Mixed Amphetamine Salts (3:1) · Dual-Pulse Bimodal Release

Track Your Adderall XR & IR Curve

Understand the 50:50 dual-pulse bead timeline and estimate likely timing with an evidence-based population model.

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Dual-Pulse Micro-Bead Pharmacokinetics

Comparative level profiles of single-pulse Adderall IR versus dual-pulse Adderall XR.

Bimodal Extended Plateau

Adderall IR vs XR: dual-pulse XR profile after a 7 AM dose

Two curves showing Adderall IR peaking near 3 hours, while Adderall XR shows two Microtrol pulses peaking near 2.5 and 7 hours and extending into the evening 100%75%50%25%7 AM9 AM11 AM1 PM3 PM5 PM7 PM9 PMAdderall IRAdderall XR (multi-pulse)
Simplified profiles showing Adderall IR's single peak versus Adderall XR's two Microtrol pulses, with peaks near 2.5 and 7 hours. Not to clinical scale -- individual timelines vary.
10h – 3h: First Pulse (50% IR Beads)

Immediate-release beads dissolve rapidly in the stomach, providing initial peak focus between 2.5 and 3 hours post-ingestion.

24h – 8h: Second Pulse (50% Enteric)

Enteric polymer dissolves in the alkaline pH (>5.5) of the small intestine at ~4h, delivering the second wave to sustain therapeutic levels.

310h – 12h: Washout & Bedtime Threshold

Hepatic metabolism and renal clearance taper plasma levels toward the bedtime clearance zone (<15 ng/mL total amphetamine).

Amphetamine Formulations & Equivalencies

Compare the release kinetics and enantiomer ratios of standard amphetamine medications.

Brand / GenericManufacturerDelivery SystemStandard StrengthsTypical Duration
Adderall XRTakeda / Teva / Generics50:50 Dual-Pulse Micro-Beads (3:1 d/l)5, 10, 15, 20, 25, 30 mg10–12 Hours
Adderall IRTeva / GenericsImmediate Release Tablet (3:1 d/l)5, 7.5, 10, 12.5, 15, 20, 30 mg4–6 Hours
MydayisTakedaTriple-Pulse Micro-Beads (3:1 d/l)12.5, 25, 37.5, 50 mgUp to 16 Hours
Dexedrine / Zenzedi / AmfexaVariousPure Dextroamphetamine (100% d-amph)5, 10, 15, 20, 30 mg4–6h (IR) / 8–10h (Spansule)
EvekeoArbor PharmaceuticalsRacemic Amphetamine Sulfate (1:1 d/l)5, 10 mg4–6 Hours
Adzenys XR-ODTNeos TherapeuticsOrally Disintegrating XR Tablet (3:1 d/l)3.1, 6.3, 9.4, 12.5, 15.7, 18.8 mg10–12 Hours
The Acidity & Vitamin C Mechanism: GI acidity reduces initial amphetamine absorption via ion trapping. More critically, high-dose Vitamin C (ascorbic acid) acidifies urine, preventing renal tubular reabsorption and rapidly accelerating urinary excretion. Avoid high-dose Vitamin C within 2 hours of dose times.

Fast 30–45m Action

The immediate-release micro-bead fraction dissolves rapidly in gastric fluid to provide prompt morning symptom relief.

pH & Renal Kinetics

Amphetamine is an organic base. Urinary pH strongly regulates whether the drug is reabsorbed into blood or rapidly excreted in urine.

Rebound Prevention

Tracking the drop-off after the second pulse helps you anticipate the midday trough and prepare a smooth evening routine.

Caffeine Stacking with Adderall

Adderall contains 25% levoamphetamine, which inherently produces more peripheral sympathetic activation (elevated heart rate, vasoconstriction) than pure d-amphetamine. Combining caffeine with Adderall during its dual peaks substantially increases cardiovascular load, jitteriness, and restlessness.

☕ Monitor Combined CNS Exposure:Avoid large caffeine doses during the 2–3h and 6–8h peak windows to maintain calm, productive focus.
🚫 12:30 PM Cutoff:Caffeine's 5-hour half-life stacked on Adderall's evening elimination tail frequently delays sleep onset by hours.
Interactive Pharmacokinetic Engine

Simulate Your Adderall XR / IR Curve Live

Enter your dose (5mg–30mg), dose timing, and caffeine intake to calculate your exact dual-pulse plateau and bedtime clearance window.

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How FocusCurve Masters Your Adderall Day

Engineered for the dual-pulse kinetics of mixed amphetamine salts.

2-Tap Dose Logging

Log morning XR doses and afternoon IR boosters in two quick taps.

Home Screen Widget

See your dual-pulse curve progress and current therapeutic level right from your Home Screen.

Pill Inventory Countdown

Never get caught without controlled medication with smart refill reminders.

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Evidence-backed guide

Read the cited guide to Adderall IR/XR release patterns, duration, and individual variability.

How long does Adderall last? →

Methodology & Citations

Last reviewed: August 30, 2026

Curves use published pharmacokinetic parameters and normalized population averages. They estimate likely timing; they cannot predict an individual response or replace prescriber guidance.

FDA drug-label resources · Adderall XR on DailyMed

Frequently Asked Questions

How long does Adderall XR last vs IR?

Adderall XR is designed to last 10 to 12 hours via its dual-pulse micro-bead system. Immediate-release Adderall IR typically lasts 4 to 6 hours. Individual metabolic factors and urinary pH heavily influence your actual duration.

How does the 50:50 dual-pulse micro-bead mechanism work?

Each capsule contains two types of beads in equal proportion. Immediate-release beads dissolve quickly in the stomach for rapid onset. Delayed-release beads have an enteric coating that dissolves only upon reaching the alkaline pH (>5.5) of the small intestine about 4 hours later.

How do Vitamin C and acidic juices affect Adderall?

Stomach acidity reduces absorption through ion trapping. Furthermore, ascorbic acid (Vitamin C) acidifies urine, causing amphetamine molecules to become ionized in renal tubules, preventing reabsorption and rapidly accelerating urinary excretion.

What is the 3:1 enantiomer ratio?

Adderall contains a 3:1 ratio of dextroamphetamine (d-amph) to levoamphetamine (l-amph). D-amphetamine provides potent central dopamine/norepinephrine reuptake inhibition for focus, while l-amphetamine adds peripheral adrenergic activation.

How can I plan for possible afternoon rebound on Adderall XR?

FocusCurve tracks your estimated plasma curve in real time, helping you pinpoint the transition when the second bead pulse begins fading. This lets you schedule low-cognitive tasks or discuss booster timing with your doctor before symptoms rebound.

Understand Your Adderall Timeline in Total Privacy

Log doses in 2 taps, see an estimated dual-pulse curve on your Home Screen widget, and support your sleep planning.

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Medical Disclaimer: FocusCurve is an educational medication-timeline and dose-logging tool, not a medical device or diagnostic instrument. Estimated pharmacokinetic profiles are based on published population-average clinical data. Individual metabolism varies. Always consult your prescribing physician before altering your medication regimen.