Verified Beauty Data

Ingredient dossier Nº 006 / The verified record

Hyaluronic Acid

HYALURONIC ACID · CosIng 6550 · also Sodium Hyaluronate, Hydrolyzed Hyaluronic Acid, Hyaluronan, Sodium Hyaluronate Crosspolymer, Nano Hyaluronic Acid

Effective concentration, the pH it needs, how the derivatives compare, stability in the bottle, and the open questions — every scientific claim on this page links to its source.

Editorial verdict / Social intelligence

Qualified yes Ingredient dossier

A genuinely excellent humectant that outperforms its anti-aging marketing — essential for hydration, less essential if you're in a dry climate and skip the moisturizer. 1

Beauty benefit
The gold-standard humectant for skin hydration — draws water into the stratum corneum, temporarily plumps fine lines caused by dryness, and improves skin softness and elasticity. Works at the skin surface and upper epidermis; it does not replenish the body's deeper dermal HA stores. The benefit is real, immediate, and well-documented, but it is fundamentally a hydration story, not a structural anti-aging one.
Does it work
Yes, as a humectant — with important caveats. Multiple RCTs confirm measurable improvements in skin hydration, elasticity, and reduction in the appearance of dehydration fine lines at concentrations as low as 0.1% (Pavicic et al. 2011, PMID:22052267). A 2025 PMC review (PMC12731180) confirms clinical evidence for moisture, elasticity, and visible wrinkle reduction. However, topical HA does not replenish your skin's natural HA stores — it cannot meaningfully reach the dermis. High-MW HA stays on the surface; low-MW penetrates only into the epidermis. The 'anti-aging' marketing claim overstates the mechanism: HA reduces the look of fine lines caused by dryness, which reverses when you stop using it. In low-humidity environments (below ~40% RH), HA can paradoxically draw moisture from deeper skin layers and worsen dryness — this is a well-described humectant behavior, not a rare edge case. The fix: apply to damp skin and always seal with an occlusive or moisturizer. See the science below →

Consensus strength

Strong

Strong consensus on humectant efficacy: multiple RCTs, a 2025 PMC review, CIR safety approval, and consistent dermatologist endorsement confirm HA works as a hydration ingredient. Moderate consensus on the dry-climate draw-out caveat — it is widely acknowledged by dermatologists (Dr. Ava Shamban, multiple editorial sources) and supported by the ex vivo TEWL data (PMID:27050698 showing LMW HA increased TEWL by 55.5%). Strong consensus that topical HA does not replenish dermal HA stores (LabMuffin, PMC review, penetration science). Mixed on marketing framing: the beauty industry routinely positions HA as an 'anti-aging' ingredient; dermatologists and cosmetic chemists consistently correct this to a hydration/appearance story. No safety controversy — CIR 2009 and 2023 updates confirm safe as used.

01 / What it does

What it does

Hyaluronic acid (HA) is a naturally occurring, non-sulfated glycosaminoglycan found in the extracellular matrix of connective tissue, synovial fluid, and the dermis. Its defining property is hygroscopicity: it can bind up to 1,000 times its own weight in water, making it among the most potent humectants used in cosmetics. In skin, endogenous HA holds dermal water content, maintains tissue turgor and viscoelasticity, and participates in wound healing and inflammation regulation. As a topical ingredient, it primarily acts as a humectant that draws water into the stratum corneum and superficial epidermis, improving short-term skin hydration, plumping fine lines, and enhancing skin elasticity. Its effects are molecular-weight-dependent: high-molecular-weight forms create a surface film that reduces transepidermal water loss (TEWL), while low-molecular-weight and hydrolyzed forms penetrate more deeply but come with a complexity around pro-inflammatory potential at very small fragment sizes.

02 / Effective concentration

What percentage actually works

Effective range

0.1-2%

Cosmetic products typically use 0.1-2% HA or sodium hyaluronate. Higher concentrations do not improve efficacy and may produce a sticky, filming texture. The 0.1% concentration was the benchmark tested in the seminal Pavicic et al. (2011) multi-molecular-weight RCT.

Clinical evidence supports efficacy at 0.1% across all molecular weights in the Pavicic et al. 2011 RCT (n=76). The CIR Expert Panel noted concentrations up to 2% in cosmetic use. There is no established dose-response ceiling equivalent to the vitamin C saturation model; HA does not accumulate in skin tissue in the same way. Formulation texture and product feel typically limit concentrations to under 2% in serums and creams. Very high concentrations produce thick, gel-like textures requiring humectant-plus-occlusive strategy to avoid drawing moisture from deeper skin layers in dry conditions.

  • CIR Hyaluronic acid and its salts are used in cosmetics at concentrations up to 2%; the CIR Expert Panel found these concentrations safe for use in present practices. 11
  • Source 0.1% sodium hyaluronate formulations across all five molecular weights (50-2000 kDa) demonstrated significant skin hydration and elasticity improvements in a 60-day RCT (n=76 women). 1

One honest caveat Penetration data for topical HA are primarily from ex vivo skin models (excised human or porcine skin). In vivo confocal Raman studies are limited. Whether the penetration profiles translate directly to living human skin with active physiological processes is not definitively established.

03 / pH requirement

The pH it needs

Target pH

3.0-7.0 (stable across broad range)

Hyaluronic acid and sodium hyaluronate are stable across a much broader pH range than vitamin C derivatives, with functional stability typically reported from pH 3 to 7. Unlike L-ascorbic acid, HA does not require a low pH for skin activity — it functions as a humectant regardless of formulation pH. Extreme alkalinity (pH > 8) or strong acidity accelerates hydrolytic degradation of the glycosidic bonds. Standard cosmetic formulation pH of 4.5–6.5 provides optimal stability.

  • Review Unlike ionizable actives such as vitamin C, hyaluronic acid functions as a humectant across a broad cosmetic pH range and does not require a specific pH window for percutaneous activity. 5

04 / Derivative ladder

How the derivatives compare

Every derivative trades a measure of proven activity for stability or gentleness. Skin conversion is the question that matters — a more stable molecule only helps if your skin can turn it back into the active form.

  1. High-MW Hyaluronic Acid (>1000 kDa)

    HYALURONIC ACID

    At >1000 kDa, HA molecules are too large to penetrate intact stratum corneum. They remain on the skin surface and form a thin, viscoelastic, moisture-retaining film that: (1) limits transepidermal water loss via a semi-occlusive effect, (2) provides immediate tactile plumping and smoothness, and (3) acts as an anti-inflammatory via CD44 receptor interaction with intact chains. High-MW HA is the native form in dermis, where it contributes to tissue hydration and structural integrity. Raman spectroscopy data confirm impermeability of 1000-1400 kDa HA across intact stratum corneum.

    • Study Hyaluronic acid of 1000-1400 kDa molecular weight does not penetrate through the stratum corneum, as demonstrated by Raman micro-imaging of human skin ex vivo; low-MW HA (20-300 kDa) crossed the stratum corneum. 6
    • Review High molecular weight HA functions through CD44 receptor interaction to inhibit inflammatory cytokine production, reduce macrophage phagocytosis, and act as anti-inflammatory in contrast to pro-inflammatory low-MW fragments. 8

  2. Low-MW / Hydrolyzed Hyaluronic Acid (<300 kDa)

    HYDROLYZED HYALURONIC ACID

    Low-MW and hydrolyzed HA (20-300 kDa) penetrates the stratum corneum and reaches the epidermis, enabling deeper humectancy. However, it does not form the surface film of high-MW HA and provides less TEWL reduction. Critically, very small HA oligomers and fragments (<10 kDa) act as damage-associated molecular patterns (DAMPs) that activate Toll-like receptors (TLR2/TLR4), triggering pro-inflammatory cytokine release (IL-1β, TNF-α) — this is the relevant signal of tissue damage in vivo. The clinical significance of this mechanism for topically applied cosmetic low-MW HA is contested and not established by clinical evidence, but it represents the honest complexity around 'deeper-penetrating' forms.

    • Study Low molecular weight HA (20-300 kDa) penetrates through the stratum corneum while high MW HA (1000-1400 kDa) remains impermeant, as shown by Raman spectroscopy in human skin ex vivo. 6
    • Study Low MW HA (5 kDa) enhanced penetration of BSA into the epidermis in healthy human skin ex vivo, likely through increased hydration-mediated modification of stratum corneum properties. 7
    • Review Low MW HA fragments act as DAMPs, promoting dendritic cell activation and maturation and release of pro-inflammatory cytokines (IL-1β, TNF-α) via TLR2/TLR4 signaling, in contrast to the anti-inflammatory signaling of intact high-MW HA via CD44. 8

  3. Sodium Hyaluronate (salt form)

    SODIUM HYALURONATE

    Sodium hyaluronate is the sodium salt of hyaluronic acid and is the primary commercial form used in cosmetics, being more water-stable and less hygroscopic in dry powder form than free hyaluronic acid. At equivalent molecular weight, sodium hyaluronate and hyaluronic acid have functionally equivalent activity. It is the form evaluated in the CIR 2009 safety assessment and the majority of clinical trials. The salt designation in a product INCI list does not specify molecular weight — manufacturers use sodium hyaluronate across the full MW range from high to hydrolyzed.

    • CIR Sodium hyaluronate and hyaluronic acid were both assessed and found safe as cosmetic ingredients by the CIR Expert Panel at concentrations up to 2%; sodium hyaluronate is the predominant salt form in commercial formulations. 11

  4. Sodium Hyaluronate Crosspolymer

    SODIUM HYALURONATE CROSSPOLYMER

    Crosslinked forms of sodium hyaluronate are produced by chemical crosslinking of HA chains (BDDE or similar). They are larger, more viscous, and more resistant to hyaluronidase degradation than linear HA. Used topically, crosslinked HA forms a durable, film-forming humectant layer. In a comparative ex vivo study, crosslinked resilient HA (RHA) outperformed both HMW and LMW linear HA in reducing TEWL (-27.8% vs -15.6% for HMW and +55.5% for LMW) and improving epidermal water content. Primarily used in professional post-procedure skincare and high-end consumer serums.

    • Study Topical crosslinked resilient hyaluronic acid (RHA) reduced TEWL by 27.8% versus -15.6% for high-MW linear HA and +55.5% (increase) for low-MW linear HA in a dynamic 3D human explant model. 10

05 / Stability & storage

Stability in the bottle

Sodium hyaluronate (the sodium salt) is considerably more stable in formulation than free hyaluronic acid. HA is susceptible to enzymatic degradation by hyaluronidase in vivo and to chemical hydrolysis under extremes of pH, temperature, and free radical exposure. UV radiation and reactive oxygen species fragment native HA chains in skin over time, contributing to photoaging-associated dermal water loss. High-MW HA in solution is stable under typical cosmetic processing conditions. Hydrolyzed HA (low-MW, <50 kDa) produced by acid or enzymatic hydrolysis is inherently more stable as the chain length is already shortened. Crosslinked forms (sodium hyaluronate crosspolymer) are highly resistant to enzymatic degradation.

In practice Buy it in an opaque, airless, or amber container, store it cool and out of the light, and treat a colour shift toward orange or brown as the signal to replace it — the molecule is telling you it has already oxidised.

06 / How to use it

How to actually use Hyaluronic Acid

When
AM/PM — On damp skin, then seal with moisturizer.
Pairs well with
everything.
Apply apart from
Nothing major — it layers comfortably with most actives.
What to look for
A serum with multiple molecular weights.
Heads-up
In dry climates apply to damp skin and seal it in, or it can pull moisture from deeper skin.

Practical guidance for routine placement — not a substitute for a dermatologist’s advice for your skin.

07 / The database

Every Hyaluronic Acid product, cheapest active-gram first

Ranked by $ per gram of active — what the working ingredient actually costs you, not the sticker price. Rows we have reviewed in full link through; the rest are data points from the same crawl.

Buy The Ordinary on Amazon $9.90 Top-ranked pick · affiliate link

# Product % Price $ / g of active
1 The Ordinary Hyaluronic Acid 2% + B5 Hydrating Serum with Ceramides - Hydrating Serum 1.0 oz Reviewed in full 2% $9.90 $16.74
2 L'Oréal Revitalift 2.5% Hyaluronic Acid + Caffeine Under Eye Serum Ulta 2.5% $35.99 $72.65
3 Kiehl's Since 1851 Ultra Pure High-Potency 1.5% Hyaluronic Acid Serum Ulta 1.5% $40.00 $90.17

Showing the 3 lowest-cost of 3 measured .

Contains it, but doesn't disclose a percentage: SOME BY MIRetinol Intense Reactivating Mask ; ANUAKPop Demon Hunters 8 Hyaluronic Acid Catechin Cool Slim Mask ; ANUAKPop Demon Hunters Heartleaf 77 Soothing Mask ; ANUAKPop Demon Hunters Rice 70 Intensive Moisturizing Milk Mask ; TONYMOLYI Am Sheet Mask - Aloe ; EssenceSpot Squad Pimple Patches — and 14 more.

08 / Safety

Is it safe?

Reviewed by the Cosmetic Ingredient Review — safe as used

Safe as used — Final Report 2009 (PMID:19636067). The CIR Expert Panel reviewed hyaluronic acid, potassium hyaluronate, and sodium hyaluronate and concluded they are safe for cosmetic use at concentrations up to 2%. No sensitization, genotoxicity, reproductive toxicity, or carcinogenicity was identified across extensive animal and clinical datasets. The Panel noted that preparations derived from animal sources (rooster combs) require appropriate procedures to limit infectious agents and minimize biological impurities (DNA, endotoxins, proteins). Biotechnology-derived (bacterial fermentation) sodium hyaluronate avoids animal-sourced contamination concerns. A 2023 updated CIR Final Report on Hyaluronates (including hydrolyzed forms) confirmed the safety conclusion for the expanded ingredient group.

Topical HA has a favorable safety profile with no established skin sensitization. Very small HA oligomers theoretically activate TLR-mediated inflammation, but clinically significant inflammatory reactions from cosmetic topical HA have not been documented in the peer-reviewed literature. The primary formulation caveat is the potential for humectant-driven TEWL increase in very low-humidity environments without an occlusive co-ingredient. HA is not comedogenic and has no established photosensitizing activity.

  • CIR Hyaluronic acid, potassium hyaluronate, and sodium hyaluronate are safe as used in cosmetic formulations; no toxicity, sensitization, genotoxicity, developmental toxicity, or carcinogenicity was identified in a comprehensive CIR safety assessment. 11

09 / The limits of the evidence

What we don't know yet

Most of what you read about this ingredient is stated with more certainty than the evidence earns. Here is exactly where the record thins out — so you can weigh the claims above for yourself.

  1. Penetration data for topical HA are primarily from ex vivo skin models (excised human or porcine skin). In vivo confocal Raman studies are limited. Whether the penetration profiles translate directly to living human skin with active physiological processes is not definitively established.
  2. The pro-inflammatory DAMP effect of very low-MW HA oligomers (<10 kDa) is characterized in systemic and joint models; its clinical relevance in topically applied cosmetic low-MW HA at 0.1-2% concentrations has not been specifically studied in human RCTs.
  3. The low-humidity draw-out effect (humectants increasing TEWL in dry conditions) is well-characterized for humectants as a class and indirectly supported by the TEWL data in PMID:27050698, but a dedicated RCT measuring HA-specific TEWL increase under controlled low-humidity exposure in human subjects was not located in this review.
  4. Most HA topical RCTs do not compare against a non-humectant moisturizer control; it is difficult to separate the humectant hydration effect of HA from generic moisturizing effects of vehicle ingredients.
  5. Long-term comparative trials (>12 months) of different HA molecular weight formulations for anti-aging endpoints have not been published.
  6. Sodium hyaluronate crosspolymer safety and efficacy data are primarily from a single pilot explant study (PMID:27050698); independent clinical RCT replication is limited.
  7. CosIng direct reference number for hyaluronic acid and sodium hyaluronate could not be confirmed via automated database fetch; the CosIng entries at ec.europa.eu are the authoritative source (search 'hyaluronic acid' at https://ec.europa.eu/growth/tools-databases/cosing/).

10 / What people say

What formulators and users say

What works

  • Common Immediate, visible hydration boost — skin looks plumper, softer, and more radiant within days of consistent use 76
    The hydration factor is pretty immediate. In a matter of days, the skin will appear more radiant, feel softer and firmer — Dr. Ava Shamban Dermatologist
  • Common Clinical evidence supports reduction in the appearance of fine lines and wrinkles — driven by improved hydration, not structural remodeling 15
    All five HA molecular weights (50–2000 kDa) at 0.1% produced significant improvement in skin hydration and elasticity versus placebo at 60 days; lower MW (50 and 130 kDa) showed greater wrinkle depth reduction Study
  • Common Excellent safety and tolerability — universally well-tolerated across skin types, non-comedogenic, no established sensitization risk 48
    Hyaluronic acid, potassium hyaluronate, and sodium hyaluronate are safe as used in cosmetic formulations; no sensitization, genotoxicity, developmental toxicity, or carcinogenicity identified Study
  • Common Plays well with nearly every other skincare active — no interaction conflicts with retinoids, vitamin C, AHAs, or SPF 96
    sodium hyaluronate is typically smaller fragments; safe to layer with other actives as it functions as a humectant, not an active that conflicts chemically Editorial
  • Common Naturally occurring molecule the body already makes — soothing for sensitive and compromised skin, supports barrier recovery 514
    HA provides anti-inflammatory and healing properties as well as moisturizing effects; high-MW HA has anti-inflammatory activity via CD44 receptor interaction Study
  • Some Multi-MW formulations offer both surface plumping (high-MW film-forming) and deeper epidermal hydration (low-MW penetration) in a single product 26
    high-MW HA (1000–1400 kDa) does not penetrate the stratum corneum and remains at the surface; low-MW HA (20–300 kDa) crosses the stratum corneum — confirmed by Raman spectroscopy Study

What to know

  • Common In dry or cold climates (humidity below ~40%), HA can backfire — drawing moisture upward from deeper skin layers and leaving skin more dehydrated than before 71011
    in very dry climates, hyaluronic acid can work counterintuitively, pulling moisture from deeper layers of the dermis up to the surface and potentially leaving skin feeling more dehydrated — Dr. Ava Shamban Dermatologist
  • Common Pilling — too much HA serum, applied over incompatible products or before fully absorbing, balls up visibly on the skin 129
    Yes, too much hyaluronic acid can lead to pilling. Stick to recommended amounts and layer with compatible products. Editorial
  • Common Sticky, tacky finish — high-MW HA serums can leave a gummy, wet-feeling residue, especially if over-applied or used without sealing moisturizer 1211
    Flaking often occurs due to over-application or layering with incompatible products Editorial
  • Some Results are temporary and reversible — hydration plumping and fine-line softening disappear if you stop using it; HA does not structurally repair skin 98
    don't be fooled into thinking that applying hyaluronic acid on your skin can help replenish your natural stores! Even low molecular weight HA can only penetrate into the lower epidermis — Michelle Wong, LabMuffin Editorial
  • Some Oversold as 'anti-aging' — the marketing far outpaces the mechanism; HA does not rebuild collagen, restore volume, or reverse intrinsic aging 7513
    HA isn't an overnight miracle despite its popularity; significant changes in firmness and fine lines can take two to three months of consistent usage — Dr. Ava Shamban Dermatologist

What you'd only know from the reviews

  • Apply HA to damp — not dry — skin, then immediately seal with a cream or occlusive. This single technique change is the most commonly missed step and the root cause of the 'HA dried out my skin' complaint. The humectant needs ambient or surface moisture to grab onto; applied to bone-dry skin in a dry room, it grabs from below instead. 7108

  • The MW label on a product tells you almost nothing useful. 'Sodium hyaluronate' on an INCI list does not specify molecular weight — it could be high, low, or hydrolyzed. The meaningful distinction (surface-film vs. penetrating) requires the brand to disclose actual MW ranges, which most do not. Multi-MW formulas are rationally motivated but frequently used as marketing rather than a disclosed technical spec. 92

  • Low-MW HA can actually increase TEWL (transepidermal water loss) — the ex vivo crosslinked HA study showed LMW linear HA raised TEWL by 55.5% vs. baseline, while high-MW and crosslinked forms reduced it. This confirms the molecular weight and formulation architecture determine whether HA helps or hurts your skin barrier, not the HA label alone. 3

  • HA's reputation as a 'skin replenisher' is biologically backwards — topical application cannot restore the body's own HA in the dermis. Even the best-penetrating low-MW forms reach only the lower epidermis, not the dermis where native HA lives. The ingredient is doing something real and useful, just not what most marketing implies. 95

  • If you live in a desert, high-altitude, or centrally-heated winter environment, you may genuinely get more hydration from an oil like squalane than from an HA serum alone. At humidity below 30%, polyglutamic acid (a larger humectant that sits at the surface and draws from air more efficiently than HA) or a pure occlusive may outperform standalone HA altogether. 1113

  1. 1 Study Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment — PubMed PMID:22052267 2011
  2. 2 Study Human skin penetration of hyaluronic acid of different molecular weights as probed by Raman spectroscopy — PubMed PMID:25877232 2016
  3. 3 Study Pilot Comparative Study of Topical Crosslinked Resilient Hyaluronic Acid on Skin Hydration and Barrier Function — PubMed PMID:27050698 2016
  4. 4 Study Final Report of the Safety Assessment of Hyaluronic Acid, Potassium Hyaluronate, and Sodium Hyaluronate — PubMed PMID:19636067 (CIR 2009) 2009
  5. 5 Study Hyaluronic Acid in Topical Applications: The Various Forms and Biological Effects of a Hero Molecule in the Cosmetics Industry — PMC12731180 2025
  6. 6 Study Clinical Evaluation of Next-generation, Multi-weight Hyaluronic Acid Plus Antioxidant Complex Topical Formulations — JCAD 2024
  7. 7 Dermatologist How to use hyaluronic acid: A dermatologist gives us the lowdown on what it really does — Yahoo Shopping (Dr. Ava Shamban) 2024
  8. 8 Dermatologist Dermatologist-Recommended Hyaluronic Acid Serum: Top Choices — DermOnDemand 2024
  9. 9 Editorial What is hyaluronic acid and how does it work in skincare and makeup? — Lab Muffin Beauty Science (Michelle Wong) 2025
  10. 10 Editorial Can Hyaluronic Acid Dry Your Skin? — Timeless Skin Care 2024
  11. 11 Editorial How to Maximize Hyaluronic Acid in Dry Climate Conditions — Smytten Blog 2024
  12. 12 Editorial How to Prevent and Solve for Product Pilling — The Ordinary 2024
  13. 13 Editorial Hyaluronic Acid Serum Skin Dry Fail: Medical Next Steps — Ubie Health Doctor's Note 2024
  14. 14 Editorial Hyaluronic Acid: A Winter Essential for Healthy, Hydrated Skin — Dermatology Columbus 2024

11 / Questions

Frequently asked

What does hyaluronic acid do for skin?
Hyaluronic acid functions primarily as a humectant — it draws and binds water into the stratum corneum and superficial epidermis, improving skin hydration, reducing the appearance of fine lines caused by dryness, and contributing to improved skin elasticity. In the Pavicic et al. 2011 RCT (n=76, PMID:22052267), all HA molecular weights tested at 0.1% significantly improved skin hydration and elasticity versus placebo after 60 days. Endogenously, HA is a structural component of the dermis that maintains tissue turgor and participates in wound healing, but topically applied HA primarily exerts its benefit at the skin surface and upper epidermis, not deep in the dermis. 15
Does hyaluronic acid actually penetrate skin?
It depends entirely on molecular weight. Raman spectroscopy data (Essendoubi et al. 2016, PMID:25877232) demonstrated that high-MW HA (1000-1400 kDa) does not cross intact stratum corneum and remains on the surface. Low-MW HA (20-300 kDa) does penetrate the stratum corneum. However, penetrating the stratum corneum is not the same as reaching the dermis — even low-MW HA reaches only the superficial epidermis. Claims that topically applied HA 'replenishes' or 'reaches' the dermis are not supported by current penetration data. The surface film formed by high-MW HA still provides meaningful hydration benefit via reduced TEWL and atmospheric moisture trapping. 67
High vs low molecular weight hyaluronic acid — which is better?
Neither is universally superior; they exert different mechanisms. High-MW HA (>1000 kDa) forms a surface film, reduces TEWL, provides immediate plumping, and has anti-inflammatory properties via CD44. Low-MW HA (<300 kDa) penetrates the stratum corneum and may hydrate deeper epidermal layers. The Pavicic et al. 2011 RCT (PMID:22052267) showed that lower MW forms (50 and 130 kDa) produced better wrinkle depth reduction, suggesting deeper penetration may contribute incrementally to anti-wrinkle effects. However, very small HA fragments (<10 kDa) can activate pro-inflammatory TLR2/TLR4 signaling (PMID:35369538) — the clinical relevance for cosmetic formulations is not established, but it is a biological caveat worth naming. Multi-MW formulations are rationally motivated by combining surface-film and penetrating hydration mechanisms. 168
Can hyaluronic acid dry out your skin?
In low-humidity environments, yes — this is a well-described humectant behavior. Humectants draw water from wherever it is most available: the atmosphere when ambient humidity is above ~70%, and from deeper epidermal and dermal layers when humidity is lower (Harwood et al., StatPearls NBK545171). When HA draws water upward from the dermis and stratum corneum, and that water then evaporates from the skin surface without an occlusive barrier, net skin dryness can result. This is why humectants are often recommended in combination with occlusive moisturizers in dry or cold weather conditions. The crosslinked RHA comparative study (PMID:27050698) importantly demonstrated that low-MW linear HA increased TEWL by 55.5% versus baseline in an ex vivo model, while crosslinked and high-MW forms reduced TEWL — confirming that molecular weight and formulation architecture are critical to whether HA helps or worsens skin barrier function. 10
What is the difference between hyaluronic acid and sodium hyaluronate?
Hyaluronic acid is the free acid form; sodium hyaluronate is its sodium salt (the Na+ replaces the acidic proton on the carboxylate group). In practice, both are the same molecule at equivalent molecular weight and have the same biological activity. Sodium hyaluronate is more stable in formulation, less hygroscopic as a dry ingredient, and dissolves more readily in water — which is why it dominates commercial cosmetic production. The INCI name 'Sodium Hyaluronate' on a product label does not tell you the molecular weight; it could be high, low, or hydrolyzed. The salt vs. free acid distinction matters for formulation chemistry but is not a meaningful factor in consumer skin benefit decisions. 115

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More from the verified record

12 / References

Sources

13 references · verified 2026-06-12
  1. 1

    Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment

    Pavicic T, Gauglitz GG, Lersch P, Schwach-Abdellaoui K, Malle B, Korting HC, Farwick M · Journal of Drugs in Dermatology 10(9):990-1000 · 2011

  2. 2

    Efficacy of a New Topical Nano-hyaluronic Acid in Humans

    Jegasothy SM, Zabolotniaia V, Bielfeldt S · The Journal of Clinical and Aesthetic Dermatology 7(3):27-29 · 2014

  3. 3

    Benefits of topical hyaluronic acid for skin quality and signs of skin aging: From literature review to clinical evidence

    Bravo B, Correia P, Gonçalves Junior JE, Sant'Anna B, Kerob D · Dermatologic Therapy 35(12):e15903 · 2022

  4. 4

    Anti-aging and filling efficacy of six types hyaluronic acid based dermo-cosmetic treatment: double blind, randomized clinical trial of efficacy and safety

    Nobile V, Buonocore D, Michelotti A, Marzatico F · Journal of Cosmetic Dermatology 13(4):277-87 · 2014

  5. 5

    Hyaluronic acid, a promising skin rejuvenating biomedicine: A review of recent updates and pre-clinical and clinical investigations on cosmetic and nutricosmetic effects

    Bukhari SNA, Roswandi NL, Waqas M, Habib H, Hussain F, Khan S, Sohail M, Ramli NA, Thu HE, Hussain Z · International Journal of Biological Macromolecules 120(Pt B):1682-1695 · 2018

  6. 6

    Human skin penetration of hyaluronic acid of different molecular weights as probed by Raman spectroscopy

    Essendoubi M, Gobinet C, Reynaud R, Angiboust JF, Manfait M, Piot O · Skin Research and Technology 22(1):55-62 · 2016

  7. 7

    Interactions of hyaluronic Acid with the skin and implications for the dermal delivery of biomacromolecules

    Witting M, Boreham A, Brodwolf R, Vávrová K, Alexiev U, Friess W, Hedtrich S · Molecular Pharmaceutics 12(5):1391-401 · 2015

  8. 8

    Action of Hyaluronic Acid as a Damage-Associated Molecular Pattern Molecule and Its Function on the Treatment of Temporomandibular Disorders

    Ferreira NDR, Sanz CK, Raybolt A, Pereira CM, DosSantos MF · Frontiers in Pain Research (Lausanne) 3:852249 · 2022

  9. 9

    Anti-inflammatory effects of differential molecular weight Hyaluronic acids on UVB-induced calprotectin-mediated keratinocyte inflammation

    Hu L, Nomura S, Sato Y, Takagi K, Ishii T, Honma Y, Watanabe K, Mizukami Y, Muto J · Journal of Dermatological Science 107(1):24-31 · 2022

  10. 10

    Pilot Comparative Study of the Topical Action of a Novel, Crosslinked Resilient Hyaluronic Acid on Skin Hydration and Barrier Function in a Dynamic, Three-Dimensional Human Explant Model

    Sundaram H, Mackiewicz N, Burton E, Peno-Mazzarino L, Lati E, Meunier S · Journal of Drugs in Dermatology 15(4):434-41 · 2016

  11. 11

    Final report of the safety assessment of hyaluronic acid, potassium hyaluronate, and sodium hyaluronate

    Becker LC, Bergfeld WF, Belsito DV, Klaassen CD, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW; Cosmetic Ingredient Review Expert Panel; Andersen FA · International Journal of Toxicology 28(4 Suppl):5-67 · 2009

  12. 12

    Moisturizers (StatPearls)

    Harwood A, Nassereddin A, Krishnamurthy K · StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing · 2023

  13. 13

    Safety Assessment of Hyaluronates as Used in Cosmetics — Final Report

    Cosmetic Ingredient Review Expert Panel · Cosmetic Ingredient Review · 2023