Insulin sensitivity tracking — cheapest reasonable proxy

HbA1c is cheap (~$20 at most labs, sometimes pharmacy-run) and gives you 90-day average glycemia. Not IS per se but the best cheap proxy available.

CGM for 10 days at ~$80 gives you post-prandial excursion data which is IS-adjacent. Actionable within a cycle.

TG:HDL ratio from standard lipid panel is a decent IS proxy. Cheap because it's bundled.

Good suggestions. Probably going to use HbA1c + 10-day CGM as my standard IS tracking going forward.