Acarbose
Acarbose (Precose, Glucobay) is an alpha-glucosidase inhibitor that slows intestinal carbohydrate digestion, blunting post-meal glucose and insulin spikes. Bodybuilders use it to reduce fat gain from high-carbohydrate meals. It does not cause hypoglycaemia alone; its main drawback is prominent gastrointestinal gas and bloating.
01 Overview
Acarbose competitively inhibits intestinal alpha-glucosidase enzymes, delaying breakdown of complex carbohydrates and sucrose so glucose is absorbed more slowly and lower down the gut. It is an approved antidiabetic and has data suggesting cardiovascular benefit and even longevity signals in animals.
Physique users take it before carb-heavy meals to flatten glucose and insulin excursions and limit fat storage. Because undigested carbohydrate reaches the colon, flatulence, bloating and loose stools are very common and dose-limiting.
02 Mechanism
Competitively inhibits intestinal brush-border alpha-glucosidases (and pancreatic alpha-amylase), slowing conversion of complex carbohydrates and disaccharides to absorbable monosaccharides, thereby reducing post-prandial glucose and insulin.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Carb management (off-label) | 25–100 mg | Oral | Before high-carbohydrate meals |
| Diabetes | 25–100 mg | Oral | With the first bite of each main meal; up to 3x daily |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Blunted post-meal glucose/insulinSlows carbohydrate absorption, flattening glucose and insulin excursions. | Lower post-prandial spikes | Clinical | |
| Reduced fat storage from carb mealsLower insulin peaks may reduce fat deposition after large carbohydrate loads. | Observational |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Flatulence and GI distressMarked gas, bloating, abdominal cramps and loose stools. | Mild | Very common | Clinical | |
| Hypoglycaemia when combined with insulinLow blood glucose only when stacked with insulin or secretagogues. | Moderate | Uncommon | Clinical |