Meth Metabolism in the Body: How Meth Affects the Brain (INFOGRAPHIC)

People take meth either via injection, ingestion, inhalation, or insertion into the anal cavity. After meth enters into the bloodstream, it is carried through the circulatory system to the brain. Meth’s damage has damaging effects which are physically manifested in user’s appearance. Learn about how meth works in the brain and body here, with a section at the end for your questions.

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How Meth Really Works

In this meth infographic, we’ll describe how meth works on the body. We graphically describe the metabolism involved when you take meth and how it gets to the brain. Find out more about how meth really works here.

At the end, we invite you to post your questions and feedback on the subject of meth effects on the brain and body. We value your experiences and make sure to provide you with a personal and prompt response.

Meth Metabolism in the Body: How Meth Affects the Brain (INFOGRAPHIC)

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Meth is Highly Effective, but Highly Addictive

Q: Why do people use meth?

A: Most people reach for meth (methamphetamine) because it changes the way they feel.

Some people take meth to dampen painful emotion. Others use meth because it’s really effective at getting you high for up to 10-12 hours. In fact, the meth high can last for a very long time. But at the root, using meth can really be a defense mechanism against pain. In some cases, regular use has even been clinically considered “self-medication”.

Meth works in the brain to trigger a chemical euphoria.  But this high comes at a cost. The psychoactive effects of methamphetamine are dual in nature. On the one side, methamphetamine produces euphoria – a sense of extreme well-being. But on the other side, this drug can damage both your brain and your body.


Methamphetamine in the Brain

Methamphetamine works by increasing the amount of the natural feel good chemical, “dopamine”. This hormone is involved in body movement, motivation, pleasure, and reward stimulated by natural behaviors. Meth’s ability to release high levels of dopamine rapidly in reward areas of the brain produces the “rush” (euphoria), or “flash” that many people experience. But the high isn’t the only effect of meth.

The effects felt after long-term meth use include:

  • aggressive or violent behavior
  • changes in brain structure and function
  • deficits in thinking and motor skills
  • increased distractibility
  • memory loss
  • mood disturbances
  • severe dental problems
  • weight loss

Trying to live with meth in your system constantly is like tasking the body to work ten times faster than normal. The end result?  The stimulation becomes too much; your brain and body get burned out.


How Does Meth Work In The Body?

1. YOU TAKE METH: It can be administered orally, smoked, injected, or snorted.

2. STOMACH: Eating meth produces effects in about 20-45 minutes because it has to travel through the digestive system. Some of it gets absorbed into the bloodstream along the way and some gets filtered out through the liver and kidneys.

3. LUNGS: Methamphetamine is well absorbed into the bloodstream after smoking or intranasal administration, with bioavailabilities of 79% after snorting and 37.4% after smoking.

4. HEART: Following administration, methamphetamine reaches the bloodstream fairl intact. As the heart pumps blood throughout the body it carries the drug with it.

5. BRAIN: Meth quickly passes the blood-brain barrier. In the brain, it increases the levels dopamine, serotonin (5-HT) and norepinephrine. It speeds up the work of the whole body and produces locomotor effects, psychosis, and perception disturbances.

6. LIVER: Methamphetamine is broken down in the liver. It is mainly metabolized to amphetamine.

7. KIDNEYS: Between 30-54% of an oral dose is excreted in urine as unchanged meth and 10-23% as unchanged amphetamine. Following an intravenous dose, 45% is excreted as unchanged meth and 7% amphetamine. The half-life of meth can be anywhere in the range of 5 – 30 hours.


  • Quarter = 0.25 gr or 0.01 oz
  • Half = 0.50 gr or 0.02 oz
  • Teenager = 1.8 gr or 0.0625 oz
  • 8-Ball = 3.5 gr or 0.125 oz

Meth In The Body Questions

We strive to educate and inform all our readers about the damaging consequences of meth use. One of the ways we provide our help is by answering the questions you ask. Now, we welcome you to post your questions and comments in the designated section below. We’ll do our best to provide a personal and prompt response to all legitimate inquiries.

Reference Sources: NHTSA: Methamphetamine (And Amphetamine)
NCBI: The bioavailability of intranasal and smoked methamphetamine
NCBI: Effects of repeated oral methamphetamine administration in humans
DrugAbuse: How is methamphetamine abused?
NIH: What are the long-term effects of methamphetamine abuse?
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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  1. I’ve done meth countless times, not that I’m proud to say but I actually just took a shot not even 10 minutes ago. It feels amazing, the very beginning or “the rush” is what I seem to not be able to get enough of. I couldn’t describe it negatively even though I know its terrible for me to be continuing on my path of drug use.

    I started as a heroin user, actually oxycontin but became a heroin addict once they quit making the pills crushable. I snorted them but immediately started banging heroin as my so called boyfriend introduced me to my poison. I’ve been battling my addiction for 9 long years and have over dosed on heroin at least 5 times. I’ve been in jail sent to the “big house”, lost loved ones relationships because of my drug use and even died & still I cant help but run back to it? I know. I feel that if most of you went thru the things I went thru in life that you wouldn’t be judging me right now, so enough of that. I’m sharing to vent and maybe ..

    Help someone who knows? I’m a mother to two beautiful boys and yes , I ha e custody of both thank you very much! Maybe I shouldn’t? Fuck that. I don’t get high around my kids and would NEVER put them in harm’s way! I’m with the father of my kids and he is sober, straight laced and has a good job. I guess you could say I’m lucky to of landed such a great man& for him to want to stay a family with me even though I’ll always be an addict using or not…just a recovering addict. I say JUST, but a recovering addict is EVERYTHING to me and for some reason I keep destroying my months of sober time to go and get high again…even if life is going good? I just don’t get it. Addiction is one of the hardest things I e gone thru in life and I e already lost both parents Dad 11 years ago& Mom a little over a year ago) I have pent up anger that it had to happen to MY family… my dad killing himself with no warning or goodbye& Mom turning to the bottle because she lost the love of her life, her HS sweetheart. I seriously old have the world by the balls but for some reason I feel I don’t deserve anything good and self sabotage whatever might be positive in my life.

    I have all I’ve ever wanted now, a loving family but I’m still incomplete? Why am I not happy with my soul mate and two perfect toddlers? I think some grief that I’ve refused to heal from, let go or think of is the underlying problem and answer to the start of my road to recovery. I often wonder if I should just overdose one of these times? I’d I cant get sober and stay so er…I’m going to hurt my family the way that I was so badly hurt growing up& that’s the last thing I’d want to do to my man& children.

    I’m sick of it. How can I help heal my hurt of losing my parents and anger that my father chose to leave me? I also feel that if I could overcome losing my parents, I would be able to o welcome anything besides losing anymore family …..than I’ll need the nutward ZTAT, not even joking or it’s going to be my funeral next intentionally or not by a drug over dose.

  2. i am basically dual addicted.I am addicted to meth and pornography. I don’t do one without the other. I don’t watch porno unless I have meth.Once I put in I can nothing else. this goes on for 2- 4 days.
    I have been doing this combination for over twenty years. The longest I’ve
    been clean is a little less than 11 months. After a binge I am full of self loathing and vow to stop. After about two weeks the thought will come in and I decide to use
    It never ceases to amaze and baffle me to go ahead and use knowing the great amount of suffering it causes.

    1. Hi Alan. If you have questions about addiction treatment and your options, immediate assistance is available. Call our free hotline to speak with a trusted treatment consultant.

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