Substance guides

How long does Valium stay in your system?

Published June 12, 2025 · 7 min read · Updated April 2026

Reviewed for accuracy by licensed clinical professionals.

Valium (diazepam) is a long-acting benzodiazepine with a half-life of 20-100 hours. Its active metabolite nordiazepam has an even longer half-life of 40-200 hours, making Valium detectable far longer than short-acting benzos.

Detection by test type

Urine: up to 6 weeks after chronic use, making Valium one of the longest-detectable benzodiazepines. Occasional use may be detectable for 1-2 weeks. Blood: 2-7 days. Hair: up to 90 days.

Why so long

The extremely long half-lives of both diazepam and nordiazepam mean the drug accumulates with repeated dosing and takes weeks to fully clear. Body fat acts as a reservoir.

Clinical use in detox

Ironically, Valium's long half-life makes it the preferred benzodiazepine for detox cross-tapering, providing smooth, stable blood levels during benzo and alcohol withdrawal.

Authoritative sources

This article references guidelines from: SAMHSA · NIDA · ASAM

Frequently asked questions

How long does Valium stay in urine?

Up to 6 weeks for chronic users, 1-2 weeks for occasional use. Valium is one of the longest-detectable benzodiazepines.

Why does Valium last so long?

Diazepam and its metabolite nordiazepam have very long half-lives (20-200 hours combined), causing accumulation with repeated use.

Is Valium more addictive than Xanax?

Both are addictive. Xanax produces faster onset and more intense effects. Valium has a smoother, longer profile. Both require medical tapering for discontinuation.

Disclaimer: Informational only. Not medical advice. SAMHSA: 1-800-662-4357.