Manuka honey stands out in the vast array of honey varieties due to its distinctive antibacterial properties, particularly its non-peroxide antibacterial activity (NPA). One of the primary factors contributing to this uniqueness is its MGO content. This article will explore the specifics of MGO, its role in defining the beneficial characteristics of Manuka honey, and the importance of considering the MGO content when assessing the quality of Manuka honey.

What does MGO mean in Manuka Honey?
The term MGO stands for methylglyoxal, a natural compound found in Manuka honey. It serves as the backbone for many of the honey’s therapeutic properties, including accelerating wound healing, promoting epithelial cell regeneration, and assisting in ulcer treatment.
MGO concentrations in Manuka honey can range quite widely, from as low as 80 milligrams per kilogram (mg/kg) to exceeding 1800mg/kg. To put that into perspective, Manuka honey generally contains nearly 100 times more MGO than conventional types of honey.
A pertinent question arises — how does the MGO end up in the honey? It’s genuinely a marvel of nature. Bees produce MGO when they break down the Manuka nectar using enzymes in their stomachs. They convert a compound found in the nectar, known as dihydroxyacetone (DHA), into MGO. One intriguing fact is that this transformative process of producing MGO continues even post-harvest. For a period extending between 12-24 months post-harvest, MGO concentration increases as DHA levels diminish.
Understanding the MGO Rating — An Incomplete Measure
Developing a system to measure the MGO content in Manuka honey was first initiated by Dr. Peter Molan from the University of Waikato in New Zealand. His system, named “Molan Gold Standard”, gave us a viable metric to evaluate Manuka honey.
Contrary to what one might expect, research led by Molan highlighted that the non-peroxide, or special antibacterial activity of Manuka honey cannot solely be credited to MGO. While there’s a moderate correlation between MGO levels and antibacterial activity, they’re not exactly proportional — they don’t mirror one another in a 1:1 ratio. For instance, honey containing 300 mg/kg of MGO has approximately twice the rating for non-peroxide antibacterial activity as honey containing 100 mg/kg of MGO. However, you’d expect it to be three times higher under a directly proportional relationship.
In addition, MGO acts differently in honey than in isolation, with other elements present in the honey that alter how this chemical interacts with bacteria. This highlights that MGO is only a part of the picture and not the sole contributor behind the significant non-peroxide antibacterial activity of Manuka honey.
Ensuring Authenticity and Quality: MGO is Not the Only Factor
Quality assurance is paramount when it comes to Manuka honey — an aspect that can’t solely rely on MGO measurement. Unfortunately, MGO can be produced industrially and added to honey. This practice gives birth to ‘fake’ Manuka honey, which can be misleading for consumers. Therefore, measuring only MGO doesn’t guarantee the authenticity and quality of Manuka honey.
MGO Concentration Over Time and Storage Conditions
It’s important to note that the MGO content of Manuka honey changes over time. The MGO concentration initially increases rapidly during the first couple of years after harvest due to the chemical conversion of DHA to MGO. However, as the DHA supply gets used up, the rate of conversion declines. In fact, in honey nearing the end of a five-year shelf life, the MGO concentration begins to drop due to insufficient DHA availability.
Additionally, storage conditions such as temperature can impact the rate of DHA to MGO conversion. The ideal storage temperature to balance the DHA to MGO conversion is at or below 23°C.
The Role of UMF™ Grading System
The ideal solution to the aforementioned quality assurance problem lies in the UMF™ (Unique Manuka Factor) grading system. This system offers a more holistic evaluation than just relying on MGO measurement. Genuine Manuka honey from New Zealand bears both a MGO rating and a UMF™ grade.
By opting for Manuka honey licensed by the UMFHA (Unique Manuka Factor Honey Association), you ensure you’re receiving an authentic, quality product. So, when purchasing, it’s advised to look for a UMF™ grade along with the MGO rating to guarantee authenticity.
Which MGO Manuka Honey is Right for You?
The choice of MGO levels depends largely on your individual health goals.
If you’re looking for a honey that is good for everyday use, MGO 83+ would be a great choice. It’s great for cooking and baking, and has all the vitamins and minerals your body needs—plus it tastes delicious! Some of the most commonly found grades in this range include MGO 83+, MGO 90+, MGO 100+, MGO 120+, MGO 150+, and MGO 250+.

If you want a little bit of medicinal power but don’t want to go above and beyond with the antibacterial properties, then we recommend the MGO 263+ variety. The most common grades in this range are MGO 263+, MGO 300+, MGO 302+, MGO 400+, and MGO 500+.
If you’re looking for something that packs a one-two punch against bacteria and other pathogens, we suggest MGO 514+. This honey has high levels of both antibacterial activity and medicinal properties. Some of the most common grades in this range are MGO 550+, MGO 600+, and MGO 800+.
Finally, if you’re looking for the ultimate punch against bacteria and other pathogens, we suggest MGO 829+. This honey has superior levels of both antibacterial activity and medicinal properties. MGO 850+, MGO 900+, and MGO 950+ are among the most common grades in this range.
MGO, Antibacterial Properties, and the Growing Concern of Antibiotic Resistance
With growing concern over antibiotic resistance, the antibacterial properties of Manuka honey, largely attributable to MGO, have gained increased attention. MGO has shown a promising ability to deter biofilm formation — protective layers bacteria create around themselves to defend against potential threats like antibiotics and disinfectants. Because these biofilms prove difficult to penetrate and kill, they pose a significant challenge when treating wounds or infections with conventional medications.
In addition to fighting biofilms, MGO in Manuka honey has demonstrated potential in restricting the growth of dangerous pathogens. It’s proven effective against Streptococcus pyogenes, gram-negative bacteria including E. coli, and even hard-to-treat methicillin-resistant Staphylococcus aureus (MRSA).
Due to its higher concentration of methylglyoxal (MGO), Manuka honey is now considered a potential treatment for blepharitis. Furthermore, gastrointestinal pathogens and oral infections exhibit susceptibility to MGO.
What is the Highest MGO in Manuka Honey?
The True Honey Co.’s Rare Harvest Manuka Honey holds the highest grade ever sold worldwide, boasting an unmatched 2050+ MGO / 34+ UMF rating. This ultra-premium product has received independent certification, and is currently available for purchase. The company is accredited with a UMF® Honey Association Licence (#2900) and a FernMark Licence (No. 100086).
Manuka honey with a MGO value greater than 1,700 is difficult to find. Some manufacturers produce manuka honey with a higher MGO but it’s expensive and hard to source. New Zealand Honey Co., for example, sells its 1282+ variety online, Manukora sells its 1123+ variety on their website and also through Amazon, and Manuka Doctor sells its 1025+ variety on its website.
Final Note
In summary, MGO is a natural compound, mostly found in Manuka honey, highly regarded for its unique therapeutic and antibacterial properties. This magic ingredient, derived through an intriguing process involving bees and the Manuka flowers, significantly contributes to the overall potency of Manuka honey. While MGO concentration alone does not guarantee the authenticity or quality of Manuka honey, its measurement, combined with a UMF grading, provides a comprehensive evaluation system to ensure consumers receive genuine and quality honey. The remarkable therapeutic potential of MGO also underscores its invaluable role in combating medical challenges like antibiotic resistance, underscoring the manifold benefits and applications of Manuka honey.