Two things get said about hyaluronic acid more than anything else: that it holds 1,000 times its weight in water, and, usually offered as the catch, that in dry air it does the opposite of what you bought it for, pulling water out of your own skin because there is none in the room to pull from.
In our article on mineral oil we looked for a measurement of that second claim on human skin, did not find one, and promised to come back to it with hyaluronic acid. We followed both claims to the oldest sources we could read. One ends in a misunderstanding about what it means for a molecule to hold water; the other in two old glycerin experiments from one laboratory, on forearms in 1957 and in a dish in 1974, which found something real and disagreed about what it meant.
Table of contents
- Two variables decide the answer
- Where 1,000 times its weight comes from
- Holding water is not the same as binding it
- Where it dries you out comes from
- How much water a humectant can take from the air
- What has been measured on living skin
- Does molecular weight matter?
- The answer, case by case
- Verdict
- Where to find these
- References
We do not run a laboratory and we have tested nothing. Everything here comes from reading documents, all opened by us on 17 September 2026; the references say which we read in full and which only in abstract.
None of this is medical advice. If you have a skin condition, the people to ask are a dermatologist or a pharmacist.
Two variables decide the answer
A humectant attracts and holds water; glycerin is the classic one, hyaluronic acid the fashionable one. An occlusive, such as petrolatum or mineral oil, slows water leaving and attracts none. The mineral oil article sets the difference out.
In theory, the answer depends on how much water is in the air and whether anything sits on top to slow evaporation: four combinations, not all measured, and the measured ones measured in very different ways. The two claims first, then the combinations.
Where 1,000 times its weight comes from
The number is easy to find. Neutrogena’s guide to the ingredient says “Hyaluronic acid can hold up to 1,000 times its weight in water”, and links that sentence to a 2022 review in Dermatologic Therapy. The review says volume, not weight: hyaluronic acid has “the ability to bind 1000 times its volume in water”. L’Oréal funded the clinical study it reports, four of its five authors work for the company and the fifth is a paid consultant to it. CeraVe links its own ingredient page to the same review and says something far more modest: “hyaluronic acid can hold several times its weight in water”.
Of the three sources the review cites for that passage, the one we read, a 2012 review of hyaluronic acid in skin aging, contains no water-holding figure at all. A separate trail runs through a 2008 review in Veterinarni Medicina, which says the coil “traps approximately 1 000 times its weight in water” and cites a 2005 review by Cowman and Matsuoka. That review is paywalled; its abstract is about how the molecule behaves in solution, its “hydrodynamic properties”, with no water figure.
The US cosmetic safety panel carries a bigger number still: its 2023 safety assessment of hyaluronates says “1 g of Hyaluronic Acid can hold up to 6 l of water”, 6,000 times its weight, with no reference on the sentence.
The most detailed attempt to find the source that we came across is a 2024 paper by Scott Borchers and Michael Pirrung of the University of California, Riverside, which we read in full. They traced the six liters to a 1998 review by Sutherland, which they quote as saying the capacity “can be up to six litres of water per gram of polysaccharide”, and report that “data to support this statement are not found in this article, and neither is a citation to any literature that made such a measurement”. We could not read Sutherland. For the step down from 6,000 to 1,000 they found nothing: “Our review of this literature has not found a basis for this change”.
Holding water is not the same as binding it
Borchers and Pirrung offer a likely, not proven, explanation for the big numbers. In the 1950s and 1960s the biochemist A. G. Ogston measured how hyaluronic acid behaves in solution: a long, loose coil that drags a great deal of water along when it moves, enough to occupy about 6,000 milliliters per gram. “It seems quite likely that this particular report forms the basis” of the six liters, they write. But that water is not held in any chemical sense: “They move with the particle of HA and are neither bound to it by chemical forces nor trapped within it”. We have their account of Ogston, not Ogston’s papers.
They made a 0.1% solution of cosmetic-grade sodium hyaluronate, roughly 1,000 parts water to one part hyaluronic acid, and put it through two standard tests of how water freezes and evaporates. It behaved like plain water, “a free-flowing liquid that looks and behaves like water”; a 10% glycerin solution run alongside it did not. Their conclusion: “No experimental evidence was found for any special ability of hyaluronic acid to bind water at the claimed level of a thousand times by weight.”
They also summarize earlier studies of the water held tightly by the molecule, the water that no longer freezes normally: 0.36 to 0.86 grams per gram of hyaluronic acid. We have not read those studies; the range is theirs.
Under 1 g
Water held tightly per gram of hyaluronic acid in the studies Borchers and Pirrung summarize, against the 1,000 g in the claim
A National Science Foundation grant to the first author supported the paper, and we found no brand behind it. It is one paper and it measures nothing on skin; what it shows is that the famous number has nothing measured under it that anyone has put on the page.
Where it dries you out comes from
The second claim appears in clinical references too. StatPearls, on the National Library of Medicine’s bookshelf, says humectants “can hydrate the skin if the humidity is more than 70%; more commonly, however, they draw water from the deeper epidermis and dermis”. The L’Oréal-linked review says hyaluronic acid is classed as a humectant “since it draws water from the dermis to epidermis”. Neither sentence cites an experiment.
The oldest measurements we could read come from one company laboratory, Warner-Lambert in New Jersey. The later work is a pair of 1974 papers by Martin Rieger and Donald Deem; the second is the one that matters. They took sheets of stratum corneum, the skin’s outer layer, peeled from abdominal skin after death, mounted them in a cell with completely dry air outside, measured how fast water passed through, then applied an ingredient with a cotton swab and measured again.
| Applied to the skin sample | Rate of water passing through, compared with before |
|---|---|
| 25% glycerol | About twice as fast |
| 4% sodium PCA (a humectant) | About 1.6 times as fast |
| 4% sodium lactate (a humectant) | About 1.3 times as fast |
| Light mineral oil | About a quarter slower |
| Safflower oil | Slightly slower |
So in a dish, against completely dry air, humectants made water leave faster and oils slower. The authors’ summary: “The application of typical cosmetic humectants to the exposed side of the stratum corneum increases the rate of transepidermal water loss”. Hyaluronic acid was not tested. They warned that the results “obtained here are only directional”, since they could not measure how much of each ingredient stayed on.
Three things about this paper matter. First, it is not living skin: with no dermis behind the sample, it cannot show water being drawn up from the dermis. Second, the authors’ explanation is introduced with “Only a very tentative hypothesis is offered here” and has glycerin drawing water from the lower layers of the stratum corneum itself, not from deeper skin. Third, they thought this was how glycerin helps, by moving the point of evaporation from inside the outer layer up to its surface; for the help itself they had an unpublished company study of a glycerin preparation with nothing occlusive in it, and said plainly that “Published controlled clinical data attesting to the utility of humectants are missing”.
They were not the first, and the first test was not in a dish. They cite a 1957 conference paper by Donald Powers and Charles Fox of the same institute, and for the worry a 1973 trade magazine article by Chudzikowski; we could read neither, but Powers and Fox reprinted their data in a 1959 paper in the same journal, which we did. Cups of silica gel, a drying agent, were strapped to volunteers’ forearms for two hours, over bare skin and over an ingredient. Petrolatum cut the water collected by 48% and mineral oil by 28%; anhydrous glycerin raised it by 43%, and eleven of 21 shop-bought creams and lotions raised it too. So the oldest test we could read was on living skin and points the same way as the dish; it did not test hyaluronic acid either, and its authors wrote that “A great deal of additional study and work will be needed before any clear-cut conclusions can be drawn”.
At ordinary room humidity, a later forearm study found the opposite. In 1988, researchers at Beecham Products in England applied 5% and 15% glycerol in water to the inner forearms of young adults, six to eight volunteers per test, in rooms kept no warmer than 20 degrees Celsius and no more humid than 60% to limit sweating. Both solutions lowered water loss compared with plain water from ten minutes after application, and an oil-in-water cream with 10% glycerol lowered it against the same cream without glycerol for seven hours. The authors say their result “contradicts that published data (19,20) which was obtained either in vitro, where normal TEWL is lacking, or under conditions of abnormally low or zero external relative humidity”; their references 19 and 20 are the 1974 dish paper and the 1959 forearm paper. None of the three tested hyaluronic acid.
How much water a humectant can take from the air
The same paper measured how much water glycerin takes up at different humidities, which is why dry air matters. Dried glycerin was left at a set humidity until its weight stopped changing.
240%
Glycerin at 90% humidity
Water taken up, as a share of its own weight.
11%
Glycerin at 31% humidity
Same test, much drier air.
At 90% humidity glycerin took up more than twice its own weight in water; at 31%, about a tenth, around 22 times less; at 52%, 26%; at 76%, 67%. A humectant in dry air has much less water to draw on, the kernel of truth in the claim. Stratum corneum on its own took up 7% at 31%. Borchers and Pirrung cite a 1995 study of hyaluronic acid’s hydration against humidity, which we have not read.
What has been measured on living skin
Here the evidence gets thin, and three of the four studies below were run or paid for by companies in the beauty business. We found no study of hyaluronic acid on its own, on living human skin, in dry air, and none on people in which a hyaluronic acid product made skin drier or raised water loss. The closest we came:
- A hyaluronic acid gel in a Beijing winter. A 2025 study in Skin Research and Technology applied a gel with 0.5% of a hyaluronic acid combined with a plant polysaccharide to one side of the face of 24 volunteers and the same gel without it to the other. The base had no oil, silicone or glycerin; both sides carried 1% butylene glycol, another humectant. Volunteers spent half an hour outdoors, at minus 10 to minus 2 degrees Celsius and 16 to 23% humidity, then two hours indoors, twice. It reports hydration significantly higher on the treated side across five hours, and scales on the base side within half an hour. It is not plain hyaluronic acid, and three of the four authors work for a Beijing beauty company; the paper states “The authors received no specific funding for this work.”
- A serum measured in a dry room. A 2017 study of 20 women applied a fluid with 1% hyaluronic acid, 5% glycerin, a plant extract and caprylic glycerides to one forearm and left the other untreated. Hydration was higher and water loss lower on the treated arm 24 hours later. Readings were taken in a room at 30% humidity after 40 minutes to settle, and the paper does not say where the women were in between: a measuring standard, not a dry-air test. Difa Cooper, which sells the product, paid: “This study was supported by Difa Cooper SpA.” The first author is its medical director.
- A serum on its own, and with a cream. A 2026 study of 123 volunteers run by the skincare company Good Molecules compared a cleanser alone, a hyaluronic acid serum, a moisturizing cream, and the serum followed by the cream. At 30 minutes all three raised hydration over the cleanser; at eight hours, “only the Routine remained higher than FC”, the serum under the cream, though the serum alone still showed lower water loss. Neither the humidity nor the cream’s ingredients are in the abstract, all we could read.
- Sixty days of creams. In a 2011 study of 76 women, each applied a cream with 0.1% hyaluronic acid of one of five molecular sizes around one eye and the same cream without it around the other. All five improved skin hydration and elasticity compared with the plain cream. Abstract only; no humidity stated.
The animal evidence points the same way: in a 1998 study discussed in the mineral oil article, a humectant protected mice in very dry air from the skin changes it caused, as petrolatum and a plastic film did. A 2002 study from the same center shows what dry air does by itself: mice moved from humid to very dry air showed “a 6-7-fold increase in transepidermal water loss” that returned to normal within a week.
None of these tests the popular claim cleanly for hyaluronic acid, but in the one test of a hyaluronic acid product on people in genuinely dry air, with a complex rather than the plain ingredient, the opposite of what it predicts happened.
Does molecular weight matter?
Some hyaluronic acid serums advertise several sizes of the molecule, on the idea that smaller pieces get further into the skin. There is some evidence for it, most of it thin.
- A 2016 study used Raman spectroscopy on sections of human skin and reported that hyaluronic acid of 20 to 300 kilodaltons “passes through the stratum corneum in contrast of the impermeability of high molecular weight HA (1000-1400 kDa)”. One author works for an ingredient supplier; abstract only, so we could not read how the skin was prepared.
- The 2011 cream study above found that only the two smallest sizes, 50 and 130 kilodaltons, reduced wrinkle depth, and suggested this “may be due to better penetration abilities of LMW HA”, a guess rather than a measurement.
- A 2019 study of a micronized form measured penetration on pig skin, not human, and was sponsored by Hava Zingboim Ltd.
None of these measured whether smaller hyaluronic acid changes what happens in dry air, and the labels will not settle it. The Ordinary describes its serum as containing “5 types of hyaluronic acid”, but its ingredient list names three, with one entry for sodium hyaluronate, presumably where the three sizes sit. CeraVe’s serum lists glycerin second and sodium hyaluronate sixth. Our guide to ingredient lists explains what that order can and cannot tell you.
The answer, case by case
| Situation | What we found | What kind of evidence |
|---|---|---|
| Normal indoor air, nothing on top | Serums raised hydration for 30 minutes in one study, 24 hours in another. Glycerin in water lowered water loss | Two company studies of serums, humidity 30% or not given; one 1988 company forearm study of glycerin |
| Dry air, nothing on top | Humectants made water leave faster in a dish and under drying cups. One hyaluronic acid complex kept skin hydrated in winter air | A 1957 forearm test and a 1974 dish test, not of hyaluronic acid; one company study of a complex |
| Normal indoor air, a moisturizer on top | A serum under a cream held hydration for eight hours, longer than either alone | One company study; humidity and cream ingredients not given |
| Dry air, a moisturizer or occlusive on top | Not measured for hyaluronic acid. In a dish, mineral oil slowed water loss | One 1974 dish test of an oil alone |
So the careful version of the popular claim is this: in very dry air a humectant has little water to take from the air, and in a dish and under drying cups that raised water loss through the skin’s outer layer. At ordinary room humidity, glycerin on forearms lowered it. The claim that it pulls water from the dermis goes further than any experiment we read.
Verdict
Verdict
It does not hold 1,000 times its weight, and nobody has shown it dries out living skin
The 1,000 times figure has no measurement behind it that we could find; the studies of water held tightly by hyaluronic acid, as one careful paper summarizes them, found less than its own weight, and the large numbers appear to come from how much water a dissolved molecule drags around in solution. The idea that humectants pull water out of skin in dry air goes back, as far as we could read, to two tests of glycerin, on forearms under drying cups in 1957 and on isolated skin in a dish in 1974, neither of hyaluronic acid; at ordinary humidity, a 1988 forearm study found glycerin lowered water loss. On living skin, the studies we found, mostly company-run, show hyaluronic acid products improving hydration, one in winter air, and a cream on top made the effect last longer in the one study that tested it.
- 1,000 times its weight: no measurement found.
- Water tightly bound: under its own weight.
- Dries skin in dry air: seen with glycerin, in a dish and under a drying cup.
- Hyaluronic acid on people: not shown; one test found the reverse.
- Serum under a cream: longer-lasting in one study.
Where to find these
The links below are affiliate links; the disclosure above the article applies to all three. The first two are hyaluronic acid serums sold as cosmetics, both listing other humectants too; the third is a petrolatum jelly sold as an over-the-counter skin protectant, an occlusive, which our mineral oil article covers. None has been tested by us, and none of the studies above tested these products.
- CeraVe Hydrating Hyaluronic Acid Serum (paid link)
- The Ordinary Hyaluronic Acid 2% + B5 (with Ceramides) (paid link)
- Vaseline Original Healing Jelly (paid link)
For another ingredient, our article on azelaic acid found a similar gap between a popular concentration and the trials behind it.
We could not find one. Studies of the water held tightly by hyaluronic acid found less than its own weight; the large numbers appear to come from how much water a dissolved molecule drags along in solution, which is not holding it, and a 2024 study found a 0.1 percent solution behaved like plain water.
Nobody we could find has shown it on living skin. Tests from 1957 and 1974 found glycerin raised water loss in dry conditions but never tested hyaluronic acid, and in a 2025 study on people in winter air a gel of hyaluronic acid combined with a plant polysaccharide kept skin better hydrated than the same gel without it.
In the one study that compared them, company-run and with no humidity given, a hyaluronic acid serum followed by a cream kept hydration up for eight hours, longer than either alone. Oils slowed water loss in the 1957 and 1974 tests, but nobody we found has tested an occlusive over hyaluronic acid on people.
One study on human skin sections reported that hyaluronic acid of 20 to 300 kilodaltons passed the outer layer and larger molecules did not, and a cream study found only the smallest sizes reduced wrinkle depth. Both are small; neither measured dry air.
We found more measurements of glycerin than of hyaluronic acid, including how much water it takes up at different humidities, but no study comparing the two on skin head to head, so we cannot say one works better.
References
- Borchers S, Pirrung MC. The Fallacy of Hyaluronic Acid Binding a Thousand Times its Weight in Water. Journal of Cosmetic Science 2024;75(1):37-48. SCC library. Read in full.
- Rieger MM, Deem DE. Skin Moisturizers. II. The Effects of Cosmetic Ingredients on Human Stratum Corneum. Journal of the Society of Cosmetic Chemists 1974;25:253-262. SCC library. Read in full.
- Powers DH, Fox C. The Effect of Cosmetic Emulsions on the Stratum Corneum. Journal of the Society of Cosmetic Chemists 1959;10:109-116. SCC library. Read in full. Its Table 1 reproduces data first presented in Proceedings of the Scientific Section of the Toilet Goods Association 1957;28:21, which we could not read.
- Batt MD, Davis WB, Fairhurst E, Gerrard WA, Ridge BD. Changes in the physical properties of the stratum corneum following treatment with glycerol. Journal of the Society of Cosmetic Chemists 1988;39:367-381. SCC library. Read in full. Beecham Products Research Department.
- Bravo B, Correia P, Gonçalves Junior JE, Sant’Anna B, Kerob D. Benefits of topical hyaluronic acid for skin quality and signs of skin aging: From literature review to clinical evidence. Dermatologic Therapy 2022;35(12):e15903. PMC. Read in full. L’Oréal funded the study it reports; four authors are L’Oréal employees.
- Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: A key molecule in skin aging. Dermato-Endocrinology 2012;4(3):253-258. PMC. Read in full.
- Necas J, Bartosikova L, Brauner P, Kolar J. Hyaluronic acid (hyaluronan): a review. Veterinarni Medicina 2008;53(8):397-411. Journal PDF. Read in full.
- Cowman MK, Matsuoka S. Experimental approaches to hyaluronan structure. Carbohydrate Research 2005;340(5):791-809. Europe PMC. Abstract read.
- Cosmetic Ingredient Review. Safety Assessment of Hyaluronates as Used in Cosmetics. Final report, released 7 July 2023. cir-safety.org. Relevant section read.
- Harwood A, Nassereddin A, Krishnamurthy K. Moisturizers. StatPearls. NCBI Bookshelf. Read in full.
- Ren H, Di T, Meng H, Zha P. Supramolecular Assembly of Dendrobium officinale Polysaccharides-Hyaluronic Acid and Its Moisturizing Properties. Skin Research and Technology 2025;31(6):e70190. PMC. Read in full.
- Milani M, Sparavigna A. The 24-hour skin hydration and barrier function effects of a hyaluronic 1%, glycerin 5%, and Centella asiatica stem cells extract moisturizing fluid: an intra-subject, randomized, assessor-blinded study. Clinical, Cosmetic and Investigational Dermatology 2017;10:311-315. PMC. Read in full. Supported by Difa Cooper.
- Maldonado López AM, da Silva Souza ID. A serum and cream moisturization regimen outperforms separate use in sustaining hydration, reducing TEWL, and balancing surface lipids over an 8-h study. International Journal of Cosmetic Science 2026. Europe PMC. Abstract read.
- Pavicic T, Gauglitz GG, Lersch P, et al. Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment. Journal of Drugs in Dermatology 2011;10(9):990-1000. Europe PMC. Abstract read.
- Essendoubi M, Gobinet C, Reynaud R, et al. Human skin penetration of hyaluronic acid of different molecular weights as probed by Raman spectroscopy. Skin Research and Technology 2016;22(1):55-62. Europe PMC. Abstract read.
- Lubart R, Yariv I, Fixler D, Lipovsky A. Topical Hyaluronic Acid Facial Cream with New Micronized Molecule Technology Effectively Penetrates and Improves Facial Skin Quality. Journal of Clinical and Aesthetic Dermatology 2019;12(10):39-44. Europe PMC. Abstract read.
- Lodén M, Wessman W. The influence of a cream containing 20% glycerin and its vehicle on skin barrier properties. International Journal of Cosmetic Science 2001;23(2):115-119. Wiley. Abstract read; paywalled.
- Denda M, Sato J, Tsuchiya T, Elias PM, Feingold KR. Low humidity stimulates epidermal DNA synthesis and amplifies the hyperproliferative response to barrier disruption. Journal of Investigative Dermatology 1998;111(5):873-878. Europe PMC. Abstract read.
- Sato J, Denda M, Chang S, Elias PM, Feingold KR. Abrupt decreases in environmental humidity induce abnormalities in permeability barrier homeostasis. Journal of Investigative Dermatology 2002;119(4):900-904. Europe PMC. Abstract read.
- Brand pages read 17 September 2026: Neutrogena, CeraVe ingredient guide, CeraVe Hydrating Hyaluronic Acid Serum, The Ordinary Hyaluronic Acid 2% + B5.