Detection times

Detection times for cannabis (THC) – saliva, urine, blood, hair

Cannabis (THC) has the most variable detection window of all common drugs – anything from a couple of hours in saliva to over a month in urine for regular users. Here are the most common detection windows and what affects them.

Detection window

  • Saliva test

    Detection window
    1–24 hoursCaptures recent use; common in workplace testing

  • Urine – rapid test

    Detection window
    3–7 days (occasional), up to 30 days (regular)

  • Urine – lab-verified

    Detection window
    Up to 30 days with chronic use

  • Blood

    Detection window
    12–48 hoursBest for quantification

  • Hair

    Detection window
    Up to 90 days (3 cm hair segment)

Times are approximate and vary with dose, frequency, individual metabolism and cut-off value.

Factors that affect detection time

  • Frequency of use – chronic use gives a much longer detection time
  • Body fat – THC is stored in fatty tissue and released slowly
  • BMI and hydration – high values shorten detection somewhat
  • Amount and potency per occasion
  • Cut-off value in the analysis

Related

Frequently asked questions about cannabis (thc)

With occasional use, THC shows up in urine for 3–7 days. With regular use it can show up for up to 30 days, because THC is stored in fatty tissue and released slowly.

Dig deeper by substance

Substance-specific detection times

Detailed detection windows, contributing factors, and frequently asked questions per substance.

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Detection times for cannabis (THC) – saliva, urine, blood, hair