How do you convert Adderall to Vyvanse?

To convert Adderall to Vyvanse, use the total daily Adderall dose (for IR, sum all daily doses). General equivalencies: Adderall XR 10 mg ≈ Vyvanse 30 mg, Adderall XR 20 mg ≈ Vyvanse 40–50 mg, Adderall XR 30 mg ≈ Vyvanse 50–60 mg, and Adderall XR 40 mg ≈ Vyvanse 70 mg. These are approximate — individual response varies due to different pharmacology (mixed amphetamine salts vs. pure d-amphetamine prodrug).

How much Vyvanse equals 20 mg Adderall?

20 mg Adderall XR is approximately equivalent to 40–50 mg Vyvanse. For Adderall IR 20 mg/day (total daily dose), the same conversion applies. The range exists because Adderall contains both d-amphetamine (75%) and l-amphetamine (25%), while Vyvanse delivers only d-amphetamine. Most clinicians start at the lower end (40 mg Vyvanse) and titrate up based on response.

What is the difference between Adderall and Vyvanse?

Adderall contains mixed amphetamine salts (75% d-amphetamine, 25% l-amphetamine) available as IR (4–6 hours) and XR (10–12 hours). Vyvanse (lisdexamfetamine) is a prodrug that converts to pure d-amphetamine after enzymatic cleavage in the blood. Vyvanse lasts 10–14 hours, has lower abuse potential due to its prodrug mechanism (cannot be snorted or injected for rapid effect), and provides smoother onset and offset.

What should I expect when switching from Adderall to Vyvanse?

When switching from Adderall to Vyvanse, expect a smoother onset (60–90 minutes vs. 30–60 minutes for Adderall IR) and longer duration of action. Some patients notice less 'peak and crash' effect. The switch is typically done overnight — take the last Adderall dose as usual, then start Vyvanse the next morning. Titration over 1–2 weeks may be needed to find the optimal Vyvanse dose, as there is no exact 1:1 equivalence.

Can you convert Vyvanse back to Adderall?

Yes. Reverse conversion: Vyvanse 30 mg ≈ Adderall XR 10 mg, Vyvanse 50 mg ≈ Adderall XR 20–25 mg, Vyvanse 70 mg ≈ Adderall XR 30–40 mg. When converting from Vyvanse to Adderall IR, split the equivalent daily dose into 2–3 doses given 4–6 hours apart. Always titrate carefully — individual responses differ due to the different amphetamine salt compositions.

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Home / Adderall to Vyvanse Conversion

Adderall to Vyvanse Conversion Calculator

Convert between Adderall (mixed amphetamine salts) and Vyvanse (lisdexamfetamine) doses. Supports IR and XR formulations with evidence-based conversion ratios.

Stimulant Conversion

Conversion Direction

Adderall Formulation

For Adderall IR, enter the total daily dose (sum of all daily doses).

Adderall Dose (mg/day)

Or enter custom dose

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Select a dose to see the conversion.

⚠️ Important: These conversions are approximate. Individual response varies significantly. Always titrate to clinical effect. This is not an exact 1:1 conversion.

Disclaimer: For educational purposes only. Not a substitute for clinical judgment.

When to use

Use this calculator when switching between Adderall (mixed amphetamine salts) and Vyvanse (lisdexamfetamine) for ADHD or binge eating disorder. Helpful for dose estimation during medication transitions.

Key Differences

Adderall — Mixed amphetamine salts: 75% d-amphetamine, 25% l-amphetamine. Available as IR (4–6 hr) and XR (10–12 hr).

Vyvanse — Lisdexamfetamine dimesylate, a prodrug. Enzymatically cleaved to d-amphetamine in the blood. Duration 10–14 hr. Lower abuse potential (cannot be snorted/injected for rapid effect).

Clinical Pearls

Vyvanse delivers only d-amphetamine — patients relying on l-amphetamine effects may respond differently.
Vyvanse onset is slower (60–90 min) but smoother than Adderall IR.
Start at the lower end of the equivalent range and titrate up over 1–2 weeks.
The switch can typically be done overnight — last Adderall dose as usual, start Vyvanse the next morning.
Vyvanse capsules can be opened and dissolved in water for patients who cannot swallow capsules.

Conversion Reference Table

Adderall XR	Vyvanse
5 mg	20 mg
10 mg	30 mg
15 mg	30–40 mg
20 mg	40–50 mg
25 mg	50 mg
30 mg	50–60 mg
40 mg	70 mg

Available Strengths

Adderall IR: 5, 7.5, 10, 12.5, 15, 20, 30 mg tablets

Adderall XR: 5, 10, 15, 20, 25, 30 mg capsules

Vyvanse: 10, 20, 30, 40, 50, 60, 70 mg capsules (also chewable)

References

Vyvanse (lisdexamfetamine dimesylate) prescribing information. Takeda Pharmaceuticals. 2023.
Goodman DW. Lisdexamfetamine dimesylate (Vyvanse), a prodrug stimulant for ADHD. P T. 2010;35(5):273-287.
Biederman J, Boellner SW, Childress A, et al. Lisdexamfetamine dimesylate and mixed amphetamine salts extended-release in children with ADHD. Clin Ther. 2007;29(3):450-463.
Adderall XR (mixed amphetamine salts) prescribing information. Teva Pharmaceuticals. 2023.

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About This Calculator

Adderall vs. Vyvanse: Understanding the Pharmacology

Adderall (mixed amphetamine salts) contains a 3:1 ratio of d-amphetamine to l-amphetamine as a mixture of amphetamine aspartate monohydrate, amphetamine sulfate, dextroamphetamine saccharate, and dextroamphetamine sulfate. The d-isomer is the more pharmacologically potent CNS stimulant, while the l-isomer contributes more to peripheral sympathomimetic effects. Adderall IR reaches peak plasma concentration in approximately 3 hours and lasts 4–6 hours, while Adderall XR uses a bead delivery system to achieve an initial peak at ~3 hours and a second peak ~7 hours after dosing, lasting 10–12 hours.

Vyvanse (lisdexamfetamine dimesylate) is a prodrug — the amino acid lysine is covalently bonded to d-amphetamine. After oral ingestion, lisdexamfetamine is absorbed intact, then enzymatically cleaved by red blood cell aminopeptidases to release active d-amphetamine. This rate-limited conversion provides a smooth pharmacokinetic profile with peak plasma levels at approximately 3.5–4.5 hours and duration of 10–14 hours. Because the prodrug mechanism limits the rate of d-amphetamine release regardless of the amount ingested, Vyvanse has a lower abuse potential compared to immediate-release amphetamine formulations.

Why Conversion Is Not Exact

Several factors make Adderall-to-Vyvanse conversion inherently approximate:

Different active moieties: Adderall provides both d-amphetamine and l-amphetamine, while Vyvanse delivers only d-amphetamine. Patients may respond differently to the absence of l-amphetamine.
Prodrug conversion efficiency: Approximately 29.5% of lisdexamfetamine's molecular weight is active d-amphetamine (after enzymatic cleavage). Thus, a 70 mg Vyvanse capsule delivers approximately 20.6 mg of d-amphetamine.
Different pharmacokinetic profiles: Even at equivalent d-amphetamine exposure, the rate of absorption, peak concentrations, and duration differ between formulations.
Individual variability: Enzyme activity, pH, body composition, and genetics all affect drug metabolism differently for each formulation.

Titration Guidance

When switching from Adderall to Vyvanse, most experts recommend starting at the lower end of the equivalent dose range and titrating upward in increments of 10 mg per week until optimal efficacy is achieved with acceptable side effects. The maximum recommended dose of Vyvanse is 70 mg/day for ADHD in adults and children ≥6 years. For binge eating disorder (BED) in adults, the recommended dose is 50–70 mg/day.

🔑 Clinical Pearls for Switching

The switch can be done abruptly — take the last Adderall dose as scheduled, then start Vyvanse the next morning. No taper is needed.
Vyvanse should be taken in the morning; afternoon dosing may cause insomnia due to its long duration.
If a patient was well-controlled on Adderall XR 20 mg, starting Vyvanse at 40 mg (lower end of the 40–50 mg range) is a reasonable approach.
Monitor for both under-treatment (return of ADHD symptoms) and over-treatment (anxiety, insomnia, appetite suppression) during the first 2 weeks.
Heart rate and blood pressure should be monitored at baseline and during titration, as with all stimulant medications.

D-Amphetamine Content Comparison

Medication	Total Dose	d-Amphetamine Content
Adderall 20 mg	20 mg mixed salts	~15 mg d-amp + ~5 mg l-amp
Vyvanse 50 mg	50 mg lisdexamfetamine	~14.8 mg d-amp (29.5%)
Vyvanse 70 mg	70 mg lisdexamfetamine	~20.6 mg d-amp (29.5%)

Key References

Vyvanse (lisdexamfetamine dimesylate) prescribing information. Takeda Pharmaceuticals America, Inc. Revised 2023.
Goodman DW. Lisdexamfetamine dimesylate (Vyvanse), a prodrug stimulant for attention-deficit/hyperactivity disorder. P T. 2010;35(5):273-287.
Biederman J, Boellner SW, Childress A, Lopez FA, Krishnan S, Zhang Y. Lisdexamfetamine dimesylate and mixed amphetamine salts extended-release in children with ADHD: a double-blind, placebo-controlled, crossover analog classroom study. Biol Psychiatry. 2007;62(9):970-976.
Ermer JC, Pennick M, Engel G. Pharmacokinetics of lisdexamfetamine dimesylate after targeted gastrointestinal release versus intact capsule. Drug Metab Pharmacokinet. 2011;26(6):626-633.
Heal DJ, Smith SL, Gosden J, Nutt DJ. Amphetamine, past and present — a pharmacological and clinical perspective. J Psychopharmacol. 2013;27(6):479-496.

Formula last verified: February 2026