Here's how long various drugs stay in your system

One of the reasons that drug tests are a colossal scam is that not all drugs stay in your system for the same amount of time. In fact, some of the least dangerous drugs such as marijuana can be detected in your urine, blood, and hair for much longer than harder drugs such as heroin and meth — meaning that schools, employers, and law enforcement agencies that drug test disproportionately penalize marijuana users.

1. ALCOHOL

Urine: Three to five days
Blood: 10 to 12 hours
Hair: Up to 90 days

2. AMPHETAMINES

Adderall.

Urine: One to three days
Blood: About 12 hours
Hair: Up to 90 days

3. BARBITURATES

Urine: Two to four days
Blood: One to two days
Hair: Up to 90 days

4. CANNABIS

Urine: Seven to 30 days
Blood: About two weeks
Hair: Up to 90 days

5. COCAINE

Urine: Three to four days
Blood: One to two days
Hair: Up to 90 days

6. HEROIN

Urine: Three to four days
Blood: Up to 12 hours
Hair: Up to 90 days

7. LSD

LSD strips with "Dumbo" characters printed on them.

Urine: One to three days
Blood: Two to three hours
Hair: Up to three days

8. MDMA

Urine: Three to four days
Blood: One to two days
Hair: Up to 90 days

9. METHAMPHETAMINE

Urine: Three to six days
Blood: 24 to 36 hours
Hair: Up to 90 days

10. MORPHINE

Urine: Two to three days
Blood: Six to eight hours
Hair: Up to 90 days

With the exception of benzodiazepines (e.g. Valium), marijuana has the longest detectability. If you smoke a joint, it can be traced in your urine for seven to 30 days, depending upon your frequency of use and body type. That contrasts starkly with the detectability of more dangerous and addictive drugs, including heroin, meth, and cocaine.