When does meth kick in?

The time it takes for meth to kick in varies by HOW you take it. However, once methamphetamine is absorbed, the biological effects are the same regardless of the route of exposure. More on meth onset here.

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There are a number of factors which affect the onset of meth and its effects on the body. One important factor which influences drug onset is mode of administration. Methamphetamine hydrochloride can be inhaled (smoked), snorted, injected, or ingested, with injection and inhalation producing the most rapid onset and ingestion resulting in delayed onset.

In general, once methamphetamine is absorbed, the biological effects are the same regardless of the route of exposure. Peak blood methamphetamine concentrations occur shortly after injection, a few minutes after smoking, and around 3 hours after oral dosing. More here on how d-methamphetamine works, with a section for your questions about why people use meth or problems with meth at the end.

Meth active ingredients

The main ingredient in meth is methamphetamine hydrochloride. This chemical is present as wither a yellow or white crystalline powder or as “ice,” a large, usually clear crystal of high purity. What are the components of these forms of meth?

Free base (“methamphetamine base”), is the initial product of meth and is a liquid at room temperature. The hydrochloride salt is produced from the free base by bubbling hydrogen chloride gas through it. However, methamphetamine also contains one optically active carbon atom. Consequently, there are two isomeric forms of methamphetamine, called d-methamphetamine and l-methamphetamine. The d-isomer is more potent than the l- isomer; most all of the methamphetamine produced by illegal labs is the d-isomer. d-methamphetamine is a controlled substance in the United States and is only available by prescription for legitimate medical uses in the treatment of ADHD or short term treatment of obesity.

Factors that influence meth onset

For a drug to work, it must enter the body, dissolve into a solution, be absorbed by the body and the distributed to sites of action. And in the process, a number of different factors can affect the rate at which drug onset begins. These include:

  1. Drug bioavailability – Intranasal and smoked methamphetamine are well absorbed. Although intranasal or smoked routes may decrease the risk of transmission of blood-borne diseases, exposure to methamphetamine and the possibility of drug-related complications remain substantial.
  2. Drug form – Meth comes in several forms, including powder, crystal, rocks, and tablets. When it comes in the crystal form it is called “crystal meth.” The type of meth you take will influence onset of effects.
  3. Mode of administrationHow meth is abused affects onset of effects. Routes of methamphetamine administration are varied, with prior reports of exposure via nasal insufflation, IV administration, ingestion of liquid formulations, and a single case report of intravaginal exposure. Each of these effect onset of effect. Also, the producers of meth change the way that drugs dissolve in order to modify solubility characteristics, and therefore slow or quicken drug onset. Here is a general list of fastest to slowest drug delivery forms:


  • Liquids, elixirs, syrups
  • Suspension solutions
  • Powders
  • Capsules
  • Tablets
  • Coated tablets
  • Enteric-coated tablets 


When does meth start working?

Methamphetamine is readily absorbed from the GI tract and absorption is usually complete by 4-6 hours.  How long can meth last? Effects persist for 6 to 12 hours and may persist up to 24 hours after large doses. Peak plasma levels of meth occur within 1 to 3 hours, varying with the degree of physical activity and the amount of food in the stomach.

When does meth peak?

Peak blood methamphetamine concentrations occur shortly after injection, a few minutes after smoking, and around 3 hours after oral dosing. Following oral administration, peak methamphetamine concentrations are seen in 2.6-3.6 hours and the mean elimination half-life is 10.1 hours (range 6.4-15 hours). Following intravenous injection, the mean elimination half-life is slightly longer (12.2 hours).

When does meth wear off?

The effects of methamphetamine on humans are profound. The stimulant effects from methamphetamine can last for hours. Often the methamphetamine user remains awake for days. As the high begins to wear off, the methamphetamine user enters a stage called “tweaking,” in which he or she is prone to violence, delusions, and paranoia.

Risks of meth addiction

Meth use can quickly lead to addiction. For one thing, its long half life and duration of effects are attractive for their euphoric effect. However, you can quickly become physically dependent on meth and it causes tolerance. People who abuse meth start needing to take more of it to get the same initial high. People who usually eat or snort meth might start to smoke or inject it to get a stronger, quicker high. Additionally, the psychological need for meth can compel continued use, especially when underlying psych-emotional issues go unresolved.

People trying to quit taking meth can experience any of these common effects:

  • Be unable to feel happy
  • Feel a very strong need to take meth
  • Feel angry or nervous
  • Get really tired but have trouble sleeping

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When does meth kick in questions

We hope to have answered questions about the onset of meth’s effects in this article. But if you still have questions about meth effects and risk of using it, please write them in the section below. We will do our best to answer them promptly.

Reference Sources: OEHHA: Methamphetamine
TOXNET: d-methamphtamine
PublicSafety: Methamphetamine – How It’s Made
NIDA: DrugFacts – Methamphetamine
NIDA for teens: Methamphetamine (Meth)
NHTSA: Methamphetamine (and Amphetamine)
NCJRS: Methamphetamine: A Dangerous Drug, A Spreading Threat
Justice: Meth Awareness
NCJRS: The National Methamphetamine Drug Conference
NCBI: Bottoms Up: Methamphetamine Toxicity from an Unusual Route
About the author
Lee Weber is a published author, medical writer, and woman in long-term recovery from addiction. Her latest book, The Definitive Guide to Addiction Interventions is set to reach university bookstores in early 2019.
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