What MGO 250+ actually means, and how to check it
MGO 250+ on a jar of Manuka honey means 250 milligrams of methylglyoxal per kilogram of honey, verified by laboratory analysis. It is one of the few numbers in the wellness aisle that means something precise and can be independently checked.
Where the number comes from
Manuka honey comes from the nectar of Leptospermum trees. That nectar contains a compound called dihydroxyacetone, and as the honey matures the dihydroxyacetone converts into methylglyoxal. No other honey does this in any quantity, which is why methylglyoxal is used as the marker for Manuka.
Because the conversion happens naturally and varies with the trees, the season and the site, every batch is different. So the grade is not a recipe. It is a measurement, taken after the fact, on that batch.
The correlation between methylglyoxal content and Manuka's distinctive non-peroxide activity is strong and well characterised. (Cokcetin et al., PLoS One, 2016, PMID 28030589.)
What 250+ is, in context
Grades run from about MGO 30 at the entry level to MGO 800 and beyond at the top, where the price climbs steeply.
Using the industry conversion tables, MGO 250+ sits at roughly the level most people know as UMF 10+. It is the point at which a honey is unambiguously in the graded Manuka category rather than at the bottom of it, without being in the collector's-item bracket. For a honey that is eaten every day rather than kept for special occasions, that is a sensible place to sit.
The plus sign matters too. It is a floor, not an average. MGO 250+ means the batch tested at 250 or above.
Can you trust the number
Mostly, yes, and there is research on exactly this question.
A study measured 29 commercial Manuka and Leptospermum honeys from Australia and New Zealand against what their labels claimed. The measured methylglyoxal matched the label claims, with what the authors described as mostly minor differences. (Green et al., PLoS One, 2022, PMID 35901185.)
That is unusual. Most numbers on a supplement label cannot be verified by anyone outside the company. This one can be, and it has been.
What to look for on a jar: the MGO figure itself, and whether the producer says the analysis is done per batch by an independent laboratory. A brand that tests every batch and says so is telling you something a brand quoting a single historic figure is not.
Australian Manuka is Manuka
This confuses people, so it is worth settling.
New Zealand attempted to register Manuka honey as a certification mark restricted to New Zealand honey. The United Kingdom Intellectual Property Office refused that application in December 2021. In May 2023 the Intellectual Property Office of New Zealand upheld the Australian Manuka Honey Association's opposition, finding the term descriptive rather than exclusive to one country.
The botany supports it. Australia has more than 80 Leptospermum species. In a study of 80 Australian Leptospermum honey samples, honeys from the Northern Rivers in New South Wales and Byfield in Queensland reached up to 1,100 mg/kg of methylglyoxal, and activity was stable across seven years of dark storage. (Cokcetin et al., 2016.)
In Australia, honey labelled as Manuka must also meet Food Standards Australia New Zealand Standard 2.8.2, which sets out what may be described as Manuka honey.
What MGO does not tell you
Two things, in the interests of being straight about it.
The grade describes the Manuka portion. If a product blends Manuka with other honey, the grade attaches to the Manuka in it, not to the blend as a whole. A well-labelled product will tell you the percentage.
And a higher grade is not automatically a better food. Beyond a point you are paying for rarity. For everyday eating, a verified mid grade from a producer who tests every batch is a better proposition than an unverified high one.
What to take from it
MGO 250+ is a measured, certifiable, per-batch number, sitting at roughly UMF 10+, on a honey that Australia produces legitimately and abundantly.
In a category full of unverifiable claims, it is a number you can actually check.