Methylglyoxal (MGO):
What It Is and Why It Matters (2026)
Information in this article shouldn't be considered medical advice. If you are considering taking manuka honey, propolis, royal jelly or bee pollen for their health benefits and are currently taking medication, please consult your doctor first.
What Methylglyoxal Is
Methylglyoxal, or MGO, is a small, organic compound classified as a reactive dicarbonyl - a highly "sticky" and reactive molecule that acts like a biological magnet, grabbing onto and damaging proteins or DNA. It is a dicarbonyl compound, meaning it has two reactive chemical groups that allow it to bond easily with other substances. While it occurs naturally in many places, its effects depend entirely on where it is and how much of it is present.
MGO can be found in multiple foods, such as instant roast coffee, fermented foods (soy sauce, wine, beer) and processed sugars. However, it is found in much higher concentrations in manuka honey compared to other foods.
Inside the body, small amounts of methylglyoxal (MGO) are naturally formed during normal sugar metabolism. At typical levels, this is simply part of ordinary biological processes and is usually managed by the body’s own regulatory systems.
Only when MGO accumulates beyond what the body can comfortably handle does it contribute to what scientists describe as “dicarbonyl stress,” which can influence the formation of compounds known as Advanced Glycation End-products (AGEs). This is an area of ongoing scientific research in relation to long-term health and ageing.
Like many naturally occurring compounds in the body, context and balance matter. The presence of MGO itself is not unusual – it is the sustained imbalance that researchers are interested in understanding.
Methylglyoxal is also found in certain foods, including New Zealand Mānuka honey, where it contributes to its distinctive properties. When consumed as part of a normal diet, dietary MGO is processed through digestion and metabolism.
Current evidence indicates that MGO present in food behaves differently from MGO produced within cells during metabolic processes. The body’s digestive and metabolic systems regulate and process dietary compounds before they circulate systemically.
Research in this area continues, and scientists distinguish between internally generated metabolic processes and compounds consumed in foods.
Ultimately, while the "sticky" nature of methylglyoxal (MGO) can be harmful when it builds up deep inside your cells, it is exactly what makes Manuka honey such a prized natural resource for wellness. In the context of a jar of honey, MGO acts as a stable, potent "superpower" that works alongside other natural compounds to support your body's external and digestive defences.
While MGO itself is a measurable compound in manuka honey. Its presence alone does not define honey as Manuka, confirm origin, or indicate quality or authenticity.
How MGO Forms in Manuka Honey
MGO in manuka honey forms through the natural conversion of dihydroxyacetone (DHA), which is found in the nectar of New Zealand’s manuka plant. When bees collect manuka nectar and convert it into honey, the DHA remains present. Over time, and under normal circumstances, this DHA gradually converts into MGO through a natural chemical process without the need for enzymes. This conversion can continue long after the honey has even been put into jars.
However, the rate and extent to which this conversion happens can vary based on: the initial concentration of DHA, storage temperature, and time. As a result, MGO levels are not static or fixed and the time of harvest, and may change during a honey’s shelf life.
Why MGO Is Measured
MGO can be measured with a high degree of consistency, making it a practical chemical marker for describing one aspect of manuka honey’s composition, measured simply in milligrams per kilogram of honey. In New Zealand, MGO testing is done alongside other tests as part of a government-enforced manuka definition, and grading / certification systems. These systems exist to provide transparency, comparability, and traceability with manuka honey, not to assess health effects or performance.
MGO Levels and Potency
Certified MGO levels are the concentration measured at the time of laboratory testing. Higher values indicate a greater concentration of methylglyoxal present in that specific sample of honey at the time of testing.
Terms such as “strength” and “potency” are often used informally regarding differing MGO levels, however, these terms are not scientific or regulatory classifications and do not have defined meanings within New Zealand standards.
The MGO number also does not describe flavour, texture, freshness, or floral purity. Nor does it confirm that it complies with any official definitions or certification requirements on its own.
Stability and Change Over Time
MGO levels in manuka honey can change after harvest due to the ongoing conversion of DHA into MGO. While DHA still exists in the honey, the constant conversion can hold the MGO levels, and sometimes grow them, over an extended period of time. However, once the DHA has run out, the MGO levels will drop slowly over time as the MGO deteriorates. This means that the laboratory results only reflect that moment in time during testing, not a fixed value that will hold indefinitely. Storage conditions, particularly temperature, can influence the rate of this conversion.
Limitations of Measuring MGO Alone
Measuring only MGO does not mean that honey is authentic New Zealand manuka honey. MGO is not unique to manuka honey, manuka honey is only capable of containing stable levels of MGO for far longer than other sources. So MGO alone does not confirm a honey’s floral source, geographic origin, or compliance with regulatory definitions.
New Zealand has an official definition for manuka honey, administered by the Ministry for Primary Industries (MPI). This definition is based on a combination of chemical and DNA markers. All New Zealand manuka honey must meet these requirements, particularly for international export as manuka honey.
Why Balance Matters More Than a Single Number
Because manuka honey is chemically complex, with MGO representing only one compound, multi-factor frameworks have been put in place to ensure authenticity.
One such framework is the UMF (Unique Manuka Factor) grading system, which incorporates several chemical indicators and verifies consistency within defined parameters:
- MGO (Methyglyoxal) for potency
- Leptosperin (from the manuka tree) for Authenticity
- DHA (Dihydroxyacetone) for shelf life
- HMF (Hydroxymethylfurfural) for freshness.
UMF is run by and independent industry body and operates separately from the MPI regulatory definition, while still adhering to it. It’s role is to provide a standardised grading framework.
