Acarbose, a prescription oral medication for type 2 diabetes, slows starch and sugar digestion, blunting post-meal rises in blood sugar and insulin. In prediabetes, it delays diabetes onset; with normal blood sugar, benefits are smaller, less certain. Heart-attack prevention is unconfirmed. Longer life is shown only in mice, mainly males. Gas, bloating and loose stools are common; liver injury is rare. Meal-timed dosing, slow increases and liver tests are central. (Full Review)

Protocol

Label regimen

25 mg three times daily

Start dose; maximum 50 mg three times daily up to 60 kg, 100 mg three times daily above 60 kg

Diabetes-prevention trial regimens

50–100 mg three times daily

ACE used 50 mg, STOP-NIDDM 100 mg; both delayed diabetes; the lower dose suits tolerability

Timing

With the first bite

Of a carbohydrate-containing meal; no preferred time of day; skipped for meals without starch or sugar

Time to effect

Diabetes delay

Years

Seen in trials in prediabetes; lasts only while taken

Post-meal glucose

From the first dose

Stopping removes the effect within a day

HbA1c

4–6 months

Measured in label trials; lowering shown only in diabetes

Benefits

High: Delayed onset of type 2 diabetes in prediabetes; lower post-meal glucose, insulin and glycated hemoglobin

Medium: Fewer new cases of high blood pressure; lower triglycerides and total cholesterol; less post-meal blood pressure drop in older adults; lower colorectal and gastric cancer incidence; modest weight loss

Low: Fewer cardiovascular events; lower androgen levels in polycystic ovary syndrome; prevention of low blood sugar after gastric bypass

Speculative: Longer lifespan and healthspan in mice; increased colonic butyrate production; lower inflammatory markers

Contraindications

Known hypersensitivity to acarbose

Diabetic ketoacidosis or cirrhosis

Inflammatory bowel disease, colonic ulceration, partial intestinal obstruction or predisposition to obstruction

Chronic intestinal disease with marked digestion or absorption disorders, or conditions worsened by intestinal gas

Significant renal dysfunction (serum creatinine >2.0 mg/dL): use not recommended

Breastfeeding women

Pregnancy without clear need

Key Interactions

Insulin and sulfonylureas (glyburide): additive glucose lowering raises hypoglycemia risk

Digoxin: reduced absorption

Warfarin: probable rise in INR

Anticholinergic drugs (diphenhydramine): paralytic ileus reported

Activated charcoal and digestive enzymes (pancreatin; over-the-counter): reduce acarbose's effect

Alpha-galactosidase (Beano, over-the-counter): partly blunted acarbose's glucose-lowering effect

Drugs that raise blood sugar: thiazides (hydrochlorothiazide), corticosteroids (prednisone), thyroid hormone (levothyroxine), estrogens (estradiol), niacin and phenytoin may impair glucose control

Colestyramine (cholestyramine) and oral neomycin: may enhance acarbose's effects

Orlistat: added acarbose increased weight loss

Rosiglitazone: small, clinically insignificant fall in exposure

Theoretical (inferred from mechanism)

Carbohydrate-blocking supplements (berberine): additive glucose lowering; likely more gas and diarrhea

GLP-1 receptor agonists (semaglutide) and SGLT2 inhibitors (empagliflozin): additive glucose lowering

Fermentable fibers and sugar alcohols (inulin, sorbitol), lactulose: increased flatulence and diarrhea

Other oral antibiotics (rifaximin): could change acarbose's gut metabolism and gas production

Rapamycin (sirolimus): acarbose may partly offset rapamycin's rise in blood glucose

Risk & Side Effects

High: Flatulence, diarrhea and abdominal discomfort

Medium: Small hematocrit reduction and anemia

Low: Liver enzyme elevation and rare drug-induced hepatitis; hypoglycemia when combined with insulin or sulfonylureas; pneumatosis cystoides intestinalis and ileus; hypersensitivity skin reactions, edema and thrombocytopenia

Speculative: Shifts in gut bacterial communities

Monitoring

Marker	Target	Why
ALT and AST	Within laboratory normal limits	Safety check: elevations reduce or stop use
Serum creatinine / eGFR	Creatinine within laboratory normal limits	Safety check: use not recommended above 2.0 mg/dL
HbA1c	4–6%	Long-term glucose effect
Post-meal glucose (CGM or 1-hour finger-stick)	No established target; track the drop from the individual's own baseline on a repeated test meal	Primary pharmacological effect
Fasting glucose	70–99 mg/dL	Expected to change modestly
Fasting triglycerides	<150 mg/dL	Expected to change: modest reduction
Complete blood count (platelets, hematocrit)	Within laboratory normal limits	Safety check: rare thrombocytopenia; small hematocrit falls

Cadence: Baseline before starting; CGM or one-hour post-meal glucose during titration over the first 4–8 weeks; ALT and AST every 3 months in the first year, then periodically, commonly every 6–12 months; HbA1c, fasting glucose and triglycerides at 3 months, then every 6–12 months; creatinine and blood count yearly

Qualitative Assessment

Digestive tolerance: frequency and severity of flatulence, bloating and stool changes, ideally in a symptom diary during titration
Red-flag bowel symptoms: rectal bleeding, mucus, severe distension or constipation
Post-meal energy and drowsiness after carbohydrate-rich meals
Hypoglycemia symptoms (shakiness, sweating, confusion) when insulin or sulfonylureas are also used
Body weight trend

Acarbose for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment