ADHD Title


The biggest difference between Vyvanse and Mydayis is that they contain different active ingredients, although both are considered "amphetamine" medications. Vyvanse contains lisdexamfetamine while Mydayis contains mixed amphetamine salts, specifically amphetamine aspartate, amphetamine sulfate, dextroamphetamine saccharate, dextroamphetamine sulfate.

Below, we discuss the differences between Vyvanse and Mydayis in more detail.

Mydayis Vs. Vyvanse: Active Ingredients

Mydayis contains the same active ingredients as Adderall XR (amphetamine aspartate, amphetamine sulfate, dextroamphetamine saccharate, dextroamphetamine sulfate.), but has a different release mechanism. We wrote and in-depth article about the difference between Mydayis and Adderall XR which can be found here: Adderall XR Vs. Mydayis.

Vyvanse contains lisdexamfetamine, which is a prodrug of dextroamphetamine, meaning it gets converted in the body to that active compound. In fact, one of the main benefits of Vyvanse is that it is not easily abused as it needs to be converted to dextroamphetamine and L-lysine in the blood. If snorted, Vyvanse will have minimal effects.

In addition, due to how Vyvanse is metabolized, it is not as likely to have significant drug interactions when compared to Mydayis since liver metabolizing enzymes are not involved in the metabolism of lisdexamfetamine initially.

Some individuals have varying effects to amphetamine when compared to dextroamphetamine, but their overall mechanism of action is the same.

Mydayis Vs. Vyvanse: Release Mechanism

Mydayis is an extended-release amphetamine salt product that contains 3 types of drug beads that have different release times in the body. Mydayis contains:

  • Immediate release beads for quick effects
  • Delayed-release beads designed to release mid-day
  • Delayed-release beads designed to release even later, into the evening

Mydayis was designed to deliver a consistent dose of amphetamine salts over a longer period of time than other extended-release amphetamine products, such as Adderall XR. Mydayis is dosed once daily.

Vyvanse does not contain 3 different time release-beads but still is considered an extended-release product and is also dosed once daily. Effects of a single dose last over 12 hours, just like Mydayis.


Unfortunately, Both Mydayis and Vyvanse are available as 'brand name only' products. Generics are not yet available.

Vyvanse is scheduled to be available generically 2023 while Mydayis won't be available generically until at least 2029.

Answer Summary

  • Vyvanse and Mydayis are both extended-release amphetamine products but contain different active ingredients. Both are dosed once daily and last over 12 hours per dose.
  • Mydayis is more similar to Adderall XR, and contains the same active ingredients: Amphetamine aspartate, amphetamine sulfate, dextroamphetamine saccharate, dextroamphetamine sulfate.
  • Vyvanse contains lisdexamfetamine, which is converted in the blood to dextroamphetamine. As Vyvanse is converted to the active compound in the blood, it is not easily abused and has less drug interactions than Mydayis.

  • References
    1. Vyvanse Prescribing Information. AccessFDA
    2. Mydayis Prescribing Information. AccessFDA