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Drug Info

How long does it take Adderall to work?

Adderall begins working as quickly as 30 minutes after ingestion
Rebecca Rovenstine writer headshot
By | Jul. 8, 2024 Medically reviewed by Anne Jacobson, MD, MPH
An analog alarm clock and two Rx tablets: How long does it take Adderall to work?

Key takeaways

  • Adderall works to manage the symptoms of ADHD by helping individuals focus and concentrate.

  • Since Adderall is a stimulant, it also helps those with narcolepsy stay awake during the day.

  • The average adult dose of Adderall can be anywhere between 5 mg to 40 mg daily. It may be given in divided doses.

  • Adderall can take longer to work on a full stomach or when taken with certain medications or foods.

In this article:

Adderall, sold under the generic version of amphetamine/dextroamphetamine) is a stimulant medication approved by the U.S. Food and Drug Administration to treat the symptoms of attention deficit hyperactivity disorder (ADHD). Adderall is also used to help people with narcolepsy stay awake during the day.

There are two types of Adderall: Adderall IR and Adderall XR. Adderall IR, or immediate release (IR), starts to work quickly after taking the capsule, but the effect does not last as long. Adderall XR, or extended-release (XR), lasts longer throughout the day but takes longer to provide the full effects. Depending on which treatment option a person is taking, Adderall can begin working anywhere from 30 minutes to one hour after administration. 

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How long does Adderall take to work? 

Depending on which type of Adderall your psychiatrist or healthcare provider has prescribed, the length of time it takes for Adderall to begin working to alleviate ADHD symptoms is usually 30 minutes to one hour. However, at this early stage, the medication is not yet providing its full effects.

“Immediate-release Adderall can take up to three hours to fully kick in while the extended-release formulation can take up to seven hours,” states Kenneth S. Fill, Pharm.D., who works at Drugwatch.

People will know the medication is working when it begins to improve executive functioning skills, like focus and concentration, which are often difficult for those with ADHD. 

“Individuals taking Adderall at appropriate doses may experience an improved sense of focus, feel more alert, less fidgety, and a sense of calmness once it takes effect,” said psychiatrist Dr. Cooper Stone. He added that some people only note improvements after taking it for a longer period of time. “On a longer-term time frame, individuals may report feeling less stressed and less anxious as a result of no longer falling behind on tasks and responsibilities that may have previously piled up and led to distress,” he said.

However, Dr. Stone also noted that anxiety can be a common side effect of taking the stimulant Adderall.

The therapeutic effects of Adderall IR last about 4-6 hours. For Adderall XL, it’s more like 8 to 12 hours. But it can be detected in your body for much longer than that. The timeframe can increase for those on high doses or for people who have been taking the medication for a long time.

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What can affect how long it takes Adderall to work?

There are a few factors that can affect the length of time Adderall takes to begin working.

Food Interactions

Certain foods can affect the body’s potential to absorb Adderall. This includes: 

  • Vitamin C
  • Acidic foods
  • Acidic drinks
  • Fruit juices

“For example, if prescribed Adderall, one should avoid taking it with coffee,” said Dr. Stone. “Instead, one should wait 30 minutes to 1 hour before ingesting food for maximum effect.”

Medication Interactions

Like many prescription drugs and over-the-counter medications, some medications can interact with Adderall, making a difference in how it works.

Just as acids affect the absorption of Adderall, medicines that decrease stomach acid can strengthen its effects.

Dr. Stone explained, “Medications that reduce stomach acidity, such as the class of medications known as proton pump inhibitors (often used for acid reflux), may increase the absorption of Adderall.”

Other medications that may affect or interact with Adderall include:

There are other prescription and over-the-counter medications that may interact with Adderall. Because of this, Fill advises, “Be sure to discuss drug interactions with your doctor before starting Adderall.”

Taking Adderall Before and After Eating

“If an individual who consistently took Adderall on an empty stomach were to take Adderall with food, then they may notice the medication will be less effective due to reduced absorption and delayed onset,” explained Dr. Stone. “While it is okay to take Adderall with or without food, it’s important to choose one way and to be consistent with how one takes it.”

On the other hand, if someone begins taking the medication on an empty stomach, Adderall may kick in faster.

Developing a Tolerance

One thing that can make Adderall less effective is when people build up a tolerance to the prescription medication. 

Dr. Stone explained, “Some people, with time, may build a tolerance to the medication, a process known as tachyphylaxis, and may then require a higher dose, augmentation, or a change to a different class of stimulant to receive the same benefit as before.”

What is the standard Adderall dosage?

A standard adult dosage for Adderall can vary from person to person. Dr. Stone states this is based on a person’s age, body weight, liver and kidney function, and other medications.

On average, the standard dosage of Adderall for adults could be anywhere from 5 mg to 40 mg per day. That may be given in divided doses. This dosage would be different for a child.

An improper dosage could cause potentially dangerous consequences, which is why it is important to work with a well-trained professional when taking Adderall. It’s also important to consider additional  ADHD treatment options they may recommend, like cognitive behavioral therapy.

“Ultimately, as with most medications, it’s best to start at a low dose and to adjust accordingly based on the individual’s response and tolerability to the medication,” said Dr. Stone.

Even if you’re on the right dose, potential side effects of Adderall may include:

More serious side effects may include:

  • Uncontrollable shaking
  • Seizures
  • Heart attack and stroke
  • Increased blood pressure and heart rate
  • Psychotic symptoms

Adderall will show up on drug tests and blood tests as a stimulant drug. And there is a potential for Adderall misuse or abuse. If you will be taking a drug test, you will need to disclose and verify that you are taking a prescription stimulant under the care of medical professionals.

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Who should avoid taking Adderall?

Some individuals should avoid taking Adderall. This includes: 

  • People who are allergic to Adderall
  • People with a history of substance use disorder 
  • Those with a history of psychosis, bipolar disorder, or severe anxiety 
  • Individuals with heart problems, such as cardiovascular disease or structural heart abnormalities
  • Those with severe hypertension or serious heart arrhythmias
  • People with severe liver or kidney impairment

The bottom line

Individuals who have been prescribed Adderall typically begin feeling its effects within 30 to 60 minutes. However, this can be affected by certain foods, medications, and the dose of Adderall. Talk to your doctor about your medical history and all medications you take before starting treatment. And continue to work closely with them while you are taking this medication.