What’s in baby wipes (and what “99% water” means)

A pack of baby wipes seems about as simple as a product gets: a damp cloth. But the cloth and the liquid it’s soaked in are both engineered, and the ingredient list, short as it is, includes a few things worth understanding. Here’s what a wipe is made of, what the “99% water” claim actually covers, and the preservative story that changed the whole category a decade ago.

A wipe is two things: a cloth and a solution

Dermatology reviews describe a wipe as having three parts: the packaging, the basesheet (the cloth itself) and the formulation (the liquid it’s soaked in). The basesheet is a nonwoven fabric, which means the fibres are bonded into a sheet rather than woven, and it’s commonly made from wood pulp, polypropylene, polyester or a mix. Different basesheets differ in thickness, softness and how well they absorb, but the fibres themselves are ordinary materials.

The formulation is where the ingredient list comes from, and it’s designed around a simple goal: lift urine and stool off skin without stripping the skin’s own protective oils.

What the liquid is made of

A review of infant skin barrier science notes that the cleansing solution in a baby wipe is more than 90% water. The remaining few percent do the actual work:

• Surfactants. These are the cleansing molecules, the same family of ingredients found in body washes. They loosen stool and oily residue so water can carry them away. Non-ionic surfactants (ones with no electrical charge) are generally the mildest on skin, and that’s what most baby wipes use.
• A pH buffer. Healthy skin is mildly acidic, and the mix of urine and stool pushes it toward alkaline, which activates stool enzymes that damage skin. Wipes commonly include an organic acid such as citric acid with its salt, sodium citrate, to hold the solution near the skin’s natural pH. A survey of North American wipes found the citric acid and sodium citrate pair in about 69% of products.
• A preservative. More on this below.
• Skin-conditioning ingredients such as glycerin (a humectant, meaning it draws water into the skin) or a thickener to keep the solution evenly spread through the cloth.
• Sometimes fragrance, and sometimes plant extracts.

One myth worth clearing up: baby wipes almost never contain drying alcohols such as ethanol or isopropanol. Ingredients with “alcohol” in the name, like fatty alcohols used as thickeners, are waxy solids that behave nothing like rubbing alcohol.

What “99% water” does and doesn’t mean

The claim is true of the liquid in nearly every wipe, including ones that don’t advertise it. It’s a statement about the formulation, not the cloth, and it says nothing about the material the sheet is made of.

More importantly, the 1% is the part that matters for skin. Water doesn’t cause allergic reactions; the preservative, the surfactant and any fragrance do. A “99% water” wipe still needs a preservative, because a warm, wet cloth is exactly where bacteria and mould like to grow. So treat the claim as a reassuring but incomplete description, and read the rest of the ingredient list anyway.

The preservative problem: what happened with methylisothiazolinone

In 2005, a preservative called methylisothiazolinone (MI) was approved in Europe at up to 100 parts per million in cosmetics, both leave-on and rinse-off. It worked well and was used widely, including in baby wipes from about 2005 to 2014.

Then dermatologists started seeing something. The European Commission’s Scientific Committee on Consumer Safety, which reviews cosmetic ingredient safety, recorded the first reports of MI contact allergy from cosmetics in 2010, mainly linked to wet wipes, shampoos, facial products and deodorants. Over the next few years, patch-test clinics across Europe reported sharply rising rates of MI sensitization.

In children, the pattern was striking. A 2014 report in Pediatrics described six children with stubborn eczema-like rashes on the buttocks, around the anus and on the face that hadn’t responded to antibiotics or steroid creams. All tested positive to MI on patch testing, all had been cleaned with MI-preserved wipes, and all cleared completely when the wipes were stopped. The authors noted that this kind of reaction is often misdiagnosed as eczema, impetigo or psoriasis.

The committee’s 2015 opinion concluded that for leave-on products, including wet wipes, no safe concentration of MI could be demonstrated, and that only a much lower level (15 parts per million) was safe in rinse-off products. Health Canada’s Cosmetic Ingredient Hotlist, the list of ingredients that are banned or restricted in cosmetics sold in Canada, now says MI is not permitted in leave-on products and caps it at 0.0015% in rinse-off ones. The same limits apply to the older blend of MI with methylchloroisothiazolinone.

Wipes count as leave-on, since you don’t rinse afterward. So in Canada, a baby wipe on the shelf today shouldn’t contain MI, though it’s still worth a glance at the label on imported products or older stock.

What preservatives are used now

The survey mentioned above found the most common preservative ingredients in North American baby wipes were sodium benzoate (in about 62% of products) and phenoxyethanol (about 48%), usually alongside the citric acid buffer, which itself helps preservation by keeping the pH low. These are among the better-tolerated options, though nothing is reaction-free for everyone. Formaldehyde-releasing preservatives, once common in wipes, have largely been dropped because they’re a known cause of contact allergy in the diaper area.

Wipes versus water and a cloth

Parents often ask whether wipes are gentler or harsher than plain water. A 2022 review in the Australasian Journal of Dermatology screened 420 papers and analyzed 21 studies. Most of them rated wipes as equal or superior to water and cloth for skin pH, water loss and redness in the diaper area. The reviewers were careful, though: many of those studies were funded by wipe manufacturers, so they declined to draw a firm conclusion. A review by manufacturer scientists reaches the same “equal or better” verdict, with the same caveat about who paid.

The fair summary is that both methods work, and neither has been shown to cause more diaper rash. Choose based on what you find practical.

What to look for on the label

The allergens that turn up most often in wipe research are fragrance (including individual fragrance components such as linalool), the surfactant cocamidopropyl betaine, formaldehyde-releasing preservatives, and MI or its blend. So:

• Pick fragrance-free, and check that the list doesn’t include fragrance components under other names.
• Skip anything listing methylisothiazolinone or methylchloroisothiazolinone.
• If your baby’s bottom stays red despite frequent changes, try a different wipe or plain water for a week before assuming it’s ordinary diaper rash.
• A rash around the anus, on the buttocks or on the face (where wipes are often used) that won’t clear with the usual care is exactly the pattern that turned out to be wipe allergy in the paediatric cases, and it deserves a doctor’s look, possibly with patch testing.

You can compare fragrance-free options in our baby care listings.

A baby wipe is mostly water by design, and that part of the label is accurate. The part that decides how skin reacts is the short list of everything else: a mild cleanser, a preservative that isn’t an isothiazolinone, a pH buffer, and ideally no fragrance. Get those right and wipes are as gentle as the research can show; if a rash won’t follow the usual script, stop the wipes for a while and ask your doctor or pharmacist.