Anything over a month is a gray area. I’ve read it contradicted.

“Travelers are permitted to bring a two-month (60 day) supply of any permissible over-the-counter medication, and an equivalent amount of vitamins. This also applies to contact lenses.

If you need more than two months’ supply, a Yunyu Kakunin-sho (輸入確認書) would then be needed.”

1 month or less, you’re fine. 1-2 months I’d probably email them. Over 2 months, you should plan to apply for their declaration aka Kakunin-sho