What Is MGO in Manuka Honey? The Key to Its Potency

MGO in Manuka honey is the natural compound, methylglyoxal, that forms from a nectar-derived precursor called DHA, and it's the primary reason Manuka honey is graded rather than simply labelled "honey." It's directly responsible for much of Manuka honey's distinctive antibacterial strength, and the higher the lab-tested MGO number, the more of the compound the honey contains. Research on MGO itself is more developed 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, genuinely mixed. The table below sets out what the evidence actually supports for each property.

Key Takeaways

• MGO in Manuka honey is a naturally occurring compound that forms from a nectar-derived precursor, and it's the reason Manuka honey is lab-graded rather than simply labelled "honey"
• Manuka honey's MGO content plays a major, well-documented role 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, lab-verified concentration, not a marketing claim

What Is Methylglyoxal?

Methylglyoxal, MGO for short from here on, is a small, naturally occurring compound found in Manuka honey. It's one of the main reasons Manuka honey is lab-graded rather than simply sold as honey.

MGO in Manuka honey forms on its own during the honey's natural maturation, from a nectar compound called DHA (more on that below). It isn't added, and it isn't a marketing invention. Independent laboratories can measure the exact amount of MGO in a jar, in milligrams per kilogram, the same way a food label states protein or sugar content. That measurable, verifiable number is what separates Manuka honey's grading system from a vague "premium" label.

Where Does MGO Come From?

The story of MGO in Manuka honey starts with DHA (dihydroxyacetone), a compound naturally present in the nectar of Leptospermum, the group of plants Manuka honey comes from. Australia has over 80 native Leptospermum species, and DHA is unusually abundant in their nectar compared with the nectar of most other flowering plants bees visit.

As honey matures and is stored, DHA slowly converts into MGO, without any enzyme or additive driving the reaction. This conversion isn't exclusive to Manuka nectar chemistry itself. Researchers have reproduced a similar reaction by adding DHA to ordinary clover honey under lab conditions. What makes Manuka honey different is simply how much DHA its nectar naturally contains to begin with.

Freshly harvested Manuka honey tends to have more DHA and less MGO. Honey that has matured or been stored longer tends to have more MGO and less DHA. That's part of why MGO in Manuka honey climbs during maturation rather than being present at a fixed amount from day one.

Why MGO Matters

MGO in Manuka honey is the single compound most responsible for making it different from any other honey. The higher the MGO number, the stronger the antibacterial strength, and that relationship is Manuka honey's defining differentiator.

MGO isn't the only thing Manuka honey may offer. Gut health, immune support, skin and wound care, and other benefit areas each have their own evidence base, covered in full in Manuka Honey Benefits, our complete guide to what the research says across all of Manuka honey's uses. This page goes deep on MGO itself: what it is, how it's measured, what the evidence for its specific properties actually shows, and how to choose the right grade. For more on how Biosota reaches these strength levels in the first place, see How Biosota Produces the Highest MGO Manuka Honey in the World.

How Is MGO Measured?

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

Either way, the result is the same kind of number: an exact, repeatable measurement, not a subjective grade. This is what allows an independent lab, not the brand selling the honey, to confirm what's actually in the jar.

MGO Ratings Explained

Commercial grading of MGO in Manuka honey follows a tiered system, and every number on a label represents a guaranteed minimum, not an exact promise. An MGO 250+ label means the honey contains at least 250 mg/kg of MGO, verified by independent lab testing, possibly more.

Biosota groups the commonly used MGO grades into five bands:

• MGO 30+ to 250+: entry-level, general wellbeing use
• MGO 260+ to 490+: minimum medicinal-strength threshold
• MGO 500+ to 990+: higher medicinal strength
• MGO 1000+ to 1900+: superior strength
• MGO 2200+: the rarest, highest independently tested strength available, Biosota's own top grade

Biosota's Australian Manuka honey is independently lab-tested across the full range, from MGO 150+ up to MGO 2200+. Each grade is exactly what it claims to be: 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, explains that methylglyoxal (MGO) provides a practical way to understand both the strength and purity of Manuka honey.

Accordingly, the MGO rating reflects how much Manuka activity is present in a given honey. As the rating increases, so too does the concentration of beneficial compounds, including phenolics.

From a consumer perspective, the MGO number offers a simple guide. Lower ratings, such as MGO 30+, may indicate only a small proportion of Manuka honey, while higher ratings reflect a more concentrated and bioactive product.

Dr Brooks also highlights that once MGO levels reach around 260+, the honey begins to demonstrate a higher level of bioactivity. At very high levels, such as MGO 1200+ and above, the honey represents an exceptionally concentrated form of Manuka, valued for its purity and strength.

Watch: What Does the MGO Number Mean in Manuka Honey

MGO vs NPA/ULF

MGO in Manuka honey isn't the only rating system in this world. NPA (Non-Peroxide Activity), also called ULF (Unique Leptospermum Factor), is a different kind of measurement, worth understanding as a separate thing.

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

MGO is a strong predictor of a honey's NPA-type activity, but the two numbers aren't interchangeable. MGO explains much, but not necessarily all, of a honey's real-world antibacterial performance, so an NPA figure calculated purely from an MGO reading isn't the same as an NPA figure obtained through direct, independent lab testing. Biosota reports MGO because it's 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, including antibiotic-resistant MRSA strains, and the effect gets stronger as the concentration increases. Bacteria protected inside a biofilm, a bacterial colony's protective layer, need a higher MGO concentration than free-floating bacteria to see the same effect.

In whole Manuka honey, not just isolated MGO, higher MGO content is consistently linked to stronger antibacterial activity against S. aureus, including MRSA. But whole honey regularly outperforms an MGO-matched synthetic solution at the same concentration, which tells researchers that other compounds in the honey, not MGO alone, are also contributing to its antibacterial strength.

There's an important limit here too. MGO's link to antibacterial activity isn't 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 genuinely strong signal for some bacteria, and simply doesn't predict performance for others. Reading 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 kind of internal damage linked to aging and chronic disease. Manuka honey is sometimes described as having antioxidant properties, so it's a fair question whether MGO in Manuka honey is the reason.

The direct evidence says no, at least not yet. In a controlled lab test comparing Manuka honey's individual compounds side by side, purified MGO showed no meaningful antioxidant activity, while a different compound naturally found in Manuka honey, methyl syringate, performed far better on the same test. Whole Manuka honey does show measurable antioxidant activity in lab assays, and that activity does track with honey 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 specific activity shouldn't be credited to MGO.

Methylglyoxal and Anti-Inflammatory Activity

Whether MGO in Manuka honey calms inflammation or contributes to it depends heavily on which study you're reading, and that's worth saying plainly rather than picking the flattering half.

Several recent lab and animal studies using purified MGO report anti-inflammatory effects: reduced inflammatory signalling in cell models, and improved outcomes in specific animal disease models. Other peer-reviewed research on purified MGO found the opposite: MGO produced by activated immune cells triggered a pro-inflammatory response instead. Taken together, methylglyoxal's effect on inflammation looks genuinely two-directional, depending on concentration, cell type, and the specific biological situation, not consistently one thing or the other.

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

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

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 MGO suppressed certain immune cell functions, while separate animal studies found MGO increased immune cell activity instead. One lab study using 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's 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. What research 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 is genuinely more a matter of matching the honey to the use case than a research question with a settled answer. Independent, peer-reviewed research doesn't 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 genuinely more antibacterial compound, verified by lab testing (see the section above). But a higher number isn't automatically better for every use. For everyday, general wellbeing use, a mid-range grade is often the sensible, practical choice. For a use case where antibacterial strength specifically matters more, a higher grade may be the more appropriate pick. Choosing a grade is about matching strength to purpose, not defaulting to the highest number available.

How to Choose the Right MGO Level

A practical way to think about it: start with what you actually want the honey for, then match the grade, rather than the other way around.

• Everyday use, general wellbeing: a lower-to-mid grade, MGO 150+ to 550+, is a reasonable, cost-effective everyday choice.
• Higher antibacterial focus: mid-to-high grades, MGO 550+ to 1200+, suit situations where the stronger antibacterial evidence above is most relevant.
• Maximum strength: Biosota's MGO 1717+ and MGO 2200+ grades are the highest independently tested strengths available, reserved for those specifically seeking the top of the verified range.

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

What Does the Research Actually Say About MGO?

Pulling this together: MGO in Manuka honey plays 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 single most important caveat across all of this is that MGO's antibacterial link is species dependent. 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 genuine strength signal, not a universal one.

For antioxidant, anti-inflammatory, and immune activity, the honest position is that isolated MGO's research 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's not a reason to dismiss MGO. It's a reason to be precise about what a high MGO number does, and doesn't 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's independently lab-tested and reported in milligrams per kilogram, and it's the primary reason Manuka honey is graded rather than 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, 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 established on its own. Direct lab testing of purified MGO found no meaningful antioxidant activity. Manuka honey's measurable antioxidant activity 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 honey types. It forms naturally during maturation, and the amount present, verified by independent testing, is what the MGO number on a label actually represents.

Is a higher MGO rating always better?

Not automatically. A higher MGO grade means more of a genuinely antibacterial compound, but matching the grade to your actual use case 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)