Methamphetamine vs Amphetamine: What is the Difference?

Understanding the distinction between methamphetamine and amphetamine is crucial for anyone seeking clarity on these substances, which, while chemically related, have significantly different impacts on the individual’s health and well-being. Both fall under the category of stimulants, a group of drugs known for their ability to increase alertness, attention, and energy. However, their differences lie in their potency, legality, and potential for abuse and addiction.

Methamphetamine, often referred to simply as meth, is a highly addictive illegal drug that has a profound stimulating effect on the central nervous system. It is known for its rapid onset of euphoria but carries with it a high risk of leading to severe physical and psychological issues, including cardiovascular disease.

Amphetamines are a class of drugs that include both prescription medications used to treat conditions like ADHD and certain illegal drugs. While some amphetamines can be obtained through a prescription and, when used correctly under medical supervision, are considered safe, they can still be misused. The misuse of prescription amphetamines or the use of amphetamine as an over-the-counter medication in some countries raises concerns about their potential for addiction.

At Castle Craig, we understand the complexities of addiction, especially when it comes to stimulants like methamphetamine and amphetamine. Our team of experts is dedicated to providing compassionate care and comprehensive treatment to those struggling with the misuse of these substances.

If you or someone you know has been misusing methamphetamine, amphetamine, or any other illegal drugs and suspect addiction, we encourage you to reach out. Recovery is possible, and Castle Craig is here to support you every step of the way.

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What is Amphetamine?

Amphetamine is a term that refers to a group of stimulants that similarly impact the brain. Drugs in this class include amphetamine, dexamphetamine, methylphenidate and ephedrine.

  1. Amphetamine is a combination of identical-looking forms in equal quantities, consisting of a ‘d’ form also called dexamphetamine and an ‘’l’ form. Amphetamine was first manufactured as a medication in 1935 as Benzedrine to treat narcolepsy and depression,
  2. Dexamphetamine is the more potent of the two forms of amphetamine and was found to improve concentration in children with Attention Deficit Hyperactivity Disorder (ADHD). Dexamphetamine was first manufactured as Dexedrine. and later as Adderall, as a mixture of d and l forms of amphetamine in a 3:1 ratio. Lisdexamphetamine is a form of dexamphetamine that is converted into dexamphetamine in the gut and is licensed for the treatment of ADHD.   
  3. Methylphenidate was first used in the 1950s for the treatment of narcolepsy and then for ADHD. It is manufactured under the brand name, Ritalin.
  4. Ephedrine is a naturally occurring drug found in plants and used in cold and cough remedies, where it is used as a decongestant.

Common street names for amphetamine and dexamphetamine include Addys, Uppers, Beans, Black Beauties, Pep Pills, Speed, Dexies, Zing, Study Buddies, and Smart Pills. Street names for methamphetamine include Crystal, Meth, Cristy, Tina, Crank, Crissy, Tweak, Glass, Ice, Shards, Go, Whizz and Chalk.

What is Methamphetamine?

Methamphetamine was first discovered in the 1890s and later used as a treatment for narcolepsy, and asthma and to reduce weight as an appetite suppressant. It was later developed into a more potent crystal form in 1919.

Both amphetamines and methamphetamine were given to the Allied Forces during World War 2 to increase energy, improve alertness and reduce the need for sleep. There was little awareness at that time of their potential for addiction.

How Do Stimulants Work?

Stimulant drugs, also known as stimulants, work by increasing the activity of the central nervous system (CNS), which consists of the brain and spinal cord. They enhance certain bodily functions and processes, resulting in increased alertness, attention, and energy. The mechanisms through which stimulants achieve their effects involve several neurotransmitters, which are chemicals that transmit signals in the brain. The most significant neurotransmitters affected by stimulants are dopamine, norepinephrine, and to a lesser extent, serotonin

Differences Between Using Amphetamine and Methamphetamine

Amphetamine and methamphetamine cause the release of the chemicals dopamine and noradrenaline from the brain, as well as the release of adrenaline from the body. Dopamine release is responsible for the pleasurable effects, with noradrenaline and adrenaline responsible for over-stimulation of the brain and the body’s “fight or flight” reaction more commonly experienced in extreme fear to prepare the body for escape and confrontation.

Amphetamine is made as tablets, capsules or as an oral solution which can be ingested or as a powder which can be snorted or dissolved in water for injection. The common form of amphetamine addiction is the powder form, also known as “speed”.

Methamphetamine is also made as a powder which is snorted or injected. In its most potent form, it is manufactured as ‘crystal meth’, which is commonly smoked but also injected.  Smoking or injecting methamphetamine causes an immediate “rush” or “flash” that lasts only for a few minutes, with an immediate feeling of euphoria described as more pleasurable than amphetamine, dexamphetamine or snorted methamphetamine.

For snorted amphetamine and methamphetamine use, the effects peak at around 30 minutes. When ingested, the effects peak at around 3 hours. The immediate effects of amphetamine and methamphetamine last around 12 hours.

Because it is more potent than its amphetamine, dexamphetamine has a higher likelihood of addiction. More potent still is Methamphetamine, with longer-lasting effects at comparable doses and an even higher risk of addiction. This is because of the rapid “crash” after use, with more frequent use to obtain the same rush.

As such, methamphetamine is classified as a Class A Drug that is illegal in all forms. Amphetamine is a Class B drug, which means that in certain forms, it can only be prescribed by doctors with expert knowledge of addiction. Although powder methamphetamine is prescribed in the United States as Desoxyn, it is classified as a non-prescribed Class B drug in the UK. Crystal Meth is a Class A drug.

Harmful effects of amphetamine and methamphetamine

Both amphetamine and methamphetamine have similar effects during intoxication, withdrawal and addiction.


  • Physical symptoms The effects of adrenaline and noradrenaline released by the drugs cause a rapid heartbeat, high blood pressure, rapid breathing, facial flushing, headache, nausea, vomiting, and abdominal pain 
  • Memory problems Short-term memory loss, with better recall of positive experiences from drug abuse
  • Abnormal beliefs and experiences                                                                                                     Delusions of persecution that there is a danger to life from being harmed, spied on or followed. Auditory hallucinations are often threatening and abusive. Collectively delusions and hallucinations are known as psychotic symptoms, which may be indistinguishable from the symptoms of schizophrenia
  • Anxiety Overstimulation of the brain can result in severe anxiety with the development of panic attacks and other mental health issues such as depression
  • Insomnia  Increased alertness means that sleep is suppressed with a delay or inability to sleep, which can last for days. This is known as ‘tweaking’, which can lead to a worsening of psychotic symptoms and fatigue
  • Aggression Lack of control over behaviour can lead to verbal and physical aggression
  • Self-harm Increased risk of self-harm from impulsivity
  • Stereotyped behaviour Repetitive, purposeless movements such as hand shaking or waving, head banging, putting objects in the mouth, nail-biting and rocking


Low mood, loss of interest, fatigue, agitation, irritability, and poor concentration are common. The inability to get to sleep or sleep more may also occur, as it may increase appetite and strong cravings. It can take weeks for amphetamines and methamphetamine to leave the body and several months for the body to readjust to a healthy state.

At Castle Craig, we provide specialist assessment and medically-managed detoxification to reduce discomfort from withdrawal symptoms experienced in amphetamine addiction, followed by abstinence-based recovery with a focus on individualised treatment and a 12 Step treatment model.

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There is a high risk of addiction to amphetamine, particularly with heavy and prolonged use. The more immediate the immediate effect, such as in smoked crystal meth, the more frequent the use. Escalating amounts are often used because of the brain’s ability to adapt to the effects of the drug. This is called tolerance and results in more of the drug taken to achieve the same effect or a less pleasurable effect from the same drug dose.

  1. Light use is 6 mg – 15 mg per day, with 15 mg – 30 mg per day the most common pattern.
  2. Strong use is 30 mg – 50 mg per day and very strong use 50 – 150 mg per day.

In addition to tolerance, withdrawal symptoms, difficulty controlling the amount of drug used and difficulty cutting down use, other symptoms define amphetamine addiction which include

  • Continued to use the drug despite the negative impact on health, relationships and everyday activities
  • Important activities are given up or reduced
  • Continuing to use the drug in situations in which it poses a risk, such as driving

Living with addiction can be devastating but help is at hand. At Castle Craig, we provide a free, confidential assessment from medical experts who can help you examine signs of addiction and suggest ways that we can help to best manage your addiction.

  • What are the long-term physical health risks from amphetamine and methamphetamine?

    Long-term use can result in serious physical consequences such as brain damage, seizures, stroke and overheating of the body.

  • Are there particular risks from methamphetamine?

    Methamphetamine misuse carries more serious risks seen more often than with amphetamines, including the following:

    • Adulteration can change the potency and purity, with the addition of other drugs such as caffeine and amphetamines such as ephedrine
    • Use in chemsex can increase the risk of sexually transmitted diseases
    • Impulsivity and aggression can be severe, with the risk of violence
    • Psychotic symptoms can last longer
    • Damage to arteries in the heart can cause inflammation, and blockage, leading to heart attack, heart failure and stroke
    • Damage to the oral cavity is called “Meth Mouth”, with the development of gum disease and tooth decay. This can be worsened by teeth grinding during drug use, called bruxism
    • Skin irritation can occur from “Meth Mites”, with constant picking from the feeling of bugs crawling on the skin, This can result in open wounds and the risk of infection
    • Increased susceptibility to infection can occur from suppression of the immune system
    • Kidney damage can occur from damage to blood vessels
    • Muscle damage results from inflammation
    • Liver disease from hepatitis can lead to cirrhosis

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Getting help for amphetamine and methamphetamine addiction

Addiction to all forms of amphetamine, including dexamphetamine, as well as methamphetamine requires expert assessment and treatment. 

A thorough medical assessment involves assessing your level of drug use so that we can tailor detox to your needs to minimise withdrawal symptoms. Our detox specialists can help you manage problems such as insomnia, depression, and impulsivity. Rehab in an environment in which you feel safe and secure to make the most of your journey to recovery involves a focused approach to personalised therapy and peer support. 

Given that it may take weeks for your body to re-adjust to amphetamine addiction, a typical rehab is between 28 and 30 days for assessment, diagnosis, detox, and therapy, with the opportunity to extend to 90 days if your needs are more complex.

We firmly believe that recovery is possible from both amphetamine and methamphetamine addiction. At Castle Craig, we will be there for you all the way.

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