MGO and UMF: What Manuka Honey Activity Ratings Actually Measure

Manuka honey is honey produced by European honey bees foraging on the manuka tree (Leptospermum scoparium), native to New Zealand and parts of southeast Australia. What makes it commercially valuable is not the sugar content — that is similar to all honey — but a single small molecule called methylglyoxal (MGO) which manuka honey contains in concentrations 100 to 1,000 times higher than ordinary honey. MGO is the source of manuka's well-documented antibacterial activity.

The two rating systems

MGO (methylglyoxal) — the direct measurement

MGO is a number expressed in milligrams of methylglyoxal per kilogram of honey (mg/kg). It is measured directly in the laboratory by HPLC. A label of MGO 250 means 250 mg of methylglyoxal per kg of honey. MGO 850 means 850 mg/kg. The number scales linearly with antibacterial potency — MGO 250 is roughly half the antibacterial activity of MGO 500.

MGO is the rating system used most commonly by Australian and many international producers, and the simplest to understand: it is the chemistry, with no conversion needed.

UMF (Unique Manuka Factor) — the New Zealand certification scheme

UMF is a trademark and certification programme run by the Unique Manuka Factor Honey Association in New Zealand. A UMF rating tests for four markers: MGO (antibacterial), DHA (the precursor to MGO that converts over time, indicating freshness potential), leptosperin (a manuka authenticity marker), and HMF (a freshness marker — high HMF indicates heat damage or age). UMF certification therefore proves both potency AND authenticity AND quality.

The UMF number itself is benchmarked against the antibacterial activity of phenol — UMF 10+ honey has antibacterial activity equivalent to a 10% phenol solution. Higher UMF means higher activity.

Conversion table

Approximate conversion: MGO ≈ (UMF − 2) × 50. UMF 10+ ≈ MGO 400. The exact relationship is non-linear at the very high end.

How to choose what you actually need

For everyday food use

MGO 100–250 (UMF 5+ to 10+) is plenty. Higher grades have minimal extra benefit when consumed as honey on toast, and the price premium is significant. The flavour gets stronger and more medicinal as MGO climbs.

For sore throat, immune support during a cold

MGO 250–550 (UMF 10+ to 16+) hits the sweet spot. Take a teaspoon directly or in warm (not hot — heat above 60 °C destroys MGO) water with lemon. Two to three times daily.

For skincare formulations

Skincare formulators use MGO 400–550 (UMF 13+ to 16+) honey because it gives meaningful antibacterial activity while remaining affordable enough to use at 5–10% inclusion in finished products. Higher MGO honey is wasted in a wash-off product because contact time is short.

For genuine wound care

Medical-grade manuka honey for wound dressings — used in hospitals globally — is typically MGO 800+ (UMF 20+) and is gamma-irradiated to remove all viable bacterial spores. Do not self-treat serious wounds; this is a clinical decision.

Common pitfalls when buying manuka honey

• "Active manuka honey" with no MGO or UMF number on the label means nothing. Walk away.
• Total Activity (TA) ratings — measured with peroxide present — are not specific to manuka. Manuka's value is non-peroxide activity, which is what MGO captures.
• "Manuka blend" honey is a blend of manuka with cheaper honeys. The MGO will be diluted proportionally. Read the small print.
• A UMF certificate must show the licensee number and a current expiry. Old certificates from companies no longer in the program are not valid.
• Check the harvest year. MGO continues to convert from DHA over the first 6–12 months, and a fresher honey actually gains potency for a while; very old honey (3+ years) starts losing it.

How activity affects price

A rough international retail benchmark per 250 g jar:

Prices vary significantly by retailer and brand reputation — these are order-of-magnitude figures.

How it shows up in our portfolio

The Manumax range we carry uses MGO-active manuka honey across all SKUs. The Ice Soothing Spray, Shower Gel and Sheet Mask formulations target the MGO 400–550 range — high enough for meaningful antibacterial benefit at the inclusion rate used in cosmetic formulations, while keeping price points accessible. Manumax operates from New Zealand, which gives them direct access to UMFHA-certified raw honey supply.