What Is Methylglyoxal?

Methylglyoxal (MGO) is a naturally occurring organic compound — chemically classified as a dicarbonyl — that forms in Manuka honey through the conversion of dihydroxyacetone (DHA), a compound found in high concentrations in Manuka flower nectar. The transformation from DHA to MGO occurs gradually during and after honey production, which is why freshly harvested Manuka honey may have lower MGO levels that increase over time during storage.

The discovery of MGO as the primary active compound in Manuka honey is credited to Professor Thomas Henle and his team at the Technical University of Dresden, who published their findings in the early 2000s, fundamentally changing our understanding of why Manuka honey is so potent.

How MGO Kills Bacteria

MGO is a highly reactive compound. Its antibacterial mechanism works through a process called glycation — it reacts with proteins and DNA in bacterial cells, disrupting their structure and function. Specifically, MGO:

  • Reacts with amino groups in bacterial proteins, impairing their ability to function.
  • Damages bacterial DNA, inhibiting replication.
  • Disrupts the integrity of bacterial cell membranes.

Crucially, this mechanism is different from most antibiotics, which typically target specific biological pathways. Because MGO attacks multiple targets simultaneously, it is less likely to contribute to antibiotic resistance — a significant area of scientific interest.

MGO and Antibiotic-Resistant Bacteria

The rise of antibiotic-resistant organisms (so-called "superbugs") is one of the most serious challenges in modern medicine. Research has shown that Manuka honey, and MGO specifically, retains antibacterial activity against several resistant strains, including:

  • Staphylococcus aureus (including MRSA)
  • Pseudomonas aeruginosa
  • Escherichia coli
  • Helicobacter pylori

While these findings are largely from laboratory studies, they have driven significant interest in Manuka honey as a potential adjunct in clinical settings, particularly for wound care.

The DHA-to-MGO Conversion

Understanding the origin of MGO helps explain some important characteristics of Manuka honey:

  1. MGO increases with age: Because DHA continues converting to MGO after harvest, properly stored Manuka honey may actually have a higher MGO concentration after 1–2 years than when first bottled.
  2. Fresh honey needs testing: Producers must test MGO levels at bottling to ensure accurate labelling, as the concentration changes over time.
  3. Temperature matters: Higher storage temperatures accelerate the DHA-to-MGO conversion, while refrigeration slows it. Room temperature storage is recommended.

What Research Is Still Ongoing?

While the antibacterial properties of MGO are well-established, scientists continue to explore:

  • The role of MGO and other Manuka honey compounds in wound healing and tissue regeneration.
  • Potential anti-cancer properties of MGO at the cellular level (early-stage research).
  • Interactions between MGO and the human gut microbiome.
  • Optimal delivery methods for therapeutic applications.

The field is active and evolving. As clinical trials expand, our understanding of exactly how and when MGO is most effective will continue to grow.

Key Takeaway

MGO is not just a marketing number — it is a scientifically characterised compound with a well-understood mechanism of action. The MGO rating on a jar of Manuka honey is a meaningful, measurable indicator of its antibacterial potency, grounded in genuine chemistry and an expanding body of research.