The average prescribed dose of Adderall for adults with ADHD is 20 mg per day. But that number only tells part of the story, because the right dose varies by age, which formulation you take, and how your body responds. Prescribed daily doses range from as low as 5 mg to as high as 40 or 60 mg depending on the condition being treated.
Standard Doses for ADHD by Age
Adderall dosing follows a stepped approach, starting low and increasing weekly until symptoms improve. The FDA doesn’t base dosing on body weight. Instead, doses are adjusted based on how well symptoms respond and how the medication is tolerated.
For the extended-release version (Adderall XR), the recommended doses break down by age group:
- Children ages 6 to 12: Start at 10 mg once daily in the morning, with increases of 5 to 10 mg per week. The maximum recommended dose is 30 mg per day.
- Adolescents ages 13 to 17: Start at 10 mg daily, with the option to increase to 20 mg after one week if symptoms aren’t well controlled.
- Adults: The recommended dose is 20 mg per day.
For the immediate-release version (Adderall IR), children 6 and older typically start at 5 mg once or twice daily, increasing by 5 mg each week. The FDA notes that it’s rarely necessary to exceed 40 mg per day for ADHD in this age group. Younger children between ages 3 and 5 start even lower, at 2.5 mg daily, with smaller 2.5 mg weekly increases. Adderall XR has not been studied in children under 6.
How IR and XR Differ in Practice
The immediate-release tablet hits peak levels in your bloodstream about 3 hours after you take it and wears off relatively quickly, which is why it’s often taken two or three times a day. The extended-release capsule reaches its peak around 7 hours after dosing and is designed to last through the day with a single morning dose.
A 20 mg XR capsule delivers roughly the same total drug exposure as taking two 10 mg IR tablets spaced about 4 hours apart. So if you’re comparing doses between the two, a single XR dose replaces two IR doses at half the strength each. This matters when switching between formulations, because the numbers on the label won’t match up one-to-one.
Doses for Narcolepsy
When Adderall is prescribed for narcolepsy rather than ADHD, the dose range is wider. Adults typically start at 10 mg daily and can go up to 60 mg per day, taken in divided doses throughout the day. The first dose is taken in the morning, with additional doses spaced every 4 to 6 hours. Only the immediate-release form is used for narcolepsy; Adderall XR is not approved for this condition.
Why Your Dose May Be Higher or Lower
Two people with the same diagnosis can end up on very different doses. The FDA’s guidance is explicit: dosing should be individualized based on each patient’s response, using the lowest dose that works. Several factors play into where you land.
One is genetics. Your liver uses a specific enzyme called CYP2D6 to break down amphetamine. Some people carry gene variants that make this enzyme less active, which means the drug stays in their system longer and hits harder at the same dose. The FDA’s pharmacogenomic guidance suggests that people who are “poor metabolizers” of this enzyme may need a lower starting dose or a different medication altogether. Population-wide variations in this enzyme are common enough that they likely explain some of the range in effective doses.
Other factors include how severe your symptoms are, whether you’ve taken stimulant medications before, and how sensitive you are to side effects like appetite loss, insomnia, or increased heart rate. Someone who’s been on stimulants for years might be on a stable dose of 30 or 40 mg, while a new patient might find 10 mg sufficient.
How Dose Adjustments Work
Adderall is almost never prescribed at a fixed dose from day one. The standard process is called titration: you start at a low dose and increase it in small steps, usually once per week, until you and your prescriber find the level that controls symptoms without causing too many side effects. For Adderall XR in children, those steps are typically 5 or 10 mg at a time. For adolescents, it’s often a single jump from 10 to 20 mg after one week.
This process can take several weeks. It’s also not purely one-directional. If a dose increase causes problems like jitteriness, difficulty sleeping, or a racing heart, stepping back down is common. The goal is always the lowest effective dose, not a target number. There’s no “normal” dose that everyone should aim for, and being on a lower dose doesn’t mean your ADHD is less real or less severe.