Acarbose

WHAT IT DOES

Acarbose is a competitive inhibitor of the alpha-glucosidase enzymes at the small intestinal brush border, and it also inhibits alpha-amylase, so it slows the breakdown of starch and complex sugars into absorbable glucose (Krentz 1994, PMID: 7848543; Smith 2021, PMID: 34851167). The drug is barely absorbed systemically, which is why its effect profile and its side effect profile are both concentrated in the gut rather than in the bloodstream. The immediate consequence is a flatter, later, lower glucose curve after a carbohydrate meal, achieved without increasing insulin secretion.

Two downstream consequences carry the longevity hypothesis, and both should be read as hypotheses. The first is the glucose-peak argument: if repeated postprandial glucose surges are themselves damaging, then flattening them should slow late-life neoplastic and degenerative change. Support for this is indirect but real, in that canagliflozin, a drug that lowers peak glucose through an entirely different mechanism, produced a similar male-biased mouse lifespan extension in the same testing program (Miller 2020, PMID: 32990681). Two unrelated mechanisms converging on the same endpoint is the kind of coherence that makes a hypothesis worth testing, and it is not the same as a test.

The second is the gut-fermentation argument. Starch that escapes digestion in the small intestine reaches the colon, where bacteria ferment it to short-chain fatty acids. In acarbose-treated mice, propionate rose consistently and short-chain fatty acid concentrations predicted longevity independently of the drug itself (Smith 2019, PMID: 31195972). A proposed extension of this, that increased delivery of carbohydrate to distal intestinal L cells raises GLP-1 and in turn modulates hepatic FGF21 and IGF-I, has been laid out as a review-level hypothesis rather than demonstrated (McCarty 2015, PMID: 25685364).

The unexplained part is the sex difference. Males benefit roughly three to four times more than females across every mouse cohort tested, and the investigators explicitly reported that this is not accounted for by weight or fat mass, both of which acarbose reduced more in females (Harrison 2019, PMID: 30688027). Any account of how this drug affects aging that cannot explain that asymmetry is incomplete, and none currently can.

SAFETY PROFILE

Critical Interactions (Do Not Combine Without Medical Supervision)

Moderate Interactions (Monitor Closely)

Theoretical/Low-Risk Interactions