Manuka Honey and Biofilms: What the Studies Show
Understanding Why Chronic Wounds Resist Treatment
Published Jan 15, 2025 | Citations and claims revised October 15, 2026
The Biofilm Problem
Bacteria in chronic wounds often live inside biofilms. These protective structures are held together by an extracellular polymeric substance (EPS) matrix, a dense scaffold of polysaccharides, proteins, and extracellular DNA that shields bacterial colonies from antibiotics and immune cells. A wound can appear infected but not respond to treatment because drugs struggle to penetrate the EPS barrier. Biofilm bacteria are often reported to tolerate antimicrobials at levels up to 1,000 times higher than free-floating cells (Mah & O'Toole, 2001, Trends in Microbiology). A 2017 meta-analysis found biofilm in 78.2% of chronic wounds across nine studies and 185 wounds (Malone et al., 2017). That is why researchers are testing biofilm-active treatments, including honey.
What Makes the EPS Matrix So Resistant
Biofilms are not simply colonies of bacteria. They are organized microbial communities with architectural structure and chemical communication systems. The EPS matrix protects bacteria in multiple ways: it physically blocks antibiotics from reaching cells, sequesters antimicrobial molecules before they can act, and creates oxygen gradients that slow bacterial metabolism. Slower metabolism makes bacteria less vulnerable to drugs that target actively dividing cells.
Common wound pathogens like Staphylococcus aureus (including MRSA), Pseudomonas aeruginosa, and Enterococcus species form robust biofilms in chronic wounds. These organisms coordinate their behavior through quorum sensing, a chemical signaling system that activates biofilm formation when bacterial density reaches critical thresholds. Once established, biofilms are nearly impossible to eradicate with antibiotics alone. The M03 Biofilm Disruption Protocol outlines the clinical response to this challenge.
Physical Barrier
The EPS matrix creates a diffusion barrier that prevents antibiotics from reaching bacteria at therapeutic concentrations. Only small molecules can penetrate effectively.
Chemical Inactivation
Enzymes within the biofilm matrix neutralize antimicrobials before they reach bacterial cells. Beta-lactamases destroy penicillin-class antibiotics on contact.
Metabolic Dormancy
Bacteria deep in biofilms enter slow-growth states where they divide rarely. Most antibiotics only kill actively growing cells, making dormant bacteria functionally immune to treatment.
Three Properties Researchers Study
Researchers point to three properties of manuka honey that could work together against biofilms: methylglyoxal, acidity, and high sugar content. Most of this evidence comes from laboratory dishes, not patients. The sections below describe each property and then what the studies actually found.
Three Properties
Methylglyoxal
Methylglyoxal is a small, reactive molecule that can damage bacterial proteins and DNA through glycation.
Possible factor: Low pH
Honey is acidic, with a typical pH of about 3.2 to 4.5. Acidity can slow bacterial growth.
Possible factor: Osmolarity
High sugar concentration creates osmotic pressure that draws water out of bacterial cells.
Methylglyoxal and Protein Damage
Methylglyoxal (MGO) is a small, reactive molecule with a molecular weight of just 72 Da. In the lab, it reacts with amino acids in bacterial proteins and with nucleotides in DNA. In one study, MGO inhibited 53 multidrug-resistant Pseudomonas aeruginosa isolates, and bacterial efflux pumps did not appear to recognize it (Hayashi et al., 2014, Frontiers in Microbiology). MGO is not the whole story, though. Mavric et al. (2008, Molecular Nutrition & Food Research) identified it as the dominant antibacterial constituent of New Zealand manuka honey, and Lu et al. (2014, PeerJ) found that MGO alone, or MGO with sugar, did not effectively remove established Staphylococcus aureus biofilms, so other honey components also appear to matter.
Glycation produces advanced glycation end-products (AGEs) in the lab. Unlike many antibiotics, which hit one specific pathway, MGO acts on several cell components at once, which may make resistance harder to develop. Harder is not impossible, as the next study shows.
Bacteria can adapt to honey. Camplin & Maddocks (2014) recovered Pseudomonas aeruginosa from honey-treated biofilms that were less susceptible to manuka honey, showed higher resistance to two antibiotics, and formed more biofilm than the original strains. The authors suggest that sub-lethal honey levels inside a biofilm could select for resistance. This is a lab result, but it argues against claims that bacteria cannot develop resistance to honey. For more on MGO chemistry, see the Methylglyoxal Antibacterial Science page.
Acidity and Bacterial Enzymes
Honey is far more acidic than healthy tissue, which sits near neutral pH. Acidity can limit bacterial growth because many bacterial enzymes work best near neutral pH. Wound pH has also been studied in relation to protease activity in chronic wounds. These ideas come from laboratory and mechanistic work and have not been proven to explain how honey performs in patients.
Researchers have proposed that lowering wound pH could reduce the activity of proteases that chronic wounds produce in excess. Whether honey does this in real wounds, and whether it matters for healing, is not settled. The wound bed preparation steps in the M03 Clinical Application Standards are written as training material and are not a substitute for clinical guidance.
Osmotic Pressure
Honey is a supersaturated sugar solution with very high osmolarity. In the lab, that draws water out of bacterial cells, and bacteria need water to function. Clinicians also describe honey drawing fluid from wound tissue, which may help with autolytic debridement, where the body's own enzymes break down dead tissue. These are descriptions of mechanisms, and clinical trials are needed to show whether they translate into better healing.
Whether these effects add up to better healing in patients is a question for clinical trials, and the evidence so far is mixed and mostly low quality.
A Note on Comparing Treatments
No comparison table is shown here. Published head-to-head evidence on biofilm-active wound agents is limited, and ratings of penetration and resistance risk would go beyond what the studies support.
What the Studies Show
Laboratory studies report that manuka honey can disrupt biofilms formed by MRSA and other bacteria. Clinical evidence is less clear. A Cochrane review found that most trial evidence on honey for wounds is low or very low quality, and it did not examine biofilm. Treat the findings below as lab results and reviews, not proof that honey will clear a biofilm in a patient.
Key Clinical Findings
- Staphylococcus aureus biofilms (lab): Lu et al. (2014) in PeerJ found manuka-type honeys were more effective than clover honey or sugar solution at preventing and removing S. aureus biofilms, including MRSA strains. A manuka honey with 958 mg/kg MGO removed almost all established biofilms at 16 to 32 percent honey. MGO alone did not do the same.
- Pseudomonas aeruginosa motility (lab): Roberts et al. (2015) in the Journal of Antimicrobial Chemotherapy reported that manuka honey reduced swarming and swimming motility by suppressing flagella-related genes. The authors say this needs testing in living systems.
- A caution on resistance (lab): Camplin & Maddocks (2014) in Annals of Clinical Microbiology and Antimicrobials recovered P. aeruginosa from honey-treated biofilms with higher honey resistance, cross-resistance to rifampicin and imipenem, and more biofilm formation.
- Healing in patients (review): Jull et al. (2015) in the Cochrane Database of Systematic Reviews reviewed 26 trials with 3,011 participants. It found honey likely heals partial-thickness burns and infected post-operative wounds faster than some comparison treatments, while evidence for venous leg ulcers and diabetic foot ulcers was unclear. Most evidence was low or very low quality, and the review does not address biofilm.
FDA-Cleared Medical Honey Products
This list is pulled live from an FDA database when the page loads. Clearance means the FDA found a product substantially equivalent to an existing device. It does not mean the FDA has judged that the product removes biofilms. See our medical-grade standards page.
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References
- Mah, T.F. & O'Toole, G.A. (2001). Mechanisms of biofilm resistance to antimicrobial agents. Trends in Microbiology, 9(1), 34-39. Verifying...
- Hayashi, K., Fukushima, A., Hayashi-Nishino, M. & Nishino, K. (2014). Effect of methylglyoxal on multidrug-resistant Pseudomonas aeruginosa. Frontiers in Microbiology, 5, 180. Verifying...
- Mavric, E. et al. (2008). Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka (Leptospermum scoparium) honeys from New Zealand. Molecular Nutrition & Food Research, 52(4), 483-489. Verifying...
- Lu, J. et al. (2014). Manuka-type honeys can eradicate biofilms produced by Staphylococcus aureus strains with different biofilm-forming abilities. PeerJ, 2, e326. Verifying...
- Roberts, A.E.L., Maddocks, S.E. & Cooper, R.A. (2015). Manuka honey reduces the motility of Pseudomonas aeruginosa by suppression of flagella-associated genes. Journal of Antimicrobial Chemotherapy, 70(3), 716-725. Verifying...
- Camplin, A.L. & Maddocks, S.E. (2014). Manuka honey treatment of biofilms of Pseudomonas aeruginosa results in the emergence of isolates with increased honey resistance. Annals of Clinical Microbiology and Antimicrobials, 13, 19. Verifying...
- Jull, A.B. et al. (2015). Honey as a topical treatment for wounds. Cochrane Database of Systematic Reviews, (3), CD005083. Verifying...
- Malone, M. et al. (2017). The prevalence of biofilms in chronic wounds: a systematic review and meta-analysis of published data. Journal of Wound Care, 26(1), 20-25. Verifying...
Latest Biofilm Research
The following articles are fetched live from the NCBI PubMed database using the E-utilities API. These represent the most recent peer-reviewed publications on Manuka honey and biofilm disruption in wound care.
Fetching latest research from PubMed...
Manuka Honey and Biofilms: What the Research Shows
A conversation about the research on manuka honey and biofilms. Jordan and Quinn discuss what laboratory studies report about methylglyoxal, acidity and osmotic pressure, and where the evidence is still limited.
Continue Exploring the Science
Researchers are still working out how MGO, acidity and sugar content act together, and the clinical evidence is still developing. For chemistry, see the MGO science page. For research trials, see the Clinical Research Hub.