How Amphetamine Works: The Short Answer

Amphetamine works by boosting levels of two brain chemicals — dopamine and norepinephrine — that play key roles in attention, focus, and motivation. In people with ADHD, these chemicals are often underactive. Amphetamine helps restore them to more typical levels, which is why it improves concentration and reduces impulsive behavior.

What Amphetamine Does in Your Brain

To understand how Amphetamine works, it helps to know a little about how your brain communicates. Your brain cells (neurons) send messages to each other using chemicals called neurotransmitters. Two of the most important ones for attention and focus are:

• Dopamine — involved in motivation, reward, and pleasure
• Norepinephrine — involved in alertness, attention, and the "fight or flight" response

In people with ADHD, these neurotransmitters don't work quite right. Think of it like a mail system: your brain is sending messages, but they keep getting lost or returned to sender before they reach their destination.

How Amphetamine Fixes the Problem

Amphetamine does two main things:

1. It increases the release of dopamine and norepinephrine. Think of this as your brain suddenly sending out more mail. Amphetamine tells your neurons to push more of these chemicals out into the gap between brain cells (called the synaptic cleft).
2. It blocks reuptake. Normally, after a neurotransmitter delivers its message, it gets pulled back into the sending neuron — like a message being recalled. Amphetamine slows this process down, so dopamine and norepinephrine stay active longer.

The result? More dopamine and norepinephrine are available for your brain to use, which improves focus, attention, and impulse control.

Amphetamine also has a minor effect on monoamine oxidase (MAO), an enzyme that breaks down neurotransmitters. By slightly inhibiting MAO, Amphetamine helps these brain chemicals stick around even longer.

How Long Does It Take to Work?

How quickly Amphetamine kicks in depends on the formulation:

• Immediate-release (IR) — such as generic Adderall IR — typically starts working within 30 to 60 minutes after you take it.
• Extended-release (XR) — such as Adderall XR or Mydayis — may take 1 to 2 hours to reach full effect because the medication is released gradually.

Most people notice improved focus and reduced distractibility relatively quickly. However, your doctor may need several weeks to find the right dose for you.

How Long Does It Last?

The duration of Amphetamine's effects also varies by formulation:

• Immediate-release (IR): About 4 to 6 hours per dose. Most people take it 2 to 3 times per day.
• Extended-release (XR): About 10 to 12 hours with a single morning dose.
• Mydayis: Designed to last up to 16 hours thanks to its triple-bead technology.

This is why your doctor will choose a formulation based on how long you need coverage during the day. If you need focus for school or a standard workday, XR may be enough. If you need coverage into the evening, Mydayis might be a better fit.

What Makes Amphetamine Different From Similar Medications?

Amphetamine isn't the only stimulant used for ADHD. Here's how it compares to the most common alternatives:

Amphetamine vs. Methylphenidate (Ritalin, Concerta)

Both are CNS stimulants, but they work slightly differently. Methylphenidate primarily blocks reuptake of dopamine and norepinephrine. Amphetamine goes a step further by also increasing the release of these chemicals. Some people respond better to one than the other, which is why doctors sometimes switch between them.

Amphetamine vs. Lisdexamfetamine (Vyvanse)

Lisdexamfetamine is actually a prodrug of Amphetamine. That means your body has to convert it into active Amphetamine before it works. This gives Vyvanse a smoother onset and is thought to have a lower potential for abuse. However, the active drug in your system is essentially the same.

Amphetamine vs. Non-Stimulants (Strattera, Qelbree)

Non-stimulant medications like Atomoxetine (Strattera) and Viloxazine (Qelbree) work differently — they primarily block norepinephrine reuptake without significantly affecting dopamine release. They take longer to start working (often weeks), but they don't carry the same abuse potential as Amphetamine. They're often used when stimulants cause too many side effects or aren't appropriate. Learn more in our guide on alternatives to Amphetamine.

Final Thoughts

Amphetamine works by increasing the availability of dopamine and norepinephrine in your brain — two chemicals essential for focus, attention, and motivation. It starts working within 30 minutes to 2 hours depending on the formulation, and its effects can last anywhere from 4 to 16 hours.

Understanding how your medication works can help you use it more effectively and have better conversations with your doctor about dose adjustments and formulation changes.

For more information, read our guide on what Amphetamine is, learn about potential side effects, or use Medfinder to find a pharmacy with Amphetamine in stock near you.