Allantoin: the soothing ingredient in so many balms

Turn over almost any lip balm, diaper cream or “soothing” ointment and there’s a good chance you’ll find allantoin in the ingredient list. It’s been used on skin for a very long time, it has an official health claim in Canada, and it has an excellent safety record. What it doesn’t have is much modern clinical evidence. Here’s the full picture.

What is allantoin?

Allantoin is a small, simple molecule made of carbon, hydrogen, nitrogen and oxygen. According to the US National Library of Medicine’s chemical database, it’s found in plants, famously the comfrey plant, and in the urine of many mammals. In those animals it’s what’s left when the body breaks down uric acid. Humans skip that step and get rid of uric acid as it is.

The same database notes it has long been used for its soothing, anti-irritating properties. A molecule is a molecule: allantoin works the same way whatever its source.

It’s an odourless white powder, and it turns up almost everywhere. A US safety review counted it in 1,376 cosmetic products, and that was back in 2010.

Why Health Canada calls it a skin protectant

Allantoin is one of the medicinal ingredients listed in Health Canada’s Medicated Skin Care Products Monograph. A monograph is a pre-approved set of rules: products that follow it can be licensed without the company submitting new evidence. The monograph allows allantoin at between 0.5 and 2 percent of the product.

Products that meet the rules can claim to:

• temporarily protect and help relieve minor skin irritation and itching
• temporarily protect and help relieve minor irritation and itching due to minor cuts, scrapes and burns

These claims mirror the US FDA rules for skin protectants, which the monograph cites. On a Canadian label, you’ll see allantoin listed as a medicinal ingredient and an NPN (Natural Product Number) if the product is licensed this way.

Notice what the claims say and don’t say. “Protects and helps relieve” is about comfort, not repair. The monograph also says not to use these products on deep or puncture wounds, animal bites or serious burns, and to see a health care provider if symptoms get worse or last more than seven days.

What does the evidence actually show?

This is where allantoin gets humbler. Most of the evidence is old, comes from animals or is mixed in with other ingredients.

Lab and animal studies

A 2010 study in 60 rats compared wounds treated with an allantoin lotion, the same lotion without allantoin, and no treatment. The allantoin wounds healed faster, and under the microscope there were signs of calmer inflammation and more fibroblast activity (the cells that rebuild skin). It’s a useful clue about how allantoin might work, but rat wounds aren’t human skin.

The biggest human trial

The largest well-designed trial of allantoin didn’t look at everyday irritation at all. It tested a high-strength allantoin cream in 169 children and adults with epidermolysis bullosa, a rare genetic condition in which the skin blisters and tears very easily. Over three months, the allantoin cream was no better than the same cream without allantoin at closing wounds. It was well tolerated. The trial was sponsored by the company developing the cream, which makes the negative result all the more believable.

That doesn’t prove allantoin does nothing for a chapped lip. It does show that when allantoin was put to a rigorous test on hard-to-heal wounds, the cream base did just as well.

Sensitive skin products

A 2022 review from the University of Porto looked at 88 facial products labelled for sensitive skin and ranked their active ingredients. Allantoin came third, after niacinamide and oat. But the review found that clinical studies on these ingredients are sparse and often poor quality, and allantoin was not among the few ingredients actually tested on people with sensitive skin.

So the honest evidence level is: very widely used, officially accepted as a protectant, plausible from animal work, but with little modern human evidence that it adds much beyond the moisturizing base it comes in.

Is allantoin safe?

Here the news is very good. The 2010 review by the Cosmetic Ingredient Review expert panel, a US scientific body that assesses cosmetic ingredient safety, concluded that allantoin is safe as used in cosmetics. Health Canada’s monograph allows allantoin skin protectants for everyone from newborn infants to adults.

In our search of the medical literature, reports of allergy to allantoin itself were hard to find, especially compared with ingredients like fragrance or some preservatives. If you react to an allantoin product, the likelier culprit is something else in the formula.

How to think about allantoin when you shop

• See it as a gentle extra. Allantoin won’t hurt, and it may add a little comfort, but the base of the product does most of the work.
• The base matters most for chapped skin. Ointments and balms that seal in moisture are what really help cracked lips, knuckles and noses in a Canadian winter.
• Check the rest of the label. A “soothing” balm with fragrance or flavouring can still irritate sensitive skin.
• Know when to stop. If a rash, scrape or burn isn’t better within a week, or is getting worse, see your doctor or pharmacist.

You can browse balms and ointments reviewed by the panel or filter for products suited to sensitive skin.

Allantoin is one of the gentlest, most familiar ingredients in skin care, with an official Canadian claim for relieving minor irritation. The evidence that it does more than the cream around it is thin, and the best trial came up empty. That’s no reason to avoid it, just a reason to choose a balm for its base, its fragrance-free label and how it feels, rather than for the allantoin alone.