I wasn't ever a frequent user of those vitamin drinks such as Yunker, Oronamin C and Regain but once in a while when I was feeling especially fatigued, I would give in and buy one of them at the konbini to down at night or when I woke up in the morning. I never totally bought into the message that these drinks would power me up into a super working stiff but, hey, they didn't taste too bad.
From one of my students, I learned about the Japanese employee's way of getting rid of a cold fast. On getting home, the employee should take an especially hot shower then drink down a couple of bottles of the stronger (read: more expensive) vitamin drinks (how about the 3000-yen Yunker?) and then wrap himself/herself in some thick blankets and go to sleep. The effect would be that the cold would sweat itself out (my student didn't tell me about the effect on the blankets, mind you). I don't think I ever tried that particular remedy out.
In any case, those vitamin drinks had regular commercials pumped out to promote their health-remedying abilities. Of course, there was the one for Regain whose song "Yuuki no Shirushi"（勇気のしるし）became so famous that even CNN featured it.
That was back during my JET days. However, Regain wouldn't be alone in the catchy commercial jingles. There was one other song that made the rounds for several months to a year or so. Young actress Isako Washio（鷲尾いさ子）became quite the talk of the town when she was starred as the titular Tekkotsu Musume (Iron and Calcium Girl) and sang a catchy tune with the same title promoting the benefits of the drink Tekkotsu Inryo（鉄骨飲料）.
And compared to the military march that the Regain jingle was, "Tekkotsu Musume" was a mix of an old kayo boogie of the type that Shizuko Kasagi（笠置シヅ子）sang back in the 1950s and a Busby Berkeley dance performance according to the series of commercials featuring Washio. In fact, a full music video was even made (look at how genki the ladies are!). Tokyo Banana Boys（東京バナナボーイズ）were responsible for creating the tune.