Alcohol Metabolism: How Long Does It Take to Clear Your System?

The liver metabolizes alcohol at a relatively constant rate via alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). On average:

General Rule

• One standard drink (14 g pure alcohol ≈ 12 oz beer, 5 oz wine, 1.5 oz spirits) is cleared in ~1 hour for a healthy adult.
• Blood alcohol concentration (BAC) drops ~0.015% per hour (range 0.01–0.02%).

Factors Influencing Rate

Factor	Effect
Sex	Women have lower ADH activity and higher body fat % → slower metabolism, higher BAC per drink.
Body weight/composition	Higher weight and muscle mass → larger volume of distribution → lower peak BAC.
Age	Older adults: reduced liver volume, blood flow, and enzyme activity → slower clearance.
Food intake	Food (especially protein/fat) slows gastric emptying → slower absorption, lower peak BAC.
Medications	Some inhibit (e.g., H2 blockers) or induce ADH/CYP2E1; disulfiram blocks ALDH.
Genetics	ALDH2*2 variant (common in East Asians) causes acetaldehyde buildup → flushing, toxicity.
Liver disease	Cirrhosis significantly impairs metabolism.

Detection Windows

• Breath/blood: up to 12–24 hours after last drink.
• Urine (EtG/EtS): 24–80 hours.
• Hair: up to 90 days.

Important: No method (coffee, cold shower, exercise) accelerates metabolism. Only time lowers BAC.