Vyvanse is just DextroAmphetamine once processed in your body - AKA Speed in terms of slang drug usage. AFAIK, it’s just that no matter what the dosage, the drug dispenses itself/processes in your body based on a few factors, & is always that amount being continuously released over time.

I guess if you’re arguing (I know you are not, I am just putting unsolicited info out) in terms of what amphetamines are the worst… methamphetamine, pharmaceutical grade & at the equivalent therapeutical dosage for ADHD symptoms - which is something like 5mg-15mg max, & potentially up to 45mg for the very worst cases of chronic fatigue syndrome - is actually less hard than others on your body from a neurotoxicity standpoint, as well as on your vascular system in general. You can also very easily take naps on it (at those dosages).

It just happens to be highly addictive because of the whole blood brain barrier crossing thing. & then once you get out of that therapeutic dosage into “recreational/abusive” dosages… that is when meth is very bad.

So if you don’t have an addictive personality & can control yourself, prescribed methamphetamine (Desoxyn, not sure if a generic exists) is otherwise the safest treatment for ADHD if expected to be consistently on it for decades/life.

I believe it then goes

DextroAmphetamine

50:50 Racemic Amphetamine (Evekeo may be brand for this in US?)

Adderall (which is 3:1)

From least harm on your body to most harm over time.

My doc & I for the time being found Vyvanse was nearly perfect for me, & essentially perfected it by adding a small (10mg) instant-release DextroAmphetamine (Zenzedi, specifically branded - seems to be the most perfected formulation in the US pharmacy system as of now.) along with it to kickstart things in the morning. There are also times when I’m scripted to just take multiple 10mg IRs a day instead of the entire Vyvanse dosages for other medical reasons & potential need to rest. Mentioning rest: a non-negligible portion of people on an otherwise perfectly working Vyvanse dosage seem to need a mild-moderate sleep aid towards the end of the day. & where you may think that just indicates a lowering of the dosage, that is mostly wrong & ruins the “otherwise perfectly working” aspect.

I only mention all of this unsolicited advice/information as I’ve for far too long now, & with medical practitioners in family, seen anecdote after anecdote of people prescribed Adderall (IR or ER) eventually trying pure DextroAmphetamine IR (previously known as Dexedrine, now Zenzedi, & of course generic) - or ER like Vyvanse - & finding that it works much, much better than Adderall. Typically from a standpoint of less irritability/jitteryness/emotional blunting & more focus & ability to change task to task if needed. For whatever reason though (obviously, industry money slushing around related), Adderall is prescribed at a ridiculously higher rate than pure DextroAmphetamine. There’s also a decent amount of people who’ve only heard the term Adderall & don’t know DextroAmphetamine exists. Finally, that in some rare cases, meth is genuinely the correct drug for treatment. I honestly think if you’re being prescribed an amphetamine, doctors should have to inform you of all amphetamine based medication able to be prescribed for your condition & the potentially pros/cons comparisons - but I am nobody in this world.