^ this.
People on strong psychostimulants like amphetamine tend to lose a sense of their self-awareness, and act in strange ways.
Stims can really fuck with your judgement, and while you may feel really productive, you're just hyperfocused on some minute detail of your job, but not really completing anything.
I don't know exactly what sort of work you're doing, but you could put yourself and your co-workers (and other people) if you're spun and working with heavy machinery or anything like that.
Also, speed really dehydrates you and makes you sweat and pee more. You'd likely be drinking and going off to piss constantly.
Then there's the way you'd look to your boss. you may not realise you're talking too much or too rapidly, but people pick up on that kinda thing.
Or perhaps it will lift your productivity to an unrealistic level, and your boss will expect that from you all the time.
If you can't then deliver that pace of work people might think you're slacking off, or just erratic.
Erratic is probably the most likely perception people may get - because taking speed at work will make you erratic.
You'll be very up and peppy at times, but there will be other times that you'll be tired and unable to fake enthusiasm convincingly, because speed disrupts your sleep.
I've taken stims at work before, but it's not something i'd recommend (or do again).
The one time i do take (dex) amphetamine is when i'm working in a recording studio, because i'm a musician - and it helps keep me focussed, inspired and helps maintain that focus and still play in a really nimble kind of way, even after the 17th take, 8
6 hours into the session.
But that's different, because it's not my soul source of income and i don't have a boss looking over my shoulder.
So while it is "work" but not like rocking up to my desk job all wired on speed.
Any cognitive benefits you get from amphetamine tend to balance out with how much it depletes your ability to focus the day afterwards, or when you're coming down and feeling edgy.
It's not sustainable, basically - and yeah, people on speed often tend to look like they're obviously on drugs.
I think my focus is better when i've been sleeping and eating well, and not taking too many drugs, than it is on speed.
Anyway, not wishing to sound too negative - i'm not saying "just say no" - i just think it's better to save drugs for having fun than using them to get through everyday life.
Especially amphetamine, which is physically and psychologically taxing.
I'd say it's unsafe in regards to your health, as well as OH&S and you run the risk of jeopardising your job.