I have no definitive knowledge about bringing medicine to Japan, but I have been to Japan a lot, so I have a little experience. All passengers entering Japan are interviewed one by one. Luggage is often (although indeed not always) searched, and people sometimes patted down. We are asked specifically about medicines. Once, the Customs officer was being VERY insistent, and kept pushing, even asking Not even aspirin? I had to ask him "Why, you don't have pharmacies in Japan?" to make him stop. I wouldn't tempt it with something like methamphetamine.

Definitely don’t go to Singapore.

@dda Huh, interviewed one by one? Like everyone goes into a separate room to be questioned individually? When I visited Japan last time this wasn't the case. Where was the entry airport in your case? Narita?

@justhalf you stand in line, and go one by one (or as a family/group), you put your luggage on a low counter, and a Customs officer asks you question. This may take a couple of minutes, or last a little longer, depending on whatever the officer feels like. I have been through mostly Haneda and Narita, but others too. Was the case in 1994 when I first visited, was still the case when I last visited in late 2019.

@dda I've travelled to Japan several times in the past decade, and I don't recall ever being questioned by customs. Certainly not for minutes!

@Arno They profile. Young long-haired me traveling solo: third degree every time. With Japanese wife and family: quick glance at passport and waved right through.

I hope she knows that "leaving" a Methamphetamine drug needs a careful, controlled phase-out. If there is no time for that, cancel the trip.

@stonux Not the medical SE site, but would it be safe for her to just switch to a different amphetamine-based medication (e.g. methamphetamine to Adderall or something)?

"Everyone knows" of course you can not take most ADHD drugs in to Japan. I only mention this because it's a somewhat odd question, and I would have expected that all the answers and comments would be simply "No, of course not."

@dda and lambshaanky are of course completely correct. They will find it. There's no "political correctness" in Japan, the concept doesn't exist. They simply profile and find everything. It's (by far) the safest place in the world for good reason. If you don't like that sort of thing, go to London or somewhere else instead.

@stonux people who use methamphetamine recreationally consume doses 10-50x larger than the typical prescription user and often smoke or snort it. It's not a big deal in terms of addiction for people who do what their doctor tells them.

@Fattie you have very strange ideas of what "everyone knows" and it would be great if you could occasionally stop to think "am I being spectacularly condescending?" before submitting a comment.

I have only tried Asia in general but not Japan and only prescription medicine but not methamphetamine so not an answer to your specific question. If you come from a country with electronic handling of all prescriptions, make sure you have your prescription on paper signed by your prescribing doctor.

As an ADHDer, at first I wanted to ask what drug that doctor is on to prescribe Crystal fucking Meth. For, of all things, ADHD no less. Then I googled for it and found out there's FDA approval for that. And for obesity. In adults. And children. Remind me to never, ever visit the US of A. Methylphenidate ("Ritalin") is bad enough. But meth, it kills and is certainly not suitable as a curative drug in any way, shape or form. While I empathize with OP's friend's need for help, there are other options available, perhaps from other doctors.

@Sixtyfive you're making a fallacy here of assuming that methamphetamine cannot possibly have good medicinal uses just because its also something used by drug addicts. Does this mean you'd also refuse morphine for anesthesia? After all, morphine is routinely abused by addicts!

alcohol is routinely abused by people and leads to liver cirrhosis and a bunch of other problems, doesn't mean having a glass of wine on Saturday is bad for you

the world is not black and white

you'd also be shocked to find out that fentanyl is a legitimate drug used in every major hospital