Diazepam (often known by the brand name Valium) is a fast-acting benzodiazepine typically used for anxiety or muscle spasms. When taken orally in tablet form, it usually begins to take effect within 30 to 60 minutes, reaching peak levels in the bloodstream around the 90-minute mark. For travelers with a fear of flying, it is often recommended to take the dose about an hour before boarding. If administered intravenously (IV) in a clinical setting, it works almost instantaneously, usually within 1 to 5 minutes. The duration of its effects can be quite long; diazepam has a "long half-life," meaning it stays in your system much longer than other anti-anxiety meds like Xanax. In 2026, it is strictly a prescription-only medication globally, and users are cautioned that it can cause significant drowsiness, impaired coordination, and "rebound anxiety" if used frequently. Because it can be habit-forming, it is generally intended for short-term use under strict medical supervision.