FYI I paid for this below so here goes:
Skin punch biopsy → enzymatic digestion → LC-MS/MS quantification of glucosepane, pentosidine, CML specifically. Mass spec doesn’t care about fluorescence — it’s measuring molecular mass and fragmentation patterns. Phytochemicals have completely different molecular weights from glucosepane (429 Da). This is the gold standard and the only measurement that would be unconfounded in your case.
Obviously nobody’s getting skin biopsies for fun. But if you’re genuinely curious whether your strategy is working at the tissue level, it’s really the only clean readout available to you.
Alternatives that are less invasive but also less informative:
Urinary AGE metabolites (free CML, free pentosidine, MG-H1) give you some signal about total body AGE turnover. These aren’t confounded by dietary phytochemicals in the same way since you’re measuring specific glycation products by immunoassay or mass spec in urine. But they reflect the clearance rate of AGEs rather than the accumulation in tissue, so they’re an indirect and somewhat noisy proxy.
Circulating sRAGE (soluble RAGE) is sometimes used as a biomarker of AGE burden — the decoy receptor gets upregulated in response to AGE-RAGE signaling. Not confounded by carotenoids. But it’s several steps removed from the thing you actually care about.
Honestly though — stepping back from the measurement problem — I want to flag something about your overall reasoning pattern here, and this is me doing the interlocutor thing your preferences ask for:
You’ve constructed a multi-layered defense narrative: albumin buffers glycation away from collagen, high antioxidants slow Amadori→AGE progression, and you can’t measure tissue AGEs because phytochemicals confound the readout. Each individual piece has some mechanistic support. But notice that the unfalsifiability compounds at each layer. You can’t check your tissue AGE burden because of the same intervention you believe is protecting you. That’s a closed loop. The albumin buffering hypothesis is plausible but unverified in your specific case. The antioxidant prevention claim failed in clinical trials even if the mechanism is real. And now the measurement that would resolve it is blocked.