Hyaluronic acid applied to skin or taken as a supplement does not cause cancer cells to grow. The relationship between hyaluronic acid (HA) and cancer is real but far more nuanced than a simple cause-and-effect story. Inside the body, HA exists in different sizes, and the size of the molecule determines whether it behaves protectively or harmfully. What happens in a tumor’s local environment with fragmented, small HA molecules is fundamentally different from what happens when you apply a serum or swallow a capsule, and conflating the two has become a persistent source of anxiety that the science does not support.
Why Size Is the Whole Story
HA is a naturally occurring sugar chain found throughout the body, concentrated in skin, joints, and connective tissue. Your body produces it constantly. The crucial detail that gets lost in headlines is that HA molecules come in vastly different sizes, and those sizes have opposite biological effects. High-molecular-weight HA, the kind your healthy tissues maintain, supports normal cell behavior and tissue integrity. Low-molecular-weight HA, the kind generated when enzymes chop large HA into fragments, sends very different signals to cells and has been linked to inflammation and tumor-promoting activity.1PubMed Central. Hyaluronic Acid as a Modern Approach in Anticancer Therapy-Review
This dual nature is not a minor footnote. A 2024 review described HA’s role as genuinely two-faced: low-molecular-weight HA and the genes that break HA down play a significant role in establishing the tumor microenvironment by helping cancer cells proliferate, spread, and invade surrounding tissue. Meanwhile, high-molecular-weight HA serves as a platform for targeted cancer drug delivery and exerts anti-inflammatory properties.2PubMed. Hyaluronic acid as a tumor progression agent and a potential chemotherapeutic biomolecule against cancer: A review on its dual role So the question “does HA cause cancer to grow” is a bit like asking “does water help fires” without specifying whether you mean pouring it on flames or using steam to power a turbine. The molecule is the same. The context and form are everything.
What the Naked Mole-Rat Teaches Us
One of the most striking pieces of evidence for high-molecular-weight HA being cancer-protective comes from an unusual animal. Naked mole-rats are famously resistant to cancer, and researchers discovered that their cells produce HA molecules more than five times larger than those made by human or mouse cells. This oversized HA accumulates in their tissues because the enzymes that would normally break it down are less active. When researchers removed this high-molecular-weight HA from naked mole-rat cells, either by silencing the gene that produces it or by overexpressing the enzyme that degrades it, the cells suddenly became vulnerable to cancerous transformation and readily formed tumors when implanted in mice.3PubMed Central. High-molecular-mass hyaluronan mediates the cancer resistance of the naked mole rat
Separately, research has shown that the high-molecular-weight HA found in the spaces between cells can trigger a pathway that activates a known tumor suppressor, effectively putting the brakes on cancerous changes.4PubMed Central. Cancer resistance, high molecular weight hyaluronic acid, and longevity This is the opposite of causing cancer. High-molecular-weight HA actively suppresses it, at least in certain biological contexts. The naked mole-rat story is not proof that rubbing HA on your face prevents cancer, but it powerfully illustrates that HA’s size determines its biological meaning.
How Tumors Hijack HA for Their Own Purposes
If large HA is protective, the problem begins when tumors break it apart. Many cancer cells ramp up production of enzymes called hyaluronidases that degrade the HA surrounding them. The small fragments generated by this degradation do several things that benefit the tumor. They stimulate the growth of new blood vessels (angiogenesis), giving the tumor a blood supply.5PubMed. Hyaluronectin blocks the stimulatory effect of hyaluronan-derived fragments on endothelial cells during angiogenesis in vitro They help cancer cells stick to new surfaces and migrate to distant sites. And they reshape the physical environment around the tumor in ways that favor its spread.
One particularly important enzyme in this process is TMEM2, a surface hyaluronidase that many tumor cells use to degrade HA right at the points where they attach to surrounding tissue. Experiments knocking down TMEM2 showed that this contact-dependent HA degradation is how certain aggressive cancer cells remodel their surroundings to make adhesion, migration, and invasion easier.6Journal of Biological Chemistry. The cell surface hyaluronidase TMEM2 regulates cell adhesion and migration via degradation of hyaluronan at focal adhesion sites The cancer cell is not passively receiving HA from outside. It is actively chewing up the HA already present in tissues to clear a path for itself.
Meanwhile, some tumors also increase their own HA production. The enzymes that build HA, called hyaluronan synthases, are upregulated in several cancer types. High expression of one synthase in particular, HAS2, has been associated with worse outcomes in lung, stomach, kidney, brain, and soft-tissue cancers, among others.7Heliyon. Pan-cancer analysis reveals the potential of hyaluronate synthase as therapeutic targets in human tumors There is growing evidence that overactive HA synthases support not just tumor growth but also resistance to chemotherapy.8PubMed Central. Dissecting the role of hyaluronan synthases in the tumor microenvironment But this is the tumor’s own machinery running haywire, not something introduced from outside.
The CD44 Connection and Cancer Stem Cells
Much of the concern about HA and cancer traces back to a receptor on cell surfaces called CD44, which is the primary receptor for HA throughout the body. CD44 is widely used as a marker for identifying cancer stem cells, a small subpopulation within a tumor thought to drive its growth, spread, and ability to resist treatment.9PubMed Central. The Hyaluronan/CD44 Axis: A Double-Edged Sword in Cancer When HA binds to CD44 on these cancer stem cells, it can activate signaling pathways that promote self-renewal, survival, and the ability to colonize new tissues during metastasis.10Stem Cells Translational Medicine. Concise Review: Emerging Role of CD44 in Cancer Stem Cells: A Promising Biomarker and Therapeutic Target
This sounds alarming until you consider the context. CD44 is present on most cells in the body, not just cancer cells. It does routine jobs in healthy tissue, like mediating cell-to-cell communication and helping with wound healing. The HA-CD44 interaction becomes dangerous specifically in the context of cells that are already cancerous, where the downstream signaling has been co-opted by the tumor’s own wiring. In normal cells, the same interaction does not trigger uncontrolled growth. The receptor matters, but so does what is on the other side of it.11PubMed Central. Key Roles of Hyaluronan and Its CD44 Receptor in the Stemness and Survival of Cancer Stem Cells
A second receptor, RHAMM, also binds HA and plays a role in how cancer cells move. In prostate cancer cells, adding low-molecular-weight HA significantly increased migration, and knocking out RHAMM blocked that effect.12PubMed Central. Receptor for Hyaluronic Acid-mediated Motility (RHAMM) Is Associated With Prostate Cancer Migration and Poor Prognosis In fibrosarcoma cells, RHAMM signaling was required for low-molecular-weight HA to boost cell adhesion.13Journal of Biological Chemistry. Role of Receptor for Hyaluronic Acid-mediated Motility (RHAMM) in Low Molecular Weight Hyaluronan (LMWHA)-mediated Fibrosarcoma Cell Adhesion Again, this is low-molecular-weight HA acting on cancer cells that already exist, through receptors already overexpressed on those cells. The findings describe a mechanism tumors exploit, not something triggered by external HA exposure.
Are Skincare Products and Supplements Safe?
The HA in serums, moisturizers, and dermal fillers is typically high-molecular-weight or medium-molecular-weight material. A safety assessment published in the International Journal of Toxicology reviewed the available data and concluded that while HA does penetrate to the dermis, it likely does not play a causal role in cancer metastasis. The report noted that increased expression of HA genes in tumors is probably a consequence of cancerous growth, not a cause of it.14PubMed. Final report of the safety assessment of hyaluronic acid, potassium hyaluronate, and sodium hyaluronate This is a critical distinction: the elevated HA levels seen in many cancers are the tumor altering its own environment, not HA from outside provoking the tumor into existence.
Topically applied HA also faces a practical barrier. Skin is a formidable barrier, and high-molecular-weight HA molecules are far too large to pass through the outer layer of skin in meaningful quantities. The HA that does penetrate tends to stay in the upper skin layers, where it draws moisture and plumps the tissue. It is not entering the bloodstream in concentrations remotely comparable to what tumors produce locally through their own enzyme machinery.
Oral HA supplements are absorbed to some degree. An animal study found that HA combined with phospholipids increased serum HA concentrations for several hours after ingestion.15PubMed Central. Oral absorption of hyaluronic acid and phospholipids complexes in rats But the body already has HA circulating in the blood at all times, and the increases from oral supplementation are modest relative to what the body produces endogenously. No clinical evidence to date has linked oral HA supplements to an increased risk of developing cancer or accelerating existing tumors. If you already have a diagnosed cancer, that conversation belongs with your oncologist, because the theoretical receptor-level biology is complex enough to warrant personalized guidance. For healthy people using HA products for skin hydration or joint comfort, the safety profile is well established.
HA as a Weapon Against Cancer
In one of the more ironic twists in cancer research, the very properties that make HA useful to tumors also make it useful for delivering drugs to kill those tumors. Because many cancer cells overexpress CD44 and other HA receptors while normal cells express them at lower levels, HA can serve as a homing device. Coat a drug in HA and it preferentially finds and binds to cancer cells.16PubMed Central. Hyaluronic Acid-Based Theranostic Nanomedicines for Targeted Cancer Therapy Researchers have built HA into nanoparticles, micelles, liposomes, and hydrogels designed to improve the stability of anti-cancer drugs in the body and to concentrate those drugs where they are needed most.17PubMed Central. Hyaluronic Acid-Based Drug Delivery Systems for Cancer Therapy
On a different front, engineered hyaluronidase enzymes are being used therapeutically to strip away the HA-rich barrier that some tumors build around themselves. Dense pancreatic tumors, for instance, accumulate so much HA that the resulting gel-like stroma squeezes blood vessels shut, preventing chemotherapy drugs from reaching the cancer cells. A drug called PEGPH20, a pegylated recombinant human hyaluronidase, was developed specifically to degrade that HA barrier and restore drug delivery. Early clinical testing showed promise in treating metastatic pancreatic cancer.18PubMed. Targeting the Tumor Stroma: the Biology and Clinical Development of Pegylated Recombinant Human Hyaluronidase (PEGPH20) More broadly, hyaluronidase is being incorporated into cancer treatment regimens to remodel the tumor microenvironment, reduce stromal resistance, and help immune cells infiltrate tumors.19Materials Today Bio. From permeation enhancer to therapeutic enabler: Advances, applications, and translational perspectives in hyaluronidase-based drug delivery
HA Levels as a Diagnostic Clue
Because tumors often produce abnormally high amounts of HA, measuring HA levels in blood has attracted interest as a potential way to detect or monitor cancer. A study of upper gastrointestinal cancers found that serum HA concentrations were higher in cancer patients than in healthy controls, with a reasonably strong ability to distinguish gastric and esophageal cancers from non-cancer cases.20PubMed. Serum hyaluronic acid and laminin as potential tumor markers for upper gastrointestinal cancers More recently, serum HA levels in papillary thyroid cancer patients were significantly higher than in healthy individuals or those with a common autoimmune thyroid condition, and elevated HA correlated with whether the cancer had spread to lymph nodes.21PubMed. Elevated Cancer-Associated Hyaluronan Correlates With Diagnosis and Lymph Node Metastasis of Papillary Thyroid Cancer
These findings reinforce the pattern: elevated HA is a consequence and marker of cancer, not something external that triggers it. The body ramps up HA production in the tumor environment as part of the disease process. Measuring that elevation is potentially useful for diagnosis, which is very different from saying that HA exposure causes the cancer.
How Tumors Regulate Their Own HA Supply
A detail worth understanding is that tumors do not passively rely on whatever HA happens to be floating around. They actively regulate both HA production and HA breakdown. Cancer cells can upregulate their hyaluronan synthases to flood the local environment with HA, then use surface enzymes to chop that HA into the small fragments that stimulate blood vessel growth and cell migration. This self-contained cycle means the tumor creates its own supply of the problematic low-molecular-weight fragments, regardless of whether the person is using HA skincare or supplements.
The metabolic regulation of HA synthesis itself is tightly controlled. Research has shown that the stability and activity of HAS2, the main HA-producing enzyme in many cell types, can be dramatically altered by a chemical modification involving a sugar molecule. Without this modification, HAS2 degrades rapidly; with it, the enzyme’s half-life extends from minutes to hours.22PubMed Central. Role of UDP-N-acetylglucosamine (GlcNAc) and O-GlcNAcylation of hyaluronan synthase 2 in the control of chondroitin sulfate and hyaluronan synthesis Cancer cells, which already have altered sugar metabolism, may exploit this to keep HA production running high. The point is that the HA overabundance in tumors is internally driven by the tumor’s own reprogrammed metabolism, not by exogenous HA encountering otherwise normal cells.
When the Concern Actually Makes Sense
There is one scenario where the theoretical biology gives genuine pause. If someone already has an active cancer with CD44-overexpressing cells, it is at least theoretically possible that flooding the local area with exogenous HA could provide those cells additional ligand to bind. This is why researchers designing HA-based drug delivery systems are careful about the dose, size, and targeting of the HA they use. But there is a vast gap between the concentrations achievable through topical skincare or oral supplementation and those used in laboratory cell-culture experiments where HA promotes cancer-cell behavior. Cell culture studies bathe cells directly in HA solutions at controlled concentrations, with no skin barrier, no liver metabolism, no dilution in the bloodstream. Translating those results to real-world cosmetic or supplement use requires ignoring the body’s formidable capacity to regulate HA levels through synthesis and degradation.
For dermal fillers, which inject HA directly into tissue, the situation is slightly different from topical application because the material stays localized for months. Large population-based studies have not found an elevated cancer risk associated with HA filler use, though the number of very long-term follow-up studies remains limited. If you have had cancer in a specific area and are considering HA filler in the same region, discussing it with your physician is reasonable. For the general population, the available safety data has not raised red flags.
HA in Immune Regulation
A growing area of research examines how HA influences the immune system’s ability to recognize and fight cancer. The tumor microenvironment is not just a structural scaffold. It is an active participant in suppressing immune responses. HA-rich environments can trap immune cells, prevent them from reaching cancer cells, and alter the signals those immune cells receive. This is one reason stripping away excess HA with therapeutic hyaluronidase can allow immune cells to infiltrate tumors more effectively, a strategy being explored alongside immunotherapy.
On the other side, the intact, high-molecular-weight HA that lines healthy tissues contributes to a normal, balanced immune environment. The fragmentation of HA into small pieces during inflammation or tumor progression creates danger signals that drive chronic inflammation, which itself promotes cancer development over time.23PubMed Central. Hyaluronic Acid in Immune Response This chronic-inflammation pathway is another reason the low-molecular-weight fragments matter and the intact molecule does not carry the same risk. The immune system reads the size of the HA molecule as information about whether the tissue is healthy or damaged, and responds accordingly.