Panthenol: a water soluble active in a product with no water
D panthenol is a viscous liquid that will not dissolve in an oil phase. Use at 0.5 to 5 percent, the solubiliser options, and what the evidence supports on lips.
Panthenol is the most requested active on lip balm ingredient lists and one of the least likely to be sitting where the formulator thinks it is. It is a syrup that mixes with water in any proportion and with vegetable oil in almost none, so stirring it into a melted wax and butter base produces a suspension at best and a wet plug at the bottom of the tube at worst. This page covers what the material actually is, why the D form is the only one worth buying, the three ways it fails in a balm, the carriers that fix each one, and how much of the clinical evidence transfers to lips.
D panthenol (INCI Panthenol, CAS 81-13-0) is a hygroscopic syrup of about 6000 mPa s at 20 C and density near 1.20 g/mL, miscible with water and practically insoluble in oils. Use 0.5 to 1 percent in a lip balm and up to 5 percent only in a lanolin or petrolatum ointment base, always pre-dissolved in propanediol or carried in an oil dispersion.
What panthenol is, and why only the D form counts
Panthenol is the alcohol analogue of pantothenic acid, vitamin B5. Skin enzymes oxidise it to pantothenic acid, which is the precursor of coenzyme A, the cofactor that sits at the centre of fatty acid synthesis. That is the mechanistic story behind every barrier repair claim made for the material: not that panthenol is itself an occlusive or a meaningful humectant at the levels used, but that it feeds a pathway the skin uses to rebuild lipids.
The molecule has a chiral centre, and the two enantiomers are not interchangeable. Only the D form, dexpanthenol, is converted to biologically active D pantothenic acid. The L form is not, and is treated as inert in that pathway. Commercial material therefore comes in two grades that share a name and behave differently:
- D panthenol (dexpanthenol, CAS 81-13-0). A clear, colourless, very viscous hygroscopic liquid. This is the pharmacopoeial material, with monographs in both the European Pharmacopoeia and USP-NF under the name dexpanthenol.
- DL panthenol (racemic, CAS 16485-10-2). A white crystalline solid, not a syrup. Half of it is the inactive L enantiomer, so 5 percent of DL panthenol delivers 2.5 percent of active material, and because it is a crystal rather than a liquid it introduces a grit risk in a balm that the D form does not have.
DL panthenol is cheaper per kilogram and common in hair products, where the difference matters less. In an anhydrous balm it is the wrong choice twice over: you are paying to disperse an insoluble crystalline powder, with the same particle size problem covered in allantoin, and half of it does nothing. Buy D panthenol and check that the certificate of analysis names dexpanthenol.
The physical properties that decide everything else
Almost every problem on this page follows from three numbers: the viscosity, the density and the solubility profile.
| Property | Value | Why it matters in a balm |
|---|---|---|
| INCI name | Panthenol | Covers both D and DL grades, so the label does not tell a buyer which was used |
| Molecular formula | C9H19NO4 | Three hydroxyl groups, one amide. Strongly polar, which is the root of the problem |
| Molecular weight | 205.3 | Small enough to move into the stratum corneum rather than sit on it |
| Physical form, D grade | viscous liquid | Pours slowly, drips off a spatula for a long time, weighs badly at small scale |
| Viscosity | about 6000 mPa s | Roughly honey-like. It does not thin usefully until well above 40 C |
| Density | about 1.20 g/mL | Around 30 percent denser than the oil phase, so droplets sink rather than float |
| Water | miscible | Any ratio. This is the form the clinical literature almost always uses |
| Ethanol, propylene glycol, propanediol, glycerin | soluble | The practical carrier route in an anhydrous product |
| Vegetable oils, esters, mineral oil | practically insoluble | Below roughly 0.1 percent. Everything above that is dispersed, not dissolved |
The last row is the one people argue with, and it is not negotiable. Polarity decides solubility, panthenol carries three hydroxyls and an amide on nine carbons, and a triglyceride offers nothing to hydrogen bond with. The general framework is in what dissolves in an anhydrous balm, and panthenol sits in the same class as glycerin, urea and sodium hyaluronate rather than with tocopherol or an oil soluble ester.
Why it separates: the arithmetic of a sinking droplet
A balm is only a solid at the end. For the several minutes between the last stir and the point where the wax network sets it is a thin liquid of roughly 30 to 60 mPa s, and a dense insoluble droplet has that whole window to travel.
Take Stokes' law with a density difference of 0.29 g per mL between panthenol and the oil phase, and a melt viscosity of 50 mPa s. A 100 micrometre droplet settles at roughly 2 mm per minute. In a lip tube standing upright while it cools for eight minutes, that is more than a centimetre of travel, which is why the fault so often appears as a wet, sticky plug at the base of the stick rather than as visible droplets throughout. Drop the droplet size to 10 micrometres and the same arithmetic gives about 0.02 mm per minute, which is nothing over the life of a batch. Droplet size, not solubility, is the variable you can actually control.
Once the balm has set, the yield stress of the crystal network is far more than enough to hold a droplet of any size in place, for the reasons set out in rheology and yield stress. That is why fast cooling helps and slow cooling hurts, and why the same formula behaves differently in a warm room than in a cold workshop.
The three failure modes, and what each one looks like
Makers describe panthenol failures in three ways, and they are three distinct mechanisms with three different fixes.
- Separation. A discrete syrupy layer at the bottom of a tin or the base of a tube, sometimes clear, sometimes cloudy. Cause: large droplets, a long cooling window, a base with no polar component. This is the version diagnosed in balm separated in layers.
- Bleed. Fine beads appearing on the surface of a set balm over days or weeks, most obviously in a tin left in a warm room. The mechanism is the same one that produces oil sweating, and the diagnosis in balm sweating applies directly, with the difference that panthenol beads are sticky rather than slippery and do not reabsorb when you warm the tin.
- Tacky surface. No visible droplets, but the stick feels sticky and picks up crumbs and lint. This one is hygroscopicity rather than separation, and it appears at high loadings even when the dispersion is perfect.
Panthenol 75W is 75 percent panthenol and 25 percent water. Adding 4 percent of it to an anhydrous balm adds 1 percent free water, which is enough to move the product out of the water activity band that makes it self preserving. If you use a diluted grade, read do balms need preservatives first, and understand that you have made an unpreserved low water product rather than an anhydrous one.
Carriers that actually work
There are four routes, in rough order of how well they hold up in a small workshop.
Pre-dissolve in propanediol. Propanediol (or propylene glycol, or glycerin, if you already accept the tackiness) dissolves panthenol readily. Make a solution of one part panthenol to two parts propanediol, warm gently to about 40 C to get it clear, and add that to the melt. The solution is still a polar phase and still insoluble in the oils, but it is far less viscous than neat panthenol, so it breaks into much smaller droplets under the same stirring. Keep the total polar load below about 3 percent of the formula, which is the same ceiling that applies to glycerin and humectants.
Add a polyglyceryl ester. A water in oil emulsifier such as a polyglyceryl-3 or polyglyceryl-4 ester of a fatty acid, at 1 to 3 percent, lowers the interfacial tension enough that ordinary stirring produces droplets in the tens of micrometres rather than the hundreds. This is the single most effective change you can make, and it is what commercial anhydrous balms carrying 2 percent or more panthenol are doing. The trade is a small softening of the stick and a slightly slicker feel.
Buy an oil dispersion. Panthenol supplied at around 50 percent in caprylic capric triglyceride with a dispersant already in it is not a solution, but the particle size work has been done at a scale you cannot match with a spatula. Weigh it like an oil, add it late, and stir. The trade is that you are buying half a drum of caprylic capric triglyceride at the price of an active.
Lean on a polar base. Castor oil and lanolin hold small quantities of polar material far better than triglycerides do, castor because of the hydroxyl on ricinoleic acid and lanolin because it is a mixture of sterol esters and free alcohols. A balm carrying 15 percent castor oil or 5 percent lanolin tolerates roughly twice the panthenol of a plain wax and sunflower base before it bleeds. This is also the reason the classic 5 percent dexpanthenol ointment works: its base is petrolatum, lanolin and wool alcohols, not a wax and vegetable oil stick.
Make a 20 g test melt of your base, add the panthenol at your target level, hold it molten and stir for two minutes, then pour half into a tube and leave the other half in the jug. If the jug residue shows a syrupy layer within ten minutes, the batch will separate in the tube too. This costs one melt and saves a run of a hundred sticks.
How much to use, by product
The 0.5 to 5 percent window quoted on supplier data sheets is real, but it is a window for cosmetics in general, and the top of it belongs to emulsions and gels. In an anhydrous product the practical ceiling is set by the base.
| Product | Panthenol | Carrier needed | Limiting factor |
|---|---|---|---|
| Lip balm, twist tube | 0.5-1% | Propanediol solution, or a polar base | Surface tack and the plug at the base of the stick |
| Lip balm, tin or pot | 0.5-2% | Propanediol solution plus a polyglyceryl ester above 1% | Bleed onto the surface in a warm room |
| Overnight lip mask | 1-3% | Polyglyceryl ester or an oil dispersion | Tack is partly wanted here, so the ceiling is higher |
| Face or body balm | 1-3% | Polyglyceryl ester | Slip and afterfeel |
| Petrolatum or lanolin ointment | 2-5% | None, if the base is at least 40% petrolatum and lanolin | Little. This is the vehicle the clinical work used |
| Plain wax and vegetable oil stick, no carrier | below 0.3% | None available | Anything more separates within a week |
Weighing at these levels is its own problem. One percent of a 60 g batch is 0.6 g of a syrup that clings to the spatula, so a scale reading to 0.01 g and a tared addition straight into the melt beat any technique. Scaling arithmetic is in the batch calculator, and the base method is in how to make lip balm.
Panthenyl triethylhexanoate, the oil soluble alternative
If the separation problem is the only thing standing between you and the ingredient list you want, there is a material that removes it entirely. Panthenyl triethylhexanoate is the triester of panthenol with 2-ethylhexanoic acid, formed on all three hydroxyls. Esterifying away the hydroxyls removes the polarity, and the result is a thin, colourless, fully oil soluble liquid that behaves like an emollient ester in the melt.
| Property | Panthenol | Panthenyl triethylhexanoate |
|---|---|---|
| Solubility in the oil phase | Practically none | Miscible |
| Separation risk | High without a carrier | None |
| Feel at 2 percent | Tacky, slightly draggy | Light, dry, faintly silicone-like |
| Panthenol delivered per 1 percent used | 1.0% | 0.35% at most |
| Needs skin enzymes to work | No | Yes, esterases must hydrolyse it first |
| Depth of clinical evidence | Substantial, on dexpanthenol | Thin, mostly manufacturer studies |
| Typical use level | 0.5-5% | 0.5-3% |
The honest reading is that the triester solves a formulation problem and buys an evidence problem. Three percent of it delivers at most the equivalent of one percent panthenol, and only if skin esterases cleave all three ester bonds, which is assumed rather than demonstrated at the rate the marketing implies. It is a good choice in a clear lip oil or a light face balm where any tack is unacceptable. It is a poor choice if the reason you are adding panthenol at all is that you want the material the trials used.
Hygroscopicity and the sticky stick
Panthenol is strongly hygroscopic, which is the property that makes it a humectant and also the property that makes a lip balm feel like sticky tape. Droplets that reach the surface of the product pull water out of the air and stay wet. At 0.5 percent, spread through a set balm, this is invisible. At 3 percent in a twist tube, the exposed face of the stick develops a permanently tacky skin that grabs lint, and customers report it as the balm having gone off when nothing has degraded. That specific complaint, and the other causes of it, are triaged in sticky and tacky balm.
The humectant argument also deserves stating carefully. A humectant attracts water from wherever water is available, which in a balm means the atmosphere and the skin beneath. In a low humidity environment the gradient can run the wrong way, which is the standard caution about glycerin and applies here in weaker form because panthenol is a milder humectant than glycerin. The categories are separated properly in occlusive, emollient and humectant. In practice the occlusive film of the balm is doing the overwhelming share of the measurable work, as transepidermal water loss sets out, and panthenol is a small increment on a large effect.
What the clinical evidence supports
Dexpanthenol has a better evidence base than most cosmetic actives and a narrower one than its reputation suggests. The controlled work that matters used 5 percent dexpanthenol in a lipophilic ointment, applied to forearm skin whose barrier had been deliberately damaged with sodium lauryl sulphate, and measured transepidermal water loss, erythema and skin roughness against the same ointment without the active. In that model the active arm recovered faster than vehicle. A review in the American Journal of Clinical Dermatology in 2002 collected the dermatological uses and reached a similar position: modest, real, best supported for barrier disruption and for the aftercare of superficial insults.
Four limits sit around that. The concentration was 5 percent, which is at or above the top of what an anhydrous lip stick can carry. The vehicle was an ointment, which is itself strongly occlusive, so the trials measure an increment on top of a good base rather than a standalone effect. The site was forearm skin, not lip vermilion, which has a thinner stratum corneum, almost no sebaceous glands and a completely different exposure pattern. And the endpoint was recovery from experimental irritation, not the everyday chapping most people buy a lip balm for. What genuinely helps habitually chapped lips is set out in ingredients for chapped lips, and occlusion leads that list by a wide margin.
In the UK and much of the EU, 5 percent dexpanthenol ointments are licensed medicines, not cosmetics. That licence is what allows them to talk about wound healing and nappy rash. A cosmetic balm containing the same active may not borrow those claims, whatever the concentration. The boundary and the wording that crosses it are in cosmetic versus drug claims.
Heat, colour and when to add it
Panthenol is chemically stable in an anhydrous environment. The hydrolysis to pantothenic acid that dominates its stability profile in water needs water to happen, so a dry balm removes the main degradation route and shelf life is governed by the oils rather than the active. What panthenol does not tolerate is prolonged heat: held above roughly 70 C it yellows and eventually browns, and the discolouration is permanent.
Add it off the heat, at the lowest temperature at which the base is still fluid. For a beeswax lip formula that is usually 60 to 65 C and only a minute or two before the pour, which conflicts with the pour temperature guidance in pour temperatures less than it appears: you are adding a fraction of a percent of a room temperature liquid to a hot melt, and the temperature drop is negligible. Stir for a full minute after adding, because the viscosity means a quick swirl leaves a rope of syrup rather than a dispersion.
Store the drum sealed. An open container picks up atmospheric moisture steadily, and a tub that has absorbed several percent water is both weaker than the label says and a route for water into products meant to have none.
The decision rule
Panthenol earns a place in an anhydrous product in two situations. The first is a thick, occlusive treatment balm built on petrolatum or lanolin, where 3 to 5 percent goes in without a fight and the vehicle resembles the one the trials used. The second is a lip or face balm at 0.5 to 1 percent with a proper carrier, where the honest description is a small addition to a base already doing the work.
It does not earn a place at 0.1 percent in a plain wax and oil stick added so the ingredient list reads better. That level is below anything the evidence tested by a factor of thirty, and the money is better spent on the occlusive load. It does not earn a place at all if you are not prepared to buy either a solubiliser or an oil dispersion, because neat panthenol stirred into a melt will separate, and a product that separates is a worse product than one without the active. And if the tack is the thing you cannot accept, use the triester and describe it accurately, rather than pretending the two materials are the same. The broader question of which actives survive an oil only vehicle is worked through in menthol, camphor and actives.
Frequently asked questions
Does panthenol work in an oil based balm?
It can, but only if it is dispersed properly. Panthenol is practically insoluble in vegetable oils, so it has to be carried as fine droplets using a propanediol solution, a polyglyceryl emulsifier or a ready made oil dispersion. Stirred in neat it separates into a syrupy layer. At 0.5 to 1 percent in a base containing castor oil or lanolin it stays put and behaves.
What is the difference between D panthenol and DL panthenol?
D panthenol, also called dexpanthenol, is the single active enantiomer and a clear viscous liquid. DL panthenol is a racemic mixture, supplied as a white crystalline solid, and only half of it is the biologically active D form. Five percent DL panthenol therefore delivers 2.5 percent of active material, and the crystals bring a grit risk that the liquid does not.
How much panthenol should I use in a lip balm?
Between 0.5 and 1 percent for a twist tube, and up to 2 percent in a tin, with a carrier in both cases. Above that the exposed surface of the stick becomes permanently tacky because panthenol is strongly hygroscopic. The 5 percent figure people quote comes from medicinal dexpanthenol ointments built on petrolatum and lanolin, not from wax and oil sticks.
Why has my panthenol balm gone sticky on the surface?
Panthenol pulls water out of the air. Droplets that reach the surface stay wet, so the exposed face of a stick develops a tacky skin that collects lint. Nothing has degraded. The fixes are to lower the level, to disperse the panthenol more finely so less of it reaches the surface, or to switch to the oil soluble triester, which is not hygroscopic.
Is panthenyl triethylhexanoate as good as panthenol?
It solves the formulation problem and weakens the evidence. It is fully oil soluble and never separates, but it is only about 35 percent panthenol by mass and skin esterases have to cleave it before any panthenol is released. Three percent of the ester delivers at most the equivalent of one percent panthenol, and the clinical work behind the claims was done on dexpanthenol itself.
Does panthenol need a preservative in a balm?
The pure material does not, because a dry balm has no free water for microbes to use. The diluted grades are a different matter: panthenol 75W is a quarter water, so adding 4 percent of it puts 1 percent free water into the formula and the product is no longer anhydrous. Use the neat liquid or a glycol solution instead.
Can I add panthenol to a hot melt?
Add it off the heat at 60 to 65 C, once the base is fluid but no longer being heated. Panthenol is stable in a dry balm, and the hydrolysis that limits it in water cannot happen, but held above about 70 C it yellows and then browns permanently. Stir for a full minute, because the syrup is viscous enough to rope rather than disperse.
Sources and further reading
- European Directorate for the Quality of Medicines and HealthCare, European Pharmacopoeia monograph: Dexpanthenol, Strasbourg.
- United States Pharmacopeial Convention, USP-NF monograph: Dexpanthenol, Rockville MD.
- National Library of Medicine, PubChem compound summary: dexpanthenol, NCBI.
- Cosmetic Ingredient Review, Safety assessment of panthenol, pantothenic acid and related ingredients, Washington DC.
- Proksch E and Nissen HP, Dexpanthenol enhances skin barrier repair and reduces inflammation after sodium lauryl sulphate-induced irritation, Journal of Dermatological Treatment, 2002;13(4):173-178.
- Ebner F, Heller A, Rippke F and Tausch I, Topical use of dexpanthenol in skin disorders, American Journal of Clinical Dermatology, 2002;3(6):427-433.
- European Commission, CosIng cosmetic ingredient database, entries for Panthenol and Panthenyl Triethylhexanoate.
Reviewed and updated 6 September 2026. Spotted an error? Tell us and we will fix and log it.