin do?

Skin-soothing compound found in plants. Topically may help with rosacea and wound healing; oral evidence is very limited.

What is the effective dose of Allantoin?

No established dose

Is Allantoin safe?

Most human evidence involves topical multi-ingredient products — isolating allantoin's specific contribution is not possible from available data

What doesn't Allantoin do?

No proven blood sugar benefits in humans — only rat studies so far.

Research Sources

PubMed
NIH DSLD

This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-11-09