How much dextroamphetamine is in Adderall?

October 9, 2025 •

3 min read

Adderall is a combination of four different amphetamine salts, formulated in a precise 3:1 ratio of dextroamphetamine to levoamphetamine isomers. This unique composition means the exact amount of dextroamphetamine is dependent on the total dosage of the Adderall tablet or capsule. The 'd-' isomer, or dextroamphetamine, is a more potent central nervous system stimulant than the 'l-' isomer, or levoamphetamine, which has milder effects.

Quick Summary

Adderall's composition features a 3:1 ratio of dextroamphetamine to levoamphetamine salts. The total drug dose dictates the exact milligram amount of each amphetamine component. This combination provides both immediate and extended stimulant effects for treating ADHD and narcolepsy.

Key Points

Precise 3:1 Ratio: Adderall contains a mix of amphetamine salts with a 3:1 ratio of dextroamphetamine to levoamphetamine.
75% Dextroamphetamine: Based on the 3:1 ratio, dextroamphetamine makes up 75% of the total amphetamine content in any given dose.
Varies by Total Dose: The specific milligram amount of dextroamphetamine depends on the total dosage of the Adderall tablet or capsule prescribed.
IR vs. XR Delivery: The amount of dextroamphetamine is the same across IR and XR formulations of the same total dose, but the release mechanism differs.
Potency and Duration: Dextroamphetamine provides stronger central nervous system effects, while levoamphetamine offers milder, more prolonged peripheral and cardiovascular effects.
Total Amphetamine Salts: The dosage listed on Adderall (e.g., 20 mg) refers to the total weight of all four amphetamine salts combined.
Not a Single Molecule: Adderall is a combination drug, not pure dextroamphetamine, which is important for understanding its overall effects and profile.

Adderall's Amphetamine Composition

Adderall is a combination medication containing four different amphetamine salts: dextroamphetamine saccharate, dextroamphetamine sulfate, amphetamine aspartate monohydrate, and amphetamine sulfate. These salts are combined in a specific 3:1 ratio of dextroamphetamine to levoamphetamine. This blend of isomers provides both rapid and sustained stimulant effects.

Both dextroamphetamine and levoamphetamine increase levels of norepinephrine and dopamine in the central nervous system, but they differ in potency and duration. Dextroamphetamine is a more powerful stimulant with stronger CNS effects, while levoamphetamine has a longer half-life and more peripheral and cardiovascular effects. This combination aims to provide a balanced therapeutic effect for conditions like ADHD and narcolepsy.

Calculating the Dextroamphetamine Content by Dosage

Due to the consistent 3:1 ratio, dextroamphetamine constitutes 75% of the total amphetamine salt content in any Adderall dose. To determine the amount of dextroamphetamine in a specific dose:

Formula for calculating dextroamphetamine

Identify the total dose of the Adderall tablet or capsule.
Multiply the total dose by 0.75.

For example, if the total dose is 20 mg, the calculation is 20 mg * 0.75 = 15 mg. This means a 20 mg Adderall contains approximately 15 mg of dextroamphetamine salts and 5 mg of levoamphetamine salts. The total milligram dosage on the label refers to the combined weight of all four active amphetamine salts.

Adderall IR vs. Adderall XR: Dextroamphetamine Delivery

Both Immediate-Release (IR) and Extended-Release (XR) formulations of Adderall maintain the 3:1 dextroamphetamine to levoamphetamine ratio for a given total dose. The key difference lies in how the medication is released over time.

Adderall IR tablets release the full dose of amphetamine salts quickly, providing effects for about 4 to 6 hours.

Adderall XR capsules utilize a bead-based system, with half the dose releasing immediately and the other half delayed for about four hours. This provides a longer-lasting effect, typically up to 12 hours.

The Role of Dextroamphetamine and Levoamphetamine

The combination of dextroamphetamine and levoamphetamine is designed to leverage their distinct pharmacological profiles. Dextroamphetamine is primarily responsible for the central effects like improved focus, while levoamphetamine contributes to the overall duration of action and peripheral effects. This differs from medications containing only dextroamphetamine, such as Dexedrine. The blend in Adderall helps achieve smoother and more sustained symptom management for conditions like ADHD and narcolepsy.

Conclusion

Adderall contains a precise 3:1 ratio of dextroamphetamine to levoamphetamine salts. Dextroamphetamine consistently makes up 75% of the total amphetamine content, with the exact milligram amount varying by the total prescribed dose. This specific blend, combined with the different release profiles of IR and XR formulations, allows for individualized treatment approaches. As a Schedule II controlled substance with potential for abuse, it is essential to consult with a healthcare professional for accurate information and guidance.

The Importance of Professional Guidance

Understanding Adderall's composition is valuable, but it is critical to rely on professional medical advice for proper dosage and treatment plans. A physician will consider individual factors to determine the appropriate prescription. This information is for educational purposes and not a substitute for consulting with a qualified healthcare provider. Do not adjust medication or dosage without professional supervision.

MedlinePlus: Dextroamphetamine and Amphetamine Information

Frequently Asked Questions

Adderall is a combination medication containing a mix of dextroamphetamine and levoamphetamine salts, while dextroamphetamine is a single, more potent amphetamine isomer. The combination in Adderall provides both immediate and sustained effects.

Yes, for the same total milligram dosage (e.g., 20 mg IR vs. 20 mg XR), both formulations contain the same amount of active ingredients. The difference is in the release mechanism, which affects how quickly the medication enters the bloodstream.

The 3:1 ratio means that for every four parts of amphetamine salts in Adderall, three parts are the dextro isomer (dextroamphetamine) and one part is the levo isomer (levoamphetamine).

To calculate the amount, take your total Adderall dose and multiply it by 0.75. For example, a 10 mg tablet contains approximately 7.5 mg of dextroamphetamine (10 mg x 0.75).

Yes, dextroamphetamine is a more potent central nervous system stimulant compared to levoamphetamine. Levoamphetamine has a longer half-life and contributes to the overall effect with milder cardiovascular and peripheral stimulation.

The combination of amphetamine salts in Adderall is designed to provide a more balanced clinical effect. It includes both immediate-release and longer-lasting components to effectively manage ADHD and narcolepsy symptoms.

No, Adderall does not contain methamphetamine. While both belong to the stimulant class and are chemically related, they have distinct chemical structures and are different drugs.