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What Adderall actually is
Adderall is a brand name for a combination of four amphetamine salts: 75% dextroamphetamine and 25% levoamphetamine. First FDA-approved for ADHD in 1996, the generic is called "mixed amphetamine salts" (MAS).
It comes in two forms:
- Adderall IR (immediate-release): Takes effect in 30-60 minutes. Duration typically 4-6 hours. Usually dosed two to three times daily.
- Adderall XR (extended-release): Uses a bead delivery system - 50% dissolve immediately, 50% dissolve 4 hours later. Duration approximately 10-12 hours from a single morning dose.
For a detailed comparison of these two forms, see Adderall XR vs IR differences.
How it works in the brain
Amphetamines increase the availability of two neurotransmitters: dopamine and norepinephrine. They do this through multiple mechanisms, which is what distinguishes them from methylphenidate-based medications like Ritalin.
Specifically, amphetamines:
- Enter the nerve terminal through the dopamine transporter (DAT) and norepinephrine transporter (NET)
- Reverse the direction of these transporters, pushing dopamine and norepinephrine out of the neuron into the synapse
- Inhibit vesicular monoamine transporter 2 (VMAT2), releasing stored dopamine from vesicles
- Weakly inhibit monoamine oxidase (MAO), the enzyme that breaks down dopamine
A landmark PET imaging study by Volkow et al. (2009) demonstrated that people with ADHD have reduced dopamine receptor and transporter availability in key brain regions. Amphetamines compensate by increasing dopamine signaling in the prefrontal cortex.
Heal et al. (2013) in the Journal of Psychopharmacology described how therapeutic doses produce a slow, sustained dopamine increase - neurochemically different from the rapid spike seen in misuse.
Dose-by-dose: what each strength typically does
Dosing is highly individual. These are general clinical patterns from prescribing data and titration studies - your experience may differ significantly. Your prescriber adjusts based on your response, not population averages.
| Dose (IR) | Typical Clinical Use | Notes |
|---|---|---|
| 5 mg | Starting dose for adults and children. Used to assess initial response and tolerability. | Many adults notice minimal effect here. That's expected - it's a test dose, not a therapeutic target. |
| 10 mg | Common first therapeutic dose for adults. Many people begin noticing improved focus and task initiation. | Often where "oh, this is what it feels like" happens. Side effects usually mild at this level. |
| 15 mg | Mid-range dose. Often the target for adults with moderate symptom severity. | Appetite suppression and sleep effects become more noticeable for some. |
| 20 mg | Common therapeutic dose for adults. Strong focus improvement for most responders. | The point where side effect management (eating, sleep) often becomes important. |
| 25-30 mg | Higher end of typical adult dosing per administration. Some adults need this level. | Diminishing returns may start here for some. More isn't always better. |
| Dose (XR) | Roughly Equivalent To | Notes |
|---|---|---|
| 10 mg XR | 5 mg IR twice (5mg now + 5mg in ~4h) | Starting dose. Mild effect. |
| 20 mg XR | 10 mg IR twice | Common starting therapeutic dose for adults. |
| 30 mg XR | 15 mg IR twice | Solid mid-range adult dose. |
| 40 mg XR | 20 mg IR twice | Higher range. Above the 20 mg/day the label recommends for adults; used only when a prescriber judges it necessary. |
Dose conversions are done by your prescriber, not by you — don't switch or adjust doses on your own.
FDA labeling for Adderall XR recommends 20 mg once daily for adults. For adolescents (13-17), the label notes no clear added benefit above 20 mg/day, and for children 6-12 the maximum is 30 mg/day. The Adderall IR label notes that only in rare cases is it necessary to exceed 40 mg/day. Higher dose does not always mean better response: pushing past the optimal dose often adds side effects without additional benefit. Any dose change should come from your prescriber.
The "right" dose is the lowest dose that produces meaningful symptom improvement with tolerable side effects. Titration typically takes 2-6 weeks.
Adderall vs Vyvanse dose equivalence
These medications aren't directly equivalent milligram-for-milligram because Vyvanse is a prodrug that converts to only dextroamphetamine, while Adderall contains both dextro- and levo-amphetamine. Approximate clinical equivalences used by prescribers:
| Vyvanse | Approximate Adderall XR Equivalent | Active d-amphetamine Delivered |
|---|---|---|
| 20 mg | ~7-8 mg XR | ~5.9 mg d-amph |
| 30 mg | ~10-12 mg XR | ~8.9 mg d-amph |
| 40 mg | ~15-17 mg XR | ~11.8 mg d-amph |
| 50 mg | ~20-22 mg XR | ~14.8 mg d-amph |
| 60 mg | ~25-27 mg XR | ~17.7 mg d-amph |
| 70 mg | ~30 mg XR | ~20.7 mg d-amph |
These are approximations. Adderall XR's levo-amphetamine component contributes additional noradrenergic effects not captured in a pure d-amphetamine equivalence. Individual conversion ratios may differ. See Adderall vs Vyvanse comparison.
Dose conversions are done by your prescriber, not by you — don't switch or adjust doses on your own.
What the research shows about effectiveness
A large-scale network meta-analysis by Cortese et al. (2018) in The Lancet Psychiatry (133 trials, 10,000+ participants) found amphetamines were the most effective pharmacological treatment for adult ADHD. Effect sizes of 0.7-0.9 are considered large in clinical research. Approximately 70% of adults with ADHD respond to stimulant medication.
Common experiences
- Improved task initiation. Not "motivation" - more like the removal of a barrier. See why starting is the hardest part.
- Better working memory. Holding multiple pieces of information simultaneously may improve (Bedard et al., 2007).
- "Why does Adderall make me calm?" By increasing dopamine to more typical levels in the prefrontal cortex, the brain stops seeking stimulation through restlessness. You're not sedated - your brain is no longer under-stimulated.
Side effects
- Appetite suppression (33% in adult trials) - most pronounced in first weeks. See medication and food.
- Insomnia (27% in adult trials) - see ADHD sleep strategies.
- Increased heart rate - on average about 3-6 bpm across CNS stimulants (FDA prescribing information). Report palpitations or chest pain to your prescriber.
- The "crash" - rebound as medication wears off. See when meds wear off.
Interactions
- Vitamin C and other acidifying agents: The label says acidifying agents lower amphetamine blood levels. It gives no dose threshold or waiting time; see our label-by-label food guide.
- Caffeine: Additive stimulant effects. See coffee and ADHD meds.
- Cannabis: Can impair attention and memory and makes it harder to judge how well your medication is working. Discuss with your prescriber. See ADHD and cannabis.
- MAOIs: Contraindicated. Hypertensive crisis risk.
Supplements with ADHD research
- Magnesium (glycinate/threonate): Lower levels found in ADHD (Effatpanah et al., 2019). See magnesium and ADHD.
- Omega-3 (EPA): Small but significant effect (Chang et al., 2018). See omega-3 and ADHD.
- Iron: Only supplement if blood test confirms deficiency.
- Vitamin D: Lower levels in ADHD populations. Mixed supplementation results.
None of these replace medication. Discuss with your doctor, as some may interact with your prescriptions.
References
- Cortese et al. (2018). Comparative efficacy of ADHD medications. The Lancet Psychiatry, 5(9), 727-738.
- Volkow et al. (2009). Dopamine reward pathway in ADHD. JAMA, 302(10).
- Heal et al. (2013). Amphetamine, past and present: a pharmacological and clinical perspective. J Psychopharmacol, 27(6), 479-496.
- Adderall XR prescribing information. Takeda Pharmaceuticals. FDA label (DailyMed).
- Effatpanah et al. (2019). Magnesium status and ADHD: a meta-analysis. Psychiatry Research, 274, 228-234.
- Chang et al. (2018). Omega-3 meta-analysis. Neuropsychopharmacology, 43(3).