Table of Contents
How long does marijuana stay in blood

Detection Time in Blood
- Single use: Up to 24 hours
- Moderate use (few times/week): 1–3 days
- Chronic heavy use: Up to 7 days or more
THC Absorption and Elimination

- Peak blood levels: Within 3–10 minutes after smoking/vaping.
- Rapid drop: Within 30–60 minutes due to tissue absorption.
- Metabolites: Converted in liver to:
- 11-OH-THC (active)
- THC-COOH (inactive, detectable longer)
Detection Windows Based on Use
| Usage Type | THC Detection Time (Blood) |
|---|---|
| One-time use | Up to 24 hours |
| Occasional use | 1–3 days |
| Frequent use | 3–5 days |
| Daily/heavy use | 5–7+ days |
Factors Affecting Duration
- Dose and THC potency
- Frequency of use
- Body fat % (THC is fat-soluble)
- Metabolic rate
- Hydration status
- Route of administration (smoked vs. edibles)
Use of Blood Testing

- Preferred in DUI or workplace incidents
- Detects recent use and impairment
- Not suitable for long-term detection
Summary:
THC is detectable in blood for up to 7 days, depending on usage patterns. Blood tests are best for identifying recent consumption (within hours to a few days).