Manuka honey does show antifungal activity in laboratory studies, inhibiting the growth of several clinically relevant fungi including Candida species and certain dermatophytes. But the picture is more nuanced than the marketing might suggest: the effect is largely fungistatic, meaning it slows or halts fungal growth rather than killing fungal cells outright. The concentration required is high, the contact time needs to be long, and clinical trials in humans remain scarce. What the research reveals is a substance with genuine but modest antifungal potential that works best as a complement to conventional treatments, not a replacement.
How Manuka Honey Works Against Fungi
Manuka honey’s antimicrobial reputation rests primarily on its antibacterial properties, but the same underlying mechanisms exert pressure on fungal cells too. The honey creates a hostile environment through several overlapping factors: its naturally acidic pH of around 3.5, its high sugar content creating intense osmotic pressure, and the presence of hydrogen peroxide generated enzymatically when the honey is diluted. Manuka honey also contains methylglyoxal, aromatic acids, flavonoids, polyphenols, and a bee-derived peptide called defensin-1, all of which contribute to its antimicrobial activity.1Phytomedicine Plus. Glycyrrhiza glabra hydroethanolic extract and manuka honey alone and in combination inhibit bacterial and fungal planktonic cells and biofilms
For fungi specifically, the osmotic pressure is a key player. The extremely high sugar concentration pulls water out of fungal cells, dehydrating them and shrinking their structures. When this osmotic stress is combined with the acidic environment and the direct chemical effects of methylglyoxal, fungal cell membranes can lose integrity. In biofilm-forming organisms, this disruption extends to the extracellular matrix that holds the community of cells together.1Phytomedicine Plus. Glycyrrhiza glabra hydroethanolic extract and manuka honey alone and in combination inhibit bacterial and fungal planktonic cells and biofilms
What makes this mechanism profile interesting is that it attacks fungi through physical and chemical stress simultaneously. A fungal cell can sometimes adapt to a single threat, but the combined assault of dehydration, acid, and reactive chemical compounds is harder to develop resistance against. That said, “harder” does not mean impossible, and the degree of stress depends heavily on how much honey is present.
Which Fungi Respond, and How Effectively
The antifungal activity of Manuka honey varies considerably depending on the fungal species being tested. Research on clinically important yeasts found that minimum inhibitory concentrations ranged from about 8% to more than 44% honey by weight, depending on both the honey sample and the yeast strain involved.2PubMed. In vitro activity of Western Australian honeys and Manuka honey against clinically important yeasts That is an enormous range, and it underscores an important point: Manuka honey is not uniformly effective against all fungi.
Against Candida albicans, one of the most common fungal pathogens in humans, Manuka honey at a 40% concentration showed effectiveness in lab testing. But against dermatophytes, the fungi responsible for conditions like athlete’s foot and ringworm, results were weaker. One study found that Manuka honey exhibited weak activity against Trichophyton mentagrophytes, achieving only about 45% inhibition, and showed no meaningful activity at all against Trichophyton rubrum at lower concentrations. Even at 40%, the effect against T. mentagrophytes was only partial.3Scientific Reports. Agastache honey has superior antifungal activity in comparison with important commercial honeys
When researchers tested Manuka honey against filamentous moulds, including 13 clinical isolates, they found that antifungal activity correlated more closely with exposure time than with concentration. In other words, leaving the honey in contact with mould cultures for longer mattered more than simply increasing the amount of honey.4PubMed Central. In Vitro activity of Manuka Honey and polyhexamethylene biguanide on filamentous fungi and toxicity to human cell lines This is a practical consideration: for any topical application, maintaining sustained contact is likely more important than simply slathering on a thicker layer.
Fungistatic, Not Fungicidal
A critical distinction that often gets lost in popular discussions is whether Manuka honey kills fungi or merely stops them from growing. The evidence points firmly toward the latter. Research on dermatophytes found that Manuka honey showed only fungistatic activity, meaning it inhibited growth without actually destroying the organisms.3Scientific Reports. Agastache honey has superior antifungal activity in comparison with important commercial honeys
This matters because a fungistatic agent requires the immune system or another treatment to finish the job. If you remove the honey, surviving fungal cells can resume growing. Prescription antifungal medications, by contrast, often aim to be fungicidal at therapeutic doses, actually destroying fungal cells rather than just holding them at bay. For someone relying on Manuka honey alone to clear a fungal infection, this distinction is the difference between suppressing symptoms temporarily and resolving the infection. The honey can help tilt the battlefield in the immune system’s favor, but it is unlikely to clear a stubborn infection on its own.
The Concentration Paradox
Perhaps the most counterintuitive finding in this research is what happens at low concentrations. When Manuka honey was tested against yeasts at relatively low concentrations, it actually enhanced fungal growth compared to untreated controls. Only at and above roughly 12% honey by weight did the dose-dependent inhibitory effect kick in.2PubMed. In vitro activity of Western Australian honeys and Manuka honey against clinically important yeasts The same pattern appeared in biofilm studies: established biofilms exposed to honey concentrations below 10% actually showed increased biomass, while concentrations above 10% reduced it markedly.5Wounds UK. Inhibition of biofilms through the use of Manuka honey
This makes intuitive sense when you think about what honey is: a sugar-rich substance. At low concentrations, the sugars serve as food for microorganisms without imposing enough osmotic stress to be harmful. Only at higher concentrations does the osmotic pressure overwhelm the organisms’ ability to cope. The practical implication is stark: applying Manuka honey in too-thin a layer, or allowing it to become heavily diluted by wound fluid or sweat, could theoretically encourage rather than discourage microbial growth.
In wound-care settings, researchers have noted that Manuka honey is unlikely to be diluted by more than tenfold in a wound environment, which should keep concentrations in the inhibitory range. But they emphasize the need to apply and maintain honey at an appropriate concentration.5Wounds UK. Inhibition of biofilms through the use of Manuka honey For someone using Manuka honey at home for a minor skin issue, this means generous application matters more than people might assume.
Breaking Through Biofilms
Fungi and bacteria often protect themselves by forming biofilms, communities of cells encased in a sticky extracellular matrix that shields them from both the immune system and antimicrobial agents. Biofilms are notoriously difficult to treat and are a major reason why certain infections, particularly those on wounds or medical devices, become chronic.
Manuka honey has demonstrated the ability to disrupt biofilms, but with a caveat: it takes considerably higher concentrations to break apart an established biofilm than to prevent one from forming in the first place. In studies where 24-hour-old biofilms were exposed to Manuka honey, biomass was markedly reduced after 24 hours of contact with concentrations above 10%, while prevention of biofilm formation required lower concentrations.5Wounds UK. Inhibition of biofilms through the use of Manuka honey This suggests a preventive role may be more practical than a curative one when biofilms are involved.
The biofilm research also reinforces the exposure-time finding from mould studies. Breaking through a mature biofilm is not just about concentration: it requires sustained contact. A quick smear of honey followed by a rinse is not going to accomplish much against an entrenched fungal community.
Pairing Manuka Honey with Antifungal Drugs
One of the more promising lines of research involves using Manuka honey alongside conventional antifungal medications rather than as a standalone treatment. A study on Malassezia pachydermatis, a yeast that causes skin infections in animals and occasionally in immunocompromised humans, tested Manuka honey in combination with four standard antifungal drugs: clotrimazole, fluconazole, miconazole, and itraconazole. In every combination, the effect was additive, meaning the honey and the drug together performed better than either one alone.6PubMed. Efficacy of manuka honey with conventional antifungals on Malassezia pachydermatis
An additive effect is not the same as a synergistic one (where 1+1 equals more than 2), but it is still clinically meaningful. If honey can contribute even modest antifungal pressure alongside a prescription medication, it could allow the drug to work more effectively or at a lower dose. This idea has been explored more extensively in antibacterial contexts, where Manuka honey has been shown to enhance the effectiveness of antibiotics.7Mini-Reviews in Medicinal Chemistry. Benefits of Manuka Honey in the Management of Infectious Diseases: Recent Advances and Prospects Whether the same principle holds as robustly for antifungals still needs more investigation, but the early signals are encouraging.
From Lab Dish to Real Skin
The biggest gap in the Manuka honey antifungal story is the leap from laboratory results to clinical outcomes in actual patients. Most of the evidence discussed so far comes from in vitro studies, where honey is added directly to fungal cultures in tightly controlled conditions. The human body is far messier. Skin has varying pH and moisture levels, the immune system is doing its own work, and patients rarely apply a product with the precision of a lab technician.
One of the few clinical trials to directly test Manuka honey against a fungal organism in humans looked at Candida auris, an emerging drug-resistant yeast that has become a serious concern in healthcare settings. Researchers in Hong Kong tested a Manuka honey body wash combined with oral probiotics among residents of older-adult care homes colonized with C. auris. The intervention group cleared colonization at a median of 224 days compared to 427 days in the control group. That sounds impressive on the surface, but the difference did not reach statistical significance.8PubMed Central. Natural clearance time and effect of manuka honey body wash and oral probiotics on colonization of Candidozyma auris (Candida auris) among residents of older adults homes in Hong Kong
This trial is a useful reality check. Even with a body wash specifically formulated with Manuka honey and used daily over months, the benefit against a real-world fungal colonization was suggestive at best. The study was also complicated by the use of oral probiotics alongside the honey wash, making it impossible to attribute any effect specifically to the honey. More and larger trials are needed before anyone can claim that Manuka honey reliably treats or prevents fungal infections in clinical settings.
Not All Honeys Are Created Equal
Manuka honey often dominates the conversation around medicinal honey, but it is not necessarily the most antifungal honey available. A direct comparison of Manuka honey with several Western Australian honeys found that some of them performed better against clinically important yeasts. Honeys derived from Blackbutt, Jarrah, and Karri eucalyptus trees showed the highest overall antifungal activity in the study.2PubMed. In vitro activity of Western Australian honeys and Manuka honey against clinically important yeasts Similarly, research on dermatophytes found that an Agastache-derived honey had superior antifungal activity compared to Manuka.3Scientific Reports. Agastache honey has superior antifungal activity in comparison with important commercial honeys
This does not mean Manuka honey is useless for antifungal purposes, but it does mean that its premium price tag is not necessarily buying you superior antifungal performance. The antimicrobial profile of any honey depends on the floral source, the bee species, local growing conditions, and post-harvest handling. Manuka honey’s unique selling point has always been its high methylglyoxal content, which gives it strong antibacterial properties. But antibacterial potency and antifungal potency are not the same thing, and some honeys that are less celebrated may actually be better choices for fungal concerns.
Heat and Storage Affect Potency
If you do decide to use Manuka honey for its antimicrobial properties, how you store it matters. Research on honey’s antifungal activity against Candida albicans has shown that heating significantly reduces effectiveness. Non-heated honey inhibited fungal growth at a 40% concentration, while honey heated to progressively higher temperatures required increasingly higher concentrations to achieve the same effect. The antifungal activity declined in a clear stepwise fashion as heating temperature increased.9Asian Pacific Journal of Tropical Biomedicine. Influence of temperature on the inhibitory potency of Eucalyptus honey against Candida albicans
The likely explanation is that heat degrades hydrogen peroxide-producing enzymes and heat-sensitive bioactive compounds. This has practical implications for anyone buying Manuka honey with therapeutic intent: honey that has been heavily processed or pasteurized at high temperatures may retain its sweet flavor but lose a meaningful fraction of its antimicrobial power. Medical-grade Manuka honey products, such as those used in wound dressings, are typically gamma-irradiated for sterility rather than heat-treated, precisely to preserve these bioactive components. If you are choosing a store-bought Manuka honey for topical use, raw or minimally processed varieties are likely to retain more of the compounds that matter.
What the UMF and MGO Ratings Actually Tell You
Manuka honey is commonly graded by its Unique Manuka Factor (UMF) rating or its methylglyoxal (MGO) content. These ratings were developed primarily to standardize the honey’s antibacterial potency, and higher-rated honeys command substantially higher prices. But there is an important gap here for fungal concerns: the UMF and MGO systems measure methylglyoxal concentration, and while methylglyoxal contributes to both antibacterial and antifungal activity, it is only one piece of the antifungal puzzle. The osmotic pressure, pH, hydrogen peroxide production, and other bioactive compounds also play roles, and these are not captured by the UMF number on the label.
A honey with a very high UMF rating is not guaranteed to be proportionally more effective against fungi. The research consistently shows that the total antifungal effect depends on the combined action of multiple components, and the relative importance of each component varies by fungal species. For someone specifically interested in antifungal properties, chasing the highest UMF rating and paying the associated premium may not deliver proportional benefits. A moderately rated medical-grade Manuka honey applied at sufficient concentration and contact time could be just as useful as a premium-priced product applied sparingly.
Who Should and Should Not Try This
For minor superficial fungal concerns on intact skin, applying Manuka honey topically carries very little risk for most people. Honey is generally well-tolerated, and allergic reactions are uncommon though not impossible, particularly in people with bee-related allergies. Medical-grade Manuka honey dressings are already used in wound care in many countries and have established safety profiles.
Where caution is warranted is in relying on Manuka honey as a primary treatment for a diagnosed fungal infection, especially systemic or deep-seated ones. Oral candidiasis, invasive fungal infections, and widespread dermatophyte infections need conventional antifungal therapy. The evidence for Manuka honey is too preliminary, too concentrated in lab settings, and too inconsistent across fungal species to justify delaying proven treatment. People with diabetes should be particularly careful about applying any sugar-rich substance to broken skin, even medical-grade honey, without clinical guidance.
The most reasonable application based on current evidence is as an adjunct: using Manuka honey alongside prescribed antifungal treatment, in wound dressings where biofilm prevention is a concern, or as a general skin-care product for people prone to superficial fungal issues. For anyone considering this, medical-grade products designed for topical use are preferable to food-grade honey from a supermarket shelf, which may have been heated during processing and is not sterile.