Vyvanse in Adults: 14 Hours

A study was recently published which demonstrated that Vyvanse (lisdexamfetamine dimesylate) works up to 14 hours in adults with ADD/ADHD.

In this study, measurements of adult ADD/ADHD symptom control were taken at 2 hours post medication, and were found to be effective all the way to 14 hours after the medication was taken.

This can be important for adults with ADD/ADHD who need to have good symptom control throughout the day – to take care of many responsibilities through the day, including family and work responsibilities.

Based on this study – the FDA has allowed for a labelling change for Vyvanse – so that the product monograph allows for documentation of the 14 hour duration of Vyvanse in adults.

I’m curious to hear adults’ experiences with Vyvanse. Does it last up to 14 hours for you? Does it take 2 hours to start working? Please share your comments below.


Dr. Kenny


  1. I am 21/female/5 foot and 135 pounds

    I started on 20mg of Vyvanse in June I believe ? My doctor said we would up it once I was back in college (September) but my next appointment isn’t until October 7th .

    Once I was back in school I noticed the 20mg was doing nothing at all to help me… (Didn’t notice before because I wasn’t working and had nothing to concentrate on). So (and I don’t recommend this) I upped my does to 40 mg with extra pills I had and this made a slight difference but not much… I am in an advnaced accounting program and good grades are a must ! I’m scared he won’t up it enough… I don’t feel 40mg will be high enough (BTW not trying to get high with my meds just wanna be able to focus !). I am scared to ask for a higher than 40mg dose fearing the doc will think I am trying to abuse…

    Some side effects I have from it are extreme dry mouth… Teeth grinding and jaw clenching that causes headaches and twitching lol oh and loss of appetite.

  2. Oh, it does NOT and never has worked 14 hours for me. Most would’ve been 9. It is anywhere from 4-9 with 6-7 being most common.

  3. I have been on vyvanse since I was 5 or 6 years old. I was placed on 50mg and as I began to get older the amount has a little more than doubled. I’m now 18 and on 80mg of vyvanse and it does usual take up to 1(1/2) to 2 hours to finally start working throughout my system. It last up to at the most 10 hours. If you are new to this prescription I’d advice you to talk to your doctor and see what dose works best for you and when the best time to take it is.

    I’m currently on other medications and happen to become very familiar with other medicines and pain killers due to health issues and visits to the hospital. If you have any questions that you feel need to be answered or want to be answered you may reach me at marnitawilliams97@gmail.com or (901)-296-1469.

  4. I’ve been taking vyvanse 40mg for a couple months now, I can’t seem to find any sleep. Even if I take it at 8am, it will last until 4am

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