Water-free formulas: why some balms contain no water at all

Look at the ingredient list of a lip balm, a healing ointment or a hand salve and you may notice something missing: water. Most creams and lotions list “aqua” first; a balm often lists an oil, a wax or petrolatum instead. That one difference changes almost everything about how the product behaves, how it’s preserved and what it’s good for.

What “anhydrous” means

Anhydrous simply means “without water”. An anhydrous product is built entirely from oils, butters, waxes and other water-free ingredients. Petroleum jelly is the simplest example; a beeswax and shea butter lip balm is another.

Creams and lotions, by contrast, are emulsions: mixtures of water and oil held together by an emulsifier. Lotions have the most water, creams a bit less, and ointments the least, often none at all. The UK’s National Eczema Society uses this same ladder to explain why they feel and work so differently.

The amount of water is the single biggest predictor of how a moisturizer behaves. More water means a lighter, cooler feel that absorbs fast, but also a product that needs preserving and evaporates off the skin. Less water means a heavier feel, longer staying power and less need for preservatives.

Why water-free products can skip preservatives

Microbes need water. Bacteria, yeasts and moulds can’t multiply without free water to live in, which is why a jar of honey lasts for years and a jar of cut fruit doesn’t. Cosmetic microbiologists measure this as water activity: a scale from 0 to 1 that describes how much water in a product is actually available to organisms, rather than bound up with other ingredients.

A 2025 technical guide from the German Society for Scientific and Applied Cosmetics sums up the thresholds. Most bacteria can’t grow below a water activity of about 0.91. Moulds and yeasts are hardier, but 0.60 is generally taken as the cut-off below which almost nothing proliferates. Products at or below 0.75 are classed as “low risk” under the international standard ISO 29621 and usually skip the challenge testing (deliberately adding microbes to see if the preservative kills them) that a lotion must pass.

A lotion sits well above 0.9. A balm made only of oils and waxes sits near zero. That’s why an anhydrous product can legitimately be sold with no preservative at all, and why “preservative-free” claims are most trustworthy on exactly this kind of product.

Two honest caveats:

• Water added during use is the weak point. The same guide warns that water-free formulas can carry dormant bacterial or fungal spores, and if water gets in (wet fingers in a jar, a steamy bathroom, a lid left off), those spores can wake up. Jars are more exposed than tubes.
• “No preservative” doesn’t mean “sterile”. In a 2018 survey by US FDA scientists, 93 eye-area cosmetics sold as natural, paraben-free or preservative-free were tested. Sixty per cent were free of microbial growth, 32 per cent had low levels and 8 per cent had higher levels, mostly harmless soil bacteria that likely came from natural raw materials. Lower-water-activity products were actually more likely to carry some microbes, because they relied on dryness alone.

For a balm you scoop with clean, dry fingers and use up within months, none of this is alarming. Keep the lid on and the jar dry.

Why they seal better, and why they feel heavier

Oils, waxes and petrolatum are occlusive: they form a film on the skin that slows water from evaporating out of it. The less water a product contains, the more concentrated that film is. That’s why the National Eczema Society describes ointments as the most effective choice for very dry and thickened skin, and why they’re often applied at night or under wet wraps.

The trade-off is feel. The same source is blunt: ointments are “often stiff and greasy, and some people may find them cosmetically unacceptable”. They don’t absorb, they can transfer to clothes and sheets, and in warm weather they can feel like a layer of plastic wrap.

There’s a second trade-off that’s easy to miss. An anhydrous balm can’t hydrate skin on its own, because it has no water to give and usually no humectant (a water-attracting ingredient such as glycerin or urea) to pull water in. What it does is keep the water already in your skin from leaving. The American Academy of Dermatology’s advice for petroleum jelly applies to any balm: put it on while your skin is still damp, so it seals moisture in rather than sitting on top of dry skin.

When a water-free balm is the right tool

Water-free formulas shine where you need a durable, protective film and don’t mind the feel:

• Very dry or cracked patches. Knuckles, heels, elbows and the dry plaques of eczema (the itchy, inflamed skin condition) respond well to an ointment applied over damp skin, especially at bedtime.
• Lips. There’s no water to evaporate, no preservative to sting, and the film lasts through a cold walk. In a Canadian winter, this is the classic use.
• Hands that get washed a lot. The Eczema Society of Canada suggests moisturizing after each hand wash if you have hand eczema; a thick balm holds up to that better than a lotion.
• Minor scrapes and healing skin. The AAD recommends keeping small wounds moist with plain petroleum jelly. The same logic is behind the thin layer of plain ointment often used on a fresh tattoo; follow your artist’s instructions, keep it thin, and if the skin gets red, hot or oozy, see your doctor.
• Skin that reacts to preservatives. If patch testing has shown you’re allergic to common preservatives, a well-made anhydrous product sidesteps the problem entirely. The National Eczema Society notes ointments contain fewer preservatives for exactly this reason.

If you want to browse the format, the Panel’s reviewed balms and ointments are listed by category.

When it isn’t

A greasy, occlusive film is the wrong tool for some skin:

• Weeping or oozing eczema. The National Eczema Society says ointments should not be used on weeping eczema; lotions or creams are better there until the skin dries.
• Acne-prone areas. The AAD advises keeping petroleum jelly off your face if you’re prone to breakouts, and the same caution applies to heavy balms generally, since they seal in whatever is underneath.
• Hot, humid weather or sweaty skin. The film traps heat and sweat, and can feel suffocating.
• Skin that’s simply dehydrated. If your skin is tight and dull rather than cracked and flaky, it needs water and a humectant more than a seal. A cream, or a humectant serum with a balm on top, does more.

Choosing between a balm and a cream

The Eczema Society of Canada’s guidance is the sensible tie-breaker: the best moisturizer is the one you’re willing to use often enough to keep your skin comfortable. For many Canadians that means a cream by day and an ointment at night, or a lotion in July and an ointment in January. The Society’s winter advice is exactly that: swap lotions for creams, or turn to a rich ointment, when cold outdoor air and dry indoor heat set in.

Whatever you pick, apply it to damp skin, keep it fragrance-free if your skin is reactive, and patch test a new product on a small area first.

The short version: a water-free balm gives microbes nothing to grow in, so it can be sold with little or no preservative, and its oil-and-wax film is the best at holding water in. Those same qualities make it heavy, non-hydrating and unsuited to weeping or acne-prone skin. Match the format to the job, and both balms and creams earn their place.