Detectability of drugs – How long substances remain recognizable in the body

Drugs can be detected in the body for different lengths of time depending on the substance, amount of consumption and test method. This section provides you with a clear, neutral, and scientifically sound overview of how long common substances can be detected in urine, saliva, blood, or hair – and why detection times can vary greatly from person to person.

Why do detection times differ so much?

Detectability does not only depend on the drug itself. Several individual factors influence how quickly the body breaks down substances:

  • Frequency of consumption (one-off, occasional, regular)
  • Metabolism & Body Fat Percentage
  • Hydration
  • Body weight
  • Type of test method
  • Sensitivity / cut-off value of the test
  • Age and health status

Especially with THC, the differences can be enormous – from a few days to several weeks.

Detectability depending on the test method

Urine tests

Urine is the most common test method. Suitable for home use, workplace and quick checks.

  • Good sensitivity
  • Easy to use
  • Detectability: medium to long, depending on the substance

Most substances remain in the urine for 1–4 days, but THC much longer.

→ Ideal for screening tests

Saliva tests

Saliva tests mainly indicate more recent or recent consumption. The detection times are significantly shorter than in urine.

  • Simple & hygienic
  • Quick result
  • Detection from a few hours to 1–2 days

→ Ideal for road traffic or quick checks

Hair analyses

Hair analyses can indicate substance use over weeks to months.

  • Very long traceability (depending on hair length)
  • is used for forensic purposes
  • suitable for long-term review

→ Not suitable for short-term checks

Blood tests

Blood shows only very short-term consumption:

  • few hours to 1 day
  • Precise, but invasive
  • is mainly used in road traffic or emergency medicine


Typical detection times at a glance

(These values are approximate values. Individual differences are possible.)

Substance Urine Saliva Blood Hair
Cannabis (THC) 3–30 days 4–24 h 2–12 h up to 90 days
Cocaine 2–4 days 5–24 h 1–12 h up to 90 days
Amphetamines/Speed 1–4 days 12–48 h 6–24 h up to 90 days
MDMA (ecstasy) 1–3 days 12–48 h 6–24 h up to 90 days
Opiates 1–4 days 12–36 h 6–24 h to up to 90 days
Benzodiazepines 3–30 days 6–48 h 6–48 h up to 90 days
New psychoactive substances vary strongly vary strongly variable variable

For exact values, the respective test is always decisive (cut-off value).

What does the cut-off value mean?

The cut-off value is the detection limit above which a test evaluates a result as positive.
It prevents extremely small, irrelevant residues from leading to a „positive“.

The lower the cut-off value:

  • the more sensitive the test
  • the longer the detectability

Each substance and each test has its own limit values.

Why THC in particular has been detectable for so long

THC is fat-soluble. This means:

  • it is stored in fat cells
  • is slowly released again
  • the body breaks it down much more slowly

Therefore, the detection can take several weeks with regular consumption.

What happens if the result is positive?

A positive screening initially only means:
A substance has been detected – but not how much or when exactly.

In the case of important issues (employers, authorities, traffic), a confirmatory analysis is usually carried out in the laboratory:

  • by means of LC-MS/MS
  • very precise
  • Clearly detectable, no cross-reactions

Further topics:


The detectability of drugs is complex and depends on many factors. However, with the right testing method, you will get reliable results. This area provides you with all the important information so that you can correctly interpret the different detection times and select suitable test procedures.