Raw Honey Guide
Reference table · UMFHA tier ladder · 26 rows

UMF vs MGO: the decoder

The UMF Honey Association publishes a 26-row tier ladder mapping every UMF rating to a minimum methylglyoxal concentration in mg/kg. Here it is in one place, decoded for buyers, with an interactive converter, the band each tier sits in (entry / table / therapeutic / premium / clinical / ultra), and a clear explanation of why KFactor is not on this ladder at all.

The relationship is published, non-linear, and unambiguous: UMF 5+ floors at MGO 83, UMF 10+ at MGO 263, UMF 15+ at MGO 514, UMF 20+ at MGO 829, UMF 25+ at MGO 1200. Everything in between sits on a curve, not a straight line.

Last updated · companion blog at /blog/manuka-honey-grading-systems-explained

UMF 5+ floor
MGO 83
entry / authenticity
Therapeutic threshold
UMF 10+
MGO 263 mg/kg
UMF 25+ floor
MGO 1200
≈14× the entry band
UMF→MGO multiplier
non-linear
use the published ladder

Interactive converter

Move the slider to the UMF rating on a jar. The MGO floor, band, and buyer-level meaning come straight from the published ladder.

UMF rating
UMF 10+
MGO floor
263
mg/kg methylglyoxal
Band
Therapeutic

The conventional therapeutic minimum. Sore throat, immune support.

Three systems, three different things

Buyer confusion almost always traces to one of these three labels being treated as if it were the same as another. They are not. Each measures a different thing, on a different scale, certified by a different body.

UMF

Unique Manuka Factor

Custodian: UMF Honey Association (NZ, est. 1998)

Measures: A four-marker authenticity profile: methylglyoxal (MGO), leptosperin (botanical fingerprint unique to Leptospermum nectar), DHA (the precursor to MGO), and HMF (a freshness/heat-damage indicator).

Scale: The number is calibrated against a 1972 phenol-disinfectant equivalence test — UMF 10+ means non-peroxide antibacterial activity equivalent to a 10% phenol solution.

Strength: The only system that bundles authenticity (leptosperin), potency (MGO), maturity (DHA), and freshness (HMF) into one number.

Weakness: Licensing fee is significant; some genuine producers opt out and report MGO directly.

MGO

Methylglyoxal in mg/kg

Custodian: No central body — direct chemical assay

Measures: A direct lab measurement of methylglyoxal concentration in the honey, expressed in milligrams per kilogram. MGO is the compound responsible for Manuka's non-peroxide antibacterial activity.

Scale: Linear chemical concentration. Higher MGO = more methylglyoxal, period. No phenol-equivalence translation involved.

Strength: Unambiguous. Any accredited lab can verify any MGO claim. Adams et al. 2008 / Mavric et al. 2008 established that MGO drives the antibacterial activity in NZ Manuka.

Weakness: MGO alone does not authenticate the honey as Leptospermum-derived — leptosperin or pollen analysis is needed for that.

KFactor

Wedderspoon proprietary index

Custodian: Wedderspoon Organic Inc.

Measures: A pollen-count and total-activity index, not a methylglyoxal measurement. KFactor 12 / 16 / 22 indicate the percentage of Manuka pollen in the jar plus general antibacterial activity.

Scale: Proprietary scale — does not map to UMF or MGO ladders and is not licensable across producers.

Strength: The label explicitly does not require non-peroxide / methylglyoxal certification, which makes the honey cheaper to produce and ship.

Weakness: Pollen count is a botanical-presence test, not an antibacterial-activity test. A jar can satisfy a pollen threshold without containing therapeutic-band MGO. The brand was the subject of a 2018 U.S. class-action settlement that tightened how the rating could be marketed.

The full UMFHA tier ladder

Every tier in the published UMFHA ladder, with the methylglyoxal floor in mg/kg and the buyer-level meaning of each band. Bands shade from entry (light) to ultra-rare (deep).

UMFMGO floor (mg/kg)BandWhat this rating means for buyers
UMF 5+83EntryVerified Manuka, minimum certifiable activity. Daily table use.
UMF 6+117EntrySlightly above floor. Same use case as UMF 5+.
UMF 7+159TableMild antibacterial activity above peroxide-only honey baseline.
UMF 8+200TableApproximate cross-over with UMF's 1972 phenol-equivalent reference.
UMF 9+240TableApproaching therapeutic threshold but still in everyday use band.
UMF 10+263TherapeuticThe conventional therapeutic minimum. Sore throat, immune support.
UMF 11+311TherapeuticModest step above 10+. Same buyer use case.
UMF 12+356TherapeuticMid-therapeutic band. Many wound-care studies use this floor.
UMF 13+405TherapeuticAbove the in-vitro inhibitory concentration for S. aureus in most studies.
UMF 14+458TherapeuticApproaches the premium band. Activity ~3× UMF 5+.
UMF 15+514PremiumPremium therapeutic. Often the band marketed for medicinal kits.
UMF 16+572PremiumStep within premium. Diminishing buyer-noticeable returns.
UMF 17+633PremiumStep within premium. Common ceiling for retail wellness aisle.
UMF 18+696PremiumUpper premium. Typically gift-tier pricing per 250 g jar.
UMF 19+761PremiumApproaching clinical band. Mavric et al. 2008 ceiling for typical NZ Manuka.
UMF 20+829ClinicalClinical-grade. Used in some hospital wound-care formulations.
UMF 21+899ClinicalStep within clinical. Very limited shelf availability.
UMF 22+971ClinicalStep within clinical. ~12× the entry band activity.
UMF 23+1046ClinicalApproaches ultra band. Limited bee-yard windows produce this.
UMF 24+1122ClinicalApproaches ultra band. Mostly direct-from-producer channels.
UMF 25+1200Ultra-rareUltra-premium. Often >$200 per 250 g jar.
UMF 26+1281Ultra-rareStep within ultra. Diminishing buyer returns above UMF 25+.
UMF 27+1365Ultra-rareStep within ultra. Limited certification batches per year.
UMF 28+1450Ultra-rareStep within ultra. Auction-tier specialty product.
UMF 29+1538Ultra-rareStep within ultra. Single-batch vintage labels.
UMF 30+1628Ultra-rareTop of published ladder. Rare; investment / collector tier.

Source: UMF Honey Association published tier ladder (umf.org.nz). Methylglyoxal as the bioactive driver established by Adams et al. 2008 (J. Carbohydr. Res.) and Atrott & Henle 2009 (Czech J. Food Sci.). Typical NZ Manuka MGO range 38–761 mg/kg from Mavric et al. 2008 (Mol. Nutr. Food Res.); higher MGO values exist but are rarer.

Why KFactor is not on this ladder

KFactor is a Wedderspoon-proprietary index. The number primarily reports the percentage of Manuka pollen present in the jar, plus a general antibacterial test reported as Total Activity (TA). Both UMF and MGO ratings, in contrast, report the non-peroxide antibacterial activity that comes specifically from methylglyoxal — the bioactive Manuka chemistry.

Pollen presence is a good botanical-source signal: bees foraged on Manuka flowers. But pollen presence is not an antibacterial-activity measurement. A jar can satisfy a KFactor pollen threshold without necessarily containing therapeutic-band MGO.

A 2018 U.S. class-action settlement against Wedderspoon required the company to clarify that KFactor is not equivalent to UMF or MGO and to revise its marketing. Product labeled KFactor 16 — without a co-stated MGO value — cannot be placed on the published UMFHA tier ladder. Cross-checking the jar for an explicit MGO mg/kg figure is the simplest way to compare against UMF.

How to read a Manuka jar in under 30 seconds

  1. Look for UMF or MGO first. Either is a measurable, verifiable rating. KFactor alone is not.
  2. Cross-check on the ladder above. If the jar shows MGO 514 but no UMF, the equivalent UMF tier is 15+. If it shows UMF 10+ but no MGO, the equivalent MGO floor is 263.
  3. Decide which band you actually need. Daily wellness use sits comfortably in the table-to-therapeutic band (UMF 5+ to UMF 15+). Wound-care or clinical applications typically start at the premium band (UMF 15+) or higher.
  4. Check NZ origin if it matters to you. Australian Leptospermum honey can carry MGO ratings but is a different category. Most UMF-licensed jars are NZ-origin per the UMFHA license terms.
  5. If KFactor is the only marker, ask for an MGO test report. Genuine producers can supply an independent MGO assay on request.

Frequently asked questions

What is the simplest way to convert UMF to MGO?
Use the official UMFHA-published tier ladder. UMF 5+ = MGO 83+, UMF 10+ = MGO 263+, UMF 15+ = MGO 514+, UMF 20+ = MGO 829+, UMF 25+ = MGO 1200+. The relationship is non-linear; do not interpolate by simple multiplication. Whenever a jar shows one rating but not the other, the published ladder is the best reference.
Why is the UMF→MGO relationship non-linear?
UMF was designed in the 1990s as an equivalence rating against phenol disinfectant (a 10% phenol solution killed bacteria as effectively as a UMF 10+ honey). Methylglyoxal — discovered as the active driver in 2008 by Adams and colleagues — accumulates in honey via dihydroxyacetone (DHA) conversion, which is a kinetic process. The chemistry of phenol equivalence and MGO accumulation do not produce a straight line. They produce the curved ladder UMFHA publishes.
Is UMF 10+ the actual therapeutic threshold?
The convention in the wellness market is yes — UMF 10+ / MGO 263+ is widely treated as the buyer-side floor for therapeutic use. Peer-reviewed wound-care work (Cooper, Carter and Molan among others) typically used Manuka samples with non-peroxide activity equivalent to or above this floor, and most NZ-export-licensed therapeutic Manuka starts at UMF 10+. Lower tiers verify authenticity but offer modest activity above ordinary peroxide-only honey.
Why is KFactor not the same as UMF or MGO?
KFactor is a Wedderspoon-proprietary index that primarily reports the percentage of Manuka pollen in the jar, plus a general "Total Activity" antibacterial test. Pollen presence is a botanical-source signal (the bees foraged on Manuka), but it is not a methylglyoxal measurement. KFactor 16 does not equal UMF 16+ or MGO 263. A 2018 U.S. class-action settlement specifically required Wedderspoon to clarify that KFactor is not equivalent to UMF or MGO; honey labeled KFactor without a co-stated MGO value cannot be placed on the UMFHA ladder.
Does a higher UMF jar work proportionally better for sore throat?
In a strict in-vitro sense, antibacterial activity scales with MGO. In real consumer use the marginal benefit between, say, UMF 15+ and UMF 20+ for an everyday sore throat is small while the price difference is large. For sore throat, immune support and food use, UMF 10+ to UMF 15+ is the practical sweet spot. UMF 20+ and above are typically chosen for specific wound-care or clinical-formulation contexts. This is general information, not medical advice — consult a clinician for treatment decisions.
Why do some authentic Manuka producers report only MGO without UMF?
UMF licensing carries an annual cost and a four-marker testing protocol. Some producers prefer to publish a direct MGO number (which any accredited food lab can verify) and skip the UMF licensing fee. Their honey can be entirely genuine — the MGO assay alone is unambiguous. The trade-off is that without a UMF mark, leptosperin (botanical authenticity) is not certified by an external body. Cross-checking a producer's independent test report is the practical solution.
How does Manuka's antibacterial activity compare to ordinary raw honey?
Most raw honey has antibacterial activity from glucose oxidase producing low levels of hydrogen peroxide (H₂O₂) on dilution with wound exudate. That peroxide activity is real but is degraded by tissue catalase and by storage. Manuka's methylglyoxal activity is non-peroxide — it persists in the presence of catalase, so it remains active in wound environments where peroxide-only honeys lose much of their activity. Above MGO 263 / UMF 10+, the non-peroxide activity is large enough to be clinically distinguishable from ordinary raw honey.
Where do these MGO numbers come from for the ladder?
The UMF Honey Association publishes the complete tier ladder on its website (umf.org.nz). The numbers used here are those published thresholds. The chemistry behind the ladder traces to Adams et al. 2008 (J. Carbohydrate Research, identification of MGO as the bioactive marker), Atrott & Henle 2009 (Czech J. Food Sci., MGO–antibacterial activity correlation), and Mavric et al. 2008 (Mol. Nutr. Food Res., MGO concentration range 38–761 mg/kg in NZ Manuka).
What is leptosperin and why does UMF require it?
Leptosperin is a glycoside that occurs naturally and almost exclusively in nectar from Leptospermum (Manuka) flowers. Detecting leptosperin in a jar of honey is strong evidence the honey is genuinely Leptospermum-derived rather than a non-Manuka honey spiked with synthetic MGO. The UMF four-marker profile requires a minimum leptosperin reading at every tier — that is the authenticity check that pure MGO assays cannot provide on their own.
Should I pay for UMF 25+ rather than UMF 15+?
For most buyers, no. Above UMF 15+ the price scales steeply but the buyer-noticeable difference for everyday wellness use is small. UMF 20+ and 25+ make sense if you are using the honey in a wound-care protocol, if you have been advised by a clinician to use a high-MGO product, or if you are buying as a gift where the visible tier matters. For ordinary table and immune-support use, UMF 10+ to 15+ is where the price-to-activity curve is best.

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