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

  5. I am 32 years old and have tried several adhd meds and like vyvanse the best, but it’s far from perfect. I’m on 70 mgs and I take it around 7 am every morning. It seems to start working two hours later, but around 2pm every day I get very drowsy. I’m talking drowsy to the point I could probably fall right asleep if I laid down. If I drink a small cup of coffee, that seems to help and I can quickly refocus. My focus lasts until about 6pm, but I still feel less a little effect until 8pm or so.

    The mid-day tiredness is really odd and annoying. I haven’t been able to find much online about others with this issue–I would love to know if it is just me. I don’t have that problem when I’m not taking it.

    Overall I really like vyvanse. I’m able to focus, but not laser focus like adderall, and without the jitters. I forget that I’m taking it until I get the mid day drowsyness, but I still don’t feel like I’m “on something”.

    • Bianca: I’m in the exact same boat as you: 70mg vyvanse at around 7 am (have a job as a radiographer.) It always works by the second hour after ingestion, and I usually start to feel very drowsy between 12:00-15:00ish, and it persists until I can nap a little or at least rest for a while and maybe eat something. Then I seem to have a period where I am a little better, but in general I am just looking forward to sleeping in when night comes after that. I am about 230lbs male, and I suspect my dose is too low. The mid-day naps feels like they would be avoidable if I could up the dose and maybe extend the period before tiredness sets in until after at least 12 hours or so after it starts working in the morning, so I can get to bed at night and fall asleep right away instead of messing up my sleeping-pattern with naps

  6. F/24/Quebec

    I’ve been using vyvanse for a couple months now,
    My whole life i went on without any medication but always had the same problems happening over and over. Anyways as an adult i decided to give myself a break and try. I originaly started with 10mg and went up gradually, now i just started 40mg.

    My jaw locks, my hearts races, im feeling hot/cold, constant feel for a smoke, thirst and a lack of appetite.

    If any parent is reading this considering it for their child, please don’t !
    It’s just like cocaine without the fun, i used to use recreationally.

    It’s difficult to manage, i don’t know what to expect as far as, how much can this VYVANSE can actually help with. My doctor is asking me, is 40mg seems enough. if i need a higher dose? I’m afraid that the side effect would also increase. But also temptted to say yes because, as you can see, i still find it hard to get to the point lol
    I still act spontaniously and cant control my excessive speach… Any thoughts?


  7. I have been on Vyvanse for about 2-3 months now and it seems to work for me only if I am still on Adderall which I am on 30mg Adderall. I know that I shouldn’t be on both but I can only function if I take 30mg of Adderall and 50mg of Vyvanse. On top of my other medications that I am on, like my anxiety medication. Then I am good all day at work and at home because I tend to get stuff done. I feel like myself when I am on both medications. My brain can’t seem to know the difference in stopping Adderall and trying Vyvanse by itself. I just can’t seem to come to terms with it. Because I don’t know which one works best for me.

  8. I started 30 mg Vyvanse about a month a go. The first few days I did get the dry mouth, but did not get racing heart or jitters like I used to get on Adderall. It is very smooth and gentle in comparison, and not a “high” type feeling for me. But it does start to wear down around noon. I hate to have to take a 2nd dose during the day, but I go back to the dr in a week or so to talk about how it is working for me. I will see what he suggests whether it is a higher dose or maybe a booster dose, or maybe I am just SOL.

  9. I am a 54 yr. old woman who was just diagnosed. I am started on 10mg. today and it helped me. I took it at about 10:30am. However, now it is almost 9pm and I am eating like crazy. I judt had 4 applecider powered donuts. I have been working so hard to loose weight and I cannot have this happen to me. I lived this long without vyanse, I would rather not take it and be in better physical health thatn take it, focus but be fat.

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