The science
Not just Manuka — the science behind medical grade honey.
Manuka leads the category, but it doesn't own it. Peroxide-driven honeys, polyphenol-rich Honeydew, Ulmo, Heather, Buckwheat and Tualang each carry their own chemistry — and their own clinical case for medical grade use.
Activity chemistry
MGO, DHA — and the peroxide problem.
Most honeys derive their antimicrobial activity from hydrogen peroxide, generated when the bee enzyme glucose oxidase encounters glucose in the wound bed. Peroxide activity is real — but fragile. It collapses under heat, light, dilution, and tissue catalase.
Manuka's signature is methylglyoxal (MGO), formed by the slow, non-enzymatic conversion of dihydroxyacetone (DHA) from the nectar of Leptospermum scoparium. MGO is stable, dose-dependent, and survives gamma irradiation.
This is the chemical reason a 100% Manuka dressing can carry meaningful activity through manufacturing, sterilisation, and application — without claiming antimicrobial on pack.
Comparison
| Property | Peroxide honey | Manuka (MGO) |
|---|---|---|
| Heat stable | No | Yes |
| Catalase resistant | No | Yes |
| Dose quantifiable | Variable | mg/kg MGO |
| Survives gamma | Partial | Yes |
Rheology & crystallisation
Thixotropic by nature.
Manuka is naturally thixotropic — it behaves as a gel at rest and flows under shear. No carbomers, no gelling agents, no excipients you'll have to defend in your dossier. Jelly-bush (Australia) and Heather (Scotland) share this rheology at a fraction of the cost when MGO isn't required.
The crystallisation challenge.
100% Manuka crystallises. It is a natural process driven by a higher glucose-to-fructose ratio than honeys like Acacia. For a medical device this is a stability and dosing question, not a quality failure — and one that has elegant formulation solutions.
Beyond Manuka
The other medical-grade candidates.
Manuka's MGO chemistry made it the category leader, but it isn't the only honey with a credible mechanism of action. Each of these has peer-reviewed evidence behind it — and a place in the conversation.
Ulmo (Chile)
Eucryphia cordifolia
Peroxide + polyphenols
Comparative trials show greater efficacy than Manuka against certain MRSA strains in vitro. Strong wound-care candidate in South America.
Heather (UK / Europe)
Calluna vulgaris
Peroxide + thixotropic rheology
Naturally gel-like — rare outside Manuka. Used in Scottish and Scandinavian wound applications; no MGO but strong osmotic and peroxide activity.
Honeydew (Europe)
Forest secretions, not nectar
Polyphenols + oligosaccharides
Higher mineral and antioxidant load than nectar honeys. 2024 data suggest stronger antiviral activity than Manuka in specific models.
Buckwheat (N. America / E. Europe)
Fagopyrum esculentum
Polyphenols + peroxide
Highest phenolic content of common honeys. Cochrane-grade evidence as a paediatric cough antitussive (vs placebo and dextromethorphan).
Tualang (Malaysia)
Koompassia excelsa
Phenolics + flavonoids
Studied in burns, oral mucositis and diabetic wounds. Comparable antibacterial profile to Manuka against several Gram-negative pathogens.
Jelly-bush (Australia)
Leptospermum polygalifolium
MGO (same family as Manuka)
Australian Leptospermum cousin — frequently equal or higher MGO than NZ Manuka. The basis of Medihoney's original supply.
Sidr (Yemen / Middle East)
Ziziphus spina-christi
Peroxide + traditional use
Long ethnomedical history; emerging lab data on antibacterial and antifungal activity. Premium-priced and supply-constrained.
Acacia & clover (global)
Robinia, Trifolium spp.
Peroxide + low HMF
Mild peroxide activity; valuable as a base or supplemented honey (see L-Mesitran). Crystallise slowly — useful in stable formulations.
Activity drivers vary: peroxide (glucose-oxidase generated, fragile but ubiquitous), methylglyoxal (Manuka and Jelly-bush, stable and quantifiable), bee defensin-1 (a peptide present at variable levels across honeys, central to Revamil), polyphenols and flavonoids (Honeydew, Buckwheat, Tualang) and osmolarity (every honey, by virtue of being honey). A medical-grade specification picks one or more of these and engineers them to survive sterilisation and shelf life.
Sterilisation
Why medical honey is gamma irradiated.
Honey is dense, viscous and water-active in ways that defeat conventional terminal sterilisation. Heat denatures peroxide activity and accelerates HMF formation; steam can't penetrate a sealed honey matrix evenly. That is why the majority of medical honey-based products are terminally sterilised by gamma irradiation as a finished good.
Industry standard
Gamma (Co-60)
Deep, uniform penetration through dense honey and primary packaging. Validated to ISO 11137. Preserves MGO; modest, predictable effect on peroxide activity. The default for almost every medical-grade Manuka product on the market.
Alternative
E-beam
Faster dose delivery and tighter dose distribution than gamma, but limited penetration depth — suitable for thin dressings, tulles and low-density formats rather than bulk honey tubes or jars.
Alternative
EtO (ethylene oxide)
A surface sterilant — gas does not penetrate a sealed honey matrix, and residuals are tightly regulated under ISO 10993-7. Used for combination devices and dressing carriers, rarely for the honey itself.