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How Long Does Meth Stay in Your System?

In 2018, an estimated 1.9 million (0.7%) Americans aged 12 or older used methamphetamine in the past year. (1)  If you’re worried about drug testing for employment, drug rehab testing, or for law enforcement charges, it makes sense to wonder how your body processes methamphetamines. Let’s look at how long meth stays in your system and how to handle law enforcement charges for meth possession.

How Long Does Meth Stay In Your System?

Methamphetamine is a highly addictive synthetic central nervous system stimulant classified as a Schedule II substance in the US and North Carolina. Recreational use is illegal, although there are legal pharmaceutical versions.

According to American Addiction Centers, “Unlike cocaine, a stimulant that’s quickly removed from and almost completely metabolized in the body, meth remains in the body—essentially unchanged by the body’s metabolism—much longer, leading to prolonged stimulant effects. 

The effects of meth can last anywhere from around 8-24 hours, depending on the amount taken, the time of day, how administered (IV, oral, etc.), how well the kidneys and liver are functioning, and the individual’s body chemistry.”

Employment Drug Testing

Methamphetamine metabolizes in the body to amphetamine. However, both drugs can test positive in your urine after methamphetamine use. Because your body breaks methamphetamine down into amphetamine, the drug test shows amphetamine only after time passes. (1)

According to Mayo Clinic Laboratories, a chemical amphetamine urine test can find amphetamine up to 3 days after use. If you use meth on a Friday morning, you’ll possibly not test positive for amphetamines on Monday afternoon. However, every person’s metabolism works differently. Proving methamphetamine use usually involves a positive methamphetamine result AND a certain amount of amphetamine positive result. 

False Positives

Watch out for other drugs or legal prescription medications that break down into amphetamines in your urine. You can test positive for amphetamine use with these drugs:

  • Selegiline
  • Famprofazone
  • Benzphetamine
  • Clobenzorex 
  • Amantadine
  • Benzphetamine
  • Bupropion
  • Chlorpromazine
  • Clobenzorex
  • l-Deprenyl
  • Desipramine
  • Dextroamphetamine
  • Ephedrine
  • Fenproporex 
  • Isometheptene
  • Isoxsuprine
  • Labetalol
  • MDMA
  • Methamphetamine
  • l-Methamphetamine (Vicks inhaler) 
  • Methylphenidate
  • Phentermine
  • Phenylephrine
  • Phenylpropanolamine
  • Promethazine
  • Pseudoephedrine
  • Ranitidine
  • Ritodrine
  • Selegiline
  • Thioridazine
  • Trazodone
  • Trimethobenzamide
  • Trimipramine (1)

“Because many providers have limited knowledge of immunoassay cross-reactivity data, patients with false-positive results may lose eligibility in rehabilitation programs, be inappropriately terminated from employment or suffer from medical staff bias because of lack of trust.” (2)

DWI and Meth

The question of how long meth stays in your blood or urine is also pertinent to criminal DWI charges. If a law enforcement officer pulls you over for impaired driving, they may ask you to come back to the police station for a blood test. 

The arresting officer must advise you of your right to refuse testing. However, if you refuse testing, you will face immediate revocation of your driver’s license for one year. You also have the right to contact an attorney or witness to observe the testing procedures within the 30-minute window after you’re charged.

Blood testing for methamphetamines finds any: Amphetamine, MDMA, MDA, MDEA. Some tests also include results for phentermine, ephedrine, pseudoephedrine, phenylpropanolamine, phendimetrazine, and diethylpropion.

If blood test results show a controlled substance in your blood, you may face DWI charges and conviction whether you were taking a legally prescribed medication as directed or not. You can face impaired driving charges if law enforcement believes you were impaired on a controlled substance, even before they get your blood test results back. The prosecutor can use the blood test results against you in court.

Methamphetamine Penalties

If you make your own shake and bake meth, you may also worry that drug testing will lead law enforcement back to your chemical lab, and charges could escalate against you. In North Carolina, drug crimes are no joke, and some of the penalties associated with charges include decades of prison time.

According to NC law, these are the felony charges you can face with methamphetamine use:

  • Class I Felony: if you possess a small amount of methamphetamine, you can face a max prison sentence of 24 months
  • Class H Felony: Packaging or repackaging methamphetamine, or labeling or relabeling the methamphetamine container with a maximum prison time of 39 months.
  • Class F Felony: Possessing between 28 to 199 grams can bring a penalty of 70 to 84 months in prison and a $50,000 fine.
  • Class E Felony: Possessing 200 to 399 grams carries a penalty of 90 to 117 months in prison and a $100,000 fine. 
  • Class C Felony: Manufacturing or possessing over 400 grams brings 225 to 279 months in prison and a $250,000 fine.

We Can Help

Whether you’re a first-time offender or someone who has been in the court system before with charges, we can help. Our experience working with prosecutors on drug crime charges helps us find the best-case scenario for your situation. 

Often first-time offenders can get reduced or deferred charges with successful completion in a treatment program for substance abuse. Our work in the court system protects your rights as we investigate all angles of law enforcement behavior and drug testing protocols. Contact us today and find out how we can help you.


  1. Urine Drug Screening: Practical Guide for Clinicians 
  2. False-Positive Interferences of Common Urine Drug Screen Immunoassays: A Review