This page covers one part of the Cliff Mad Honey Safety Standard. For the full grayanotoxin concentration classification, see the grayanotoxin risk bands.
Medical disclaimer: This page is for educational purposes only and is not medical advice. Mad honey contains grayanotoxin, which can cause serious adverse effects.
Units, analytical methods and the terms that appear on a certificate of analysis are defined in the grayanotoxin glossary.
Key Takeaways
- A mad honey lab report measures grayanotoxin (GTX) in mg/kg, milligrams per kilogram of honey.
- The same number means very different real-world exposure depending on how much honey is consumed.
- Published clinical data documents adverse effects across a wide concentration range, with the most severe cases associated with honey above 30 mg/kg.
- EFSA’s 2023 risk assessment found that every concentration it assessed, from 0.1 mg/kg up to the 1 and 10 mg/kg measured in mad honeys, raised health concerns for acute toxicity.
- Higher mg/kg does not simply mean “stronger effect”. It means a given serving delivers more GTX, and the outcome also depends on the quantity consumed, the individual, and concurrent health factors.
Contents
What the mg/kg Unit Means
Grayanotoxin concentration in honey is expressed as mg/kg: milligrams of grayanotoxin per kilogram of honey. This is numerically the same as micrograms per gram (μg/g).
To translate a lab report number into an actual dose: Dose (mg) = Concentration (mg/kg) ÷ 1000 × Serving weight (g)
- 5 mg/kg honey, 20g serving = 0.1 mg GTX
- 20 mg/kg honey, 20g serving = 0.4 mg GTX
- 50 mg/kg honey, 20g serving = 1.0 mg GTX
EFSA’s reference point (BMDL10 from animal studies) is 15.3 μg/kg body weight. For a 70 kg adult, that is approximately 1.07 mg total GTX, a dose a single tablespoon of high-concentration mad honey can approach or exceed. A reference point is used to assess risk. It is not a safe dose. Separately, EFSA is 75% or more certain that a concentration of 0.05 mg/kg in honey (GTX I and III combined) is protective for all age groups against acute poisoning; that figure does not cover other grayananes or genotoxicity.
The Four Concentration Ranges Documented in Published Research
These ranges are drawn from published laboratory analyses and clinical case literature. They describe concentrations that have been studied and reported. They are not safety categories, and no concentration has been shown safe for everyone: EFSA’s 0.05 mg/kg figure, above, covers acute poisoning only.
Trace: Below 1 mg/kg (total GTX I + III)
Primarily associated with conventional honey from regions where Rhododendron species are present, which researchers call unintentional contamination. EFSA’s calculated protective concentration (0.05 mg/kg) sits within this band. No published case reports document adverse effects specifically attributable to honey in this range under typical serving sizes.
Low: 1–10 mg/kg (total GTX I + III)
Encompasses the lower end of concentrations measured in honey associated with mild adverse effects in published case reports. In one Turkish series, the honey eaten by 25 patients who became unwell ranged from 0.17 to 20.22 mg/kg of GTX I and up to 75.46 mg/kg of GTX III (Aygun et al. 2018). Mild symptoms at this range include dizziness, nausea, sweating, and hypersalivation. EFSA based its protective concentration on toddlers, who eat the most honey for their body weight, but found the data too limited to say whether children are more vulnerable.
Moderate: 10–30 mg/kg (total GTX I + III)
Encompasses mean GTX concentrations measured in honey consumed by patients presenting with confirmed mad honey intoxication in published Turkish and Nepalese case series. In a 2018 study by Aygun et al., the combined mean GTX concentration approached 36 mg/kg in intoxication cases. Documented adverse effects include bradycardia, hypotension, syncope, nausea, vomiting, dizziness, and, in some cases, altered consciousness. Most patients in published Turkish case series required intravenous atropine and fluids and were observed in hospital for 12–24 hours.
High: Above 30 mg/kg (total GTX I + III)
The upper documented range in commercial mad honey products. Laboratory analyses of Turkish commercial samples found GTX III concentrations reaching 68.754 mg/kg. Published case reports of severe intoxication, including complete AV block, profound bradycardia (heart rates below 40 bpm), and loss of consciousness, are predominantly associated with consumption in or above this range. Temporary cardiac pacing has been reported in three patients with asystole or complete heart block (Ullah et al. 2018), and no deaths were reported among the 1,199 cases reviewed by Silici and Atayoglu (2015).
These ranges map directly onto the four bands of the Cliff Mad Honey Safety Standard.
Why “Higher Concentration = Stronger Effect” Is an Oversimplification
The relationship between GTX concentration and clinical outcome is not linear. Serving size matters more than concentration alone: a person consuming 5g of 50 mg/kg honey receives the same GTX dose as a person consuming 25g of 10 mg/kg honey. Individual factors (body weight, age, cardiovascular baseline health, concurrent medications) all affect how a given GTX dose translates to physiological effect. The GTX I:III ratio and 20+ other grayanotoxin variants not captured by standard lab reports also contribute to biological activity.
How to Use a Concentration Figure Responsibly
A lab report concentration figure tells you: (1) how much GTX I and/or GTX III is present per kilogram; (2) how that compares to concentrations documented in clinical case literature; (3) what dose a given serving size delivers. It does not tell you whether that dose is safe for you specifically, what other GTX variants may be present, or how that dose interacts with any medications you take.
Sources
- Aygun A, Sahin A, Karaca Y, et al. (2018). Grayanotoxin levels in blood, urine and honey and their association with clinical status in patients with mad honey intoxication. Turkish Journal of Emergency Medicine, 18(1), 29–33. doi:10.1016/j.tjem.2017.05.001
- Demir H, Denizbasi A, Onur O. (2011). Mad honey intoxication: a case series of 21 patients. ISRN Toxicology. PMC3658790. doi:10.5402/2011/526426
- Eroğlu SE, Urgan O, Onur OE, et al. (2013). Grayanotoxin (mad honey): ongoing consumption after poisoning. Balkan Medical Journal. PMC4115918. doi:10.5152/balkanmedj.2013.8100
- EFSA CONTAM Panel (2023). Risks for human health related to the presence of grayanotoxins in certain honey. EFSA Journal, 21(3), e7866. doi:10.2903/j.efsa.2023.7866
- Sahin H, Turumtay EA, Yildiz O, Kolayli S. (2015). Grayanotoxin-III detection and antioxidant activity of mad honey. International Journal of Food Properties, 18(12), 2665–2674. doi:10.1080/10942912.2014.999866
- Jansen SA, et al. (2012). Grayanotoxin poisoning: ‘mad honey disease’ and beyond. Cardiovascular Toxicology, 12(3), 208–215. doi:10.1007/s12012-012-9162-2
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