C4 Sugars

C4 Sugars

This test is used internationally to detect whether honey has been adulterated by adding sugar (mainly cane sugar and high fructose corn syrup).

Sugars produced from tropical plants like sugar cane and maize/corn are produced using a photosynthetic pathway referred to as the C4 pathway. Nectar which is collected by bees comes from plants that use a different process of photosynthesis, referred to as the C3 pathway.

There is a measurable difference in the ratio of the naturally occurring carbon-12 and carbon-13 isotopes in sugars arising from the C3 and C4 pathways, and this test uses this difference to identify whether C4 sugar appears to have been added to the honey.

The test reports an apparent C4 sugar content, and there is an internationally accepted limit for apparent C4 sugar content (as measured by this test) of 7%.

In recent years it has been shown that mānuka honey can have an apparent C4 sugar test result that is higher than 7%, even when it is clear that no sugar has been added.  Ongoing research is being undertaken to investigate this, and perhaps identify an alternative way of detecting sugar adulteration.  In the meantime, this remains as an important test for access to some international markets.

Please note, this test is designed for pure honey only. Honey with organic additives (e.g. ginger, berries, etc.) are not suitable for this test.

Click here to read more about C4 Sugars in an article written by one of our technologists for The New Zealand Beekeeper Journal. 


Protein (mainly derived from pollen) is extracted from honey by precipitation, and is analysed for its carbon-12 to carbon-13 ratio.  The carbon-12 to carbon-13 ratio is also analysed in the whole honey, and the difference between the values for whole honey and protein is used to calculate the apparent C4 sugar content.

Analytica uses Isotope Ratio Mass Spectroscopy and Cavity Ringdown Spectroscopy to carry out this testing, conforming to the internationally recognised AOAC standard method.



The Screening Test is a simplified version of the AOAC reference method. While results are more variable, you still receive a good indication of what the test result would be if tested using the full method (AOAC).

At half the price of C4 AOAC method, the C4 Screen method is a cost-effective option, suited to testing honey at extraction, when buying or selling, and prior to blending. Note: This method may not be suitable for export.

Read more about our C4 Screening test here


A comprehensive test which fully conforms to the AOAC 998.12 standard. With less variable results than the C4 Screen method, it is recommended for use in final production or packed samples and will be preferred by those needing a higher level of precision and/or a certificate of analysis for export purposes.


Both the C4 Sugar AOAC and C4 Sugar Screen tests are IANZ accredited.


Routine 4 day TAT for C4 Sugar results. Please contact Analytica for current pricing on +64 7 974 4740 or at info-analytica@alsglobal.com


Analytica offers significantly reduced turnaround time, highly competitive prices, and strong client support.

Need Testing Services?

Let Us Know How We Can Help

We are fully committed to our timely customer service and are always happy to consider solutions to your unique testing needs including the potential for R&D.


Request A Quote

Tell us how can we help you