What is MGO in Manuka honey? A Clear Guide

MGO in Manuka honey is methylglyoxal, a natural compound that develops from a nectar precursor called DHA, and it is the main reason Manuka honey carries a lab-tested grade instead of just the word "honey" on the label. MGO drives much of Manuka honey's signature antibacterial strength, and the higher the tested MGO number, the more of the compound is in the jar. The research on MGO itself is deeper in some areas than others: its antibacterial role in whole honey is well established, while claims about antioxidant, anti-inflammatory, or immune benefits from MGO specifically are still early and, in several cases, truly mixed. The table below lays out what the evidence supports for each property.

Key Takeaways

• MGO in Manuka honey is a naturally occurring compound that forms from a nectar-derived precursor, and it is why Manuka honey is lab-graded instead of simply called "honey"
• The MGO content of Manuka honey plays a major, well-documented part in its antibacterial strength, and honey with a higher lab-tested MGO number generally shows stronger antibacterial activity
• Commercial MGO grades, from MGO 30+ up to Biosota's independently tested MGO 2200+, reflect a guaranteed minimum concentration verified in a lab, not a marketing claim

What Is Methylglyoxal?

Methylglyoxal, or MGO from here on, is a small compound that occurs naturally in Manuka honey. It is one of the main reasons Manuka honey is graded in a lab instead of being sold as ordinary honey.

MGO in Manuka honey builds up by itself as the honey matures, starting from a nectar compound called DHA (covered in the next section). Nobody adds it, and it is not a marketing invention. Independent labs can measure the exact amount of MGO in a jar, in milligrams per kilogram, much like a food label lists protein or sugar. That measurable, verifiable number is what sets the Manuka grading system apart from a vague "premium" label.

Where Does MGO Come From?

The story of MGO in Manuka honey begins with DHA (dihydroxyacetone), a compound found naturally in the nectar of Leptospermum, the group of plants Manuka honey comes from. Australia has over 80 native Leptospermum species, and their nectar holds unusually high levels of DHA compared with most other flowers that bees visit.

As the honey matures and sits in storage, DHA slowly turns into MGO, with no enzyme or additive driving the reaction. That chemistry is not exclusive to Manuka nectar. Researchers have set off a similar reaction in the lab by adding DHA to ordinary clover honey. What sets Manuka honey apart is simply how much DHA its nectar contains to begin with.

Freshly harvested Manuka honey tends to hold more DHA and less MGO, while honey that has matured or been stored longer tends to hold more MGO and less DHA. This is part of why MGO in Manuka honey rises over time instead of sitting at a fixed level from day one.

Why MGO Matters

MGO in Manuka honey is the one compound most responsible for making it different from every other honey. A higher MGO number means stronger antibacterial strength, and that relationship is the defining feature of Manuka honey.

MGO is not the only thing Manuka honey may offer. Gut health, immune support, skin and wound care, and other areas each have their own body of evidence, all covered in Manuka Honey Benefits, our complete guide to what the research says about the many uses of Manuka honey. This page goes deep on MGO itself: what it is, how it is measured, what the evidence for its specific properties shows, and how to pick the right grade. To learn how Biosota reaches these strength levels in the first place, read How Biosota Produces the Highest MGO Manuka Honey in the World.

How Is MGO Measured?

The MGO level in Manuka honey is determined with standard laboratory chemistry, not estimated or self-reported. One common method converts MGO into a more stable compound that HPLC, a chromatography technique used throughout food science, can measure precisely. The result is reported in milligrams of MGO per kilogram of honey (mg/kg). Some labs use nuclear magnetic resonance instead, which measures MGO directly rather than through a converted compound.

Either way, the output is the same kind of number: an exact, repeatable measurement rather than a subjective grade. That is what lets an independent lab, and not the brand selling the honey, confirm what is actually in the jar.

MGO Ratings Explained

Commercial grading of MGO in Manuka honey follows a tiered system, and each number on a label is a guaranteed minimum, not an exact figure. A label reading MGO 250+ means the honey contains at least 250 mg/kg of MGO, confirmed by independent lab testing, and possibly more.

Biosota sorts the commonly used MGO grades into five bands:

You can see the full strength breakdown on our Manuka honey MGO chart.

Biosota's Australian Manuka honey is independently lab-tested across the full range, from MGO 150+ up to MGO 2200+. Every grade is exactly what it says: a verified minimum MGO concentration, not a marketing label. For a closer look at how these numbers translate into practical strength, see MGO: Why The Numbers Matter and Decoding Manuka Honey Ratings and Certifications.

Expert Insight

Dr. Peter Brooks, lead Manuka honey researcher at the University of the Sunshine Coast, describes methylglyoxal (MGO) as a practical way to gauge both the strength and the purity of Manuka honey.

In his view, the MGO rating shows how much Manuka activity a given honey carries. As the rating climbs, so does the concentration of beneficial compounds, phenolics included.

For shoppers, the MGO number works as a simple guide. Lower ratings, such as MGO 30+, may point to only a small share of Manuka honey, while higher ratings indicate a more concentrated and bioactive product.

Dr. Brooks also notes that once MGO levels reach around 260+, the honey starts to show a higher level of bioactivity. At very high levels, such as MGO 1200+ and above, the honey is an exceptionally concentrated form of Manuka, prized for its purity and strength.

Watch: What Does the MGO Number Mean in Manuka Honey

MGO vs NPA/ULF

MGO in Manuka honey is not the only rating system out there. NPA (Non-Peroxide Activity), also called ULF (Unique Leptospermum Factor), is a different kind of measurement and worth understanding on its own terms.

MGO is a chemical measurement that tells you exactly how much of one specific compound the honey contains. NPA is a functional measurement: it tests how strongly the whole honey inhibits bacteria in a lab assay, after the honey's separate hydrogen-peroxide-based antibacterial activity has been removed.

MGO is a strong predictor of a honey's NPA-type activity, but the two numbers are not interchangeable. MGO explains much, though not necessarily all, of a honey's real-world antibacterial performance, so an NPA figure calculated purely from an MGO reading is not the same as one obtained through direct, independent lab testing. Biosota reports MGO because it is the more precise, directly verifiable chemical measurement. For more on how NPA itself is defined and tested, see What Is NPA in Manuka Honey.

What Does MGO Do? Antibacterial Activity

This is where the evidence for MGO in Manuka honey is strongest.

In lab testing, purified MGO on its own inhibits bacteria including E. coli and S. aureus, among them antibiotic-resistant MRSA strains, and the effect grows stronger as the concentration rises. Bacteria sheltered inside a biofilm, the protective layer a bacterial colony builds around itself, need a higher MGO concentration than free-floating bacteria to show the same effect.

In whole Manuka honey, and not just isolated MGO, a higher MGO content is consistently tied to stronger antibacterial activity against S. aureus, including MRSA. Whole honey also regularly outperforms a synthetic solution matched to the same MGO concentration, which tells researchers that other compounds in the honey, besides MGO, are adding to its antibacterial strength.

There is an important limit here as well. The link between MGO and antibacterial activity is not the same for every bacterial species. A 2022 comparative study of commercial Manuka honeys found a strong correlation between MGO content and antibacterial activity against E. faecalis and E. coli, a moderate correlation against S. aureus, and no measurable correlation at all against Pseudomonas aeruginosa, a bacterium sometimes involved in wound infections. A high MGO number is a truly strong signal for some bacteria and simply does not predict performance for others. Treating an MGO grade as a universal potency score for every possible bacterium overstates what the research supports.

Methylglyoxal and Antioxidant Activity

Antioxidants help protect cells from a type of internal damage linked to aging and chronic disease. Manuka honey is sometimes said to have antioxidant properties, so it is fair to ask whether MGO in Manuka honey is the reason.

The direct evidence says no, at least for now. In a controlled lab test that compared the individual compounds in Manuka honey side by side, purified MGO showed no meaningful antioxidant activity, while a different compound found naturally in Manuka honey, methyl syringate, did far better on the same test. Whole Manuka honey does show measurable antioxidant activity in lab assays, and that activity does rise with potency grade, but the direct component testing points to other compounds, not MGO, as the source. None of this means Manuka honey lacks antioxidant activity. It means that particular activity should not be credited to MGO.

Methylglyoxal and Anti-Inflammatory Activity

Whether MGO in Manuka honey calms inflammation or adds to it depends heavily on which study you read, and that deserves a plain statement instead of quoting only the flattering half.

Several recent lab and animal studies using purified MGO report anti-inflammatory effects: less inflammatory signaling in cell models and better outcomes in certain animal disease models. Other peer-reviewed research on purified MGO found the opposite, with MGO made by activated immune cells setting off a pro-inflammatory response. Taken together, the effect of methylglyoxal on inflammation looks truly two-directional, shifting with concentration, cell type, and the specific biological situation instead of pointing consistently one way.

None of this research involved whole Manuka honey or human trials.

The honest summary: the anti-inflammatory reputation of methylglyoxal is not yet established science. It is an active and genuinely mixed area of research, not a confirmed benefit of Manuka honey.

Methylglyoxal and Immune Support

MGO in Manuka honey is sometimes marketed elsewhere as an immune booster. The actual research is thinner, and more mixed, than that framing suggests.

Studies using purified MGO report inconsistent effects on immune cells. Some found that MGO suppressed certain immune cell functions, while separate animal studies found that MGO raised immune cell activity instead. One lab study that used MGO derived from whole Manuka honey, rather than a synthetic version, found it activated a specific type of immune cell in a test-tube setting. That is an early mechanistic finding, not evidence of a clinical immune benefit from eating Manuka honey.

Put simply, there is no strong clinical evidence that Manuka honey or its MGO content works as a general immune-support supplement for otherwise healthy people. The research that exists is limited to lab, animal, and observational-diet studies, not human trials of Manuka honey itself. This is an area to watch, not a benefit to claim yet.

Is a Higher MGO Rating Always Better?

Not necessarily, and this comes down more to matching the honey to the use than to any settled research question. Independent, peer-reviewed research does not directly answer which MGO grade suits which purpose, so what follows is Biosota's own product guidance, not a scientific finding.

A higher rating for MGO in Manuka honey does mean a higher concentration of a compound that is more antibacterial, confirmed by lab testing (see the section above). But a bigger number is not automatically better for every use. For everyday, general wellbeing use, a mid-range grade is often the sensible, practical pick. Where antibacterial strength matters more, a higher grade may be the better fit. Choosing a grade is about matching strength to purpose, not reaching for the highest number on the shelf.

How to Choose the Right MGO Level

A practical approach: start with what you actually want the honey for, then match the grade to it, not the other way around.

• Everyday use and general wellbeing: a lower-to-mid grade, MGO 150+ to 550+, is a reasonable and cost-effective daily choice.
• Stronger antibacterial focus: mid-to-high grades, MGO 550+ to 1200+, fit situations where the stronger antibacterial evidence above matters most.
• Maximum strength: Biosota's MGO 1717+ and MGO 2200+ grades are the highest independently tested strengths available, meant for people who specifically want the top of the verified range.

Whichever grade of MGO in Manuka honey you pick, look for one thing above all: independent lab testing behind the number on the label. Browse Biosota's full independently lab-tested Manuka honey range, from MGO 150+ to MGO 2200+, and find the grade that fits your use.

What Does the Research Actually Say About MGO?

Pulling it together: MGO in Manuka honey has a well-supported role in antibacterial strength. Its role in antioxidant, anti-inflammatory, and immune properties specifically is not established, at least not yet.

The most important caveat across all of this is that the antibacterial link of MGO depends on the species. It correlates strongly with antibacterial activity against some bacteria, such as E. coli and E. faecalis, and only moderately against others, such as S. aureus, with no measurable correlation at all against Pseudomonas aeruginosa in the comparative research. A high MGO grade is a real strength signal, but not a universal one.

For antioxidant, anti-inflammatory, and immune activity, the honest position is that research on isolated MGO is early, model-specific, and in places contradictory, and none of it has been tested in a human clinical trial of Manuka honey itself. That is not a reason to dismiss MGO. It is a reason to be precise about what a high MGO number does, and does not yet, prove.

FAQs

What is MGO in Manuka honey?

MGO (methylglyoxal) is a naturally occurring compound that forms in Manuka honey from a nectar compound called DHA. It is independently lab-tested and reported in milligrams per kilogram, and it is the main reason Manuka honey is graded instead of sold as plain honey.

What are the benefits of methylglyoxal?

The best-supported role of MGO in Manuka honey is antibacterial. In lab testing it inhibits bacteria directly, and in whole Manuka honey a higher MGO content correlates with stronger antibacterial activity, though not equally against every bacterial species. Claims about its antioxidant, anti-inflammatory, or immune benefits specifically are still early research, not established findings.

Does methylglyoxal have antioxidant properties?

Not on its own, as far as is established. Direct lab testing of purified MGO found no meaningful antioxidant activity. The measurable antioxidant activity of Manuka honey comes from other compounds in the honey, not from MGO itself.

How does MGO affect Manuka honey?

MGO is what makes Manuka honey lab-graded and measurably different from other types of honey. It forms naturally during maturation, and the amount present, confirmed by independent testing, is what the MGO number on a label actually stands for.

Is a higher MGO rating always better?

Not automatically. A higher MGO grade means more of a compound that is genuinely antibacterial, but matching the grade to your actual use matters more than simply choosing the highest number available.

References

1. Waikato Research Commons, DHA-to-MGO conversion in Manuka honey during maturation. https://researchcommons.waikato.ac.nz/server/api/core/bitstreams/812d8da7-e8eb-4b99-8bd6-9cfe1d278ff6/content
2. Journal of Agricultural and Food Chemistry, DHA-spiked clover honey conversion demonstration. https://pubs.acs.org/doi/10.1021/jf404767b (preliminary, DHA-to-MGO chemistry demonstrated outside Manuka honey)
3. Journal of Agricultural and Food Chemistry, Manuka nectar DHA content. https://pubs.acs.org/doi/10.1021/acs.jafc.7b00797
4. Jervis-Bardy et al., methylglyoxal as active agent against bacterial biofilms. https://pubmed.ncbi.nlm.nih.gov/22287464/ (in vitro, isolated MGO, not whole honey)
5. Kwakman et al., antibacterial activity of Manuka honey and its components. https://pmc.ncbi.nlm.nih.gov/articles/PMC6613335/
6. Allcott et al., Manuka honey antimicrobial activity beyond sugar and MGO alone. https://eprints.worc.ac.uk/16509/
7. Roberts et al., methylglyoxal as a major contributor to Manuka honey's antibacterial activity. https://pubmed.ncbi.nlm.nih.gov/24860556/ (in vitro)
8. Comparative study of commercial Manuka/Leptospermum honeys, MGO correlation with antibacterial activity by bacterial species. https://pmc.ncbi.nlm.nih.gov/articles/PMC9333225/ (includes isolated-MGO MIC data, in vitro)
9. Albaridi, antibacterial potency of honey (review). https://pmc.ncbi.nlm.nih.gov/articles/PMC6589292/
10. Quantification of methylglyoxal in Manuka honey (analytical chemistry method). https://pmc.ncbi.nlm.nih.gov/articles/PMC10000891/
11. Commercial Manuka honey MGO, DHA and HMF measurement study. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0272376
12. Review of NPA and MGO's contribution to Manuka honey's antibacterial activity. https://pmc.ncbi.nlm.nih.gov/articles/PMC5193333/
13. Review of Manuka honey antibacterial and antibiofilm activity. https://pmc.ncbi.nlm.nih.gov/articles/PMC4837971/
14. MGO concentration and phenol-equivalence antibacterial assay in Leptospermum honey. https://pmc.ncbi.nlm.nih.gov/articles/PMC11111008/
15. O'Keeffe et al., component-level antioxidant testing of Manuka honey compounds. https://pure.ulster.ac.uk/en/publications/total-phenols-antioxidant-capacity-and-antibacterial-activity-of--4 (in vitro, isolated MGO showed no meaningful antioxidant activity)
16. Henderson et al., Manuka honey antioxidant capacity assay. https://doi.org/10.1016/j.foodchem.2014.11.009
17. Isolated methylglyoxal anti-inflammatory mechanism studies (NRF2/inflammasome pathways). https://pmc.ncbi.nlm.nih.gov/articles/PMC10440576/ ; https://pmc.ncbi.nlm.nih.gov/articles/PMC12888337/ (animal models, isolated MGO)
18. Prantner et al., macrophage-produced methylglyoxal triggers pro-inflammatory response. https://pubmed.ncbi.nlm.nih.gov/42234520/ (in vitro, isolated MGO)
19. Isolated methylglyoxal immune-suppressive and immune-stimulating animal studies. https://pmc.ncbi.nlm.nih.gov/articles/PMC3829040/ ; https://pubmed.ncbi.nlm.nih.gov/18617020/ (animal models, isolated MGO)
20. Manuka-honey-derived methylglyoxal and MAIT cell activation. https://pubs.rsc.org/en/content/articlehtml/2020/fo/d0fo01153c (in vitro)