Does GlycanAge measure glycation?

No, GlycanAge doesn't measure glycation. Instead, it measures glycosylation. Glycation happens when glucose attach to proteins as a random chemical process, while glycosylation is a highly regulated process that adds a specific type of sugar to a specific part of a protein during protein synthesis.
Sometimes, different types of sugars can be added to the same part of a protein. This is like how different words can be spelled with the same letters, or how people with different eye colours can have the same vision. This variation in sugar types is a bit like how genetic mutations can create different versions of genes. But with sugar structures, this variation is inherited from multiple genes, not just one.