Every year that my wife goes back to Indonesia on an extended visit, her relatives and close friends make a list of supplements to bring for oleh-oleh. The most popular are multivitamins and omega-3, like Centrum Silver and 1000mg fish oil from Costco or WalMart. Invariably she ends up bringing about 10 bottles of these items, and then asks me to bring more, when I go down to meet back up with her. So far we've never been questioned at CGK customs for these kinds of things.
I always found it interesting that she gets these requests. So last year I spent a fair amount of time in several malls from Solo to Semarang, going to Hypermart, Carrefour, GNC, and any other little apotiks I could find in these places. I found that you could actually find similar quality items - especially at GNC, but typically at much higher prices. This not only included vitamins and supplements, but also to workout powders like whey protein. The most notable example was Optimal Nutrition (ON) whey protein isolate. Workout proteins are something I've been using with success for some number of years, however ON is not my favorite, but will due in a pinch. I would pay about $40-$45 for a large container here in the US, but was able to find the exact same thing there (at only one high end mall apotik) for IDR 1.600.000 (or about $110). From that, I then spent time looking at the backs of various supplements to find that most off-the-shelf supplements were at greatly reduced quantities or strengths, and the prices seemed to be similar or more than what's found in the USA for the amount you receive. Then there's the question of quality, which I cannot comment on, as I've not used the Indonesian brands. However, that might likely change, if I end up living there more permanently (i.e. not going back and forth so often). Bringing large tubs of protein powders on a replenishment trip from the US, might attract a little more attention from Indonesian customs.
Ironically, I buy most of my supplements and workout stuff from Amazon. From what I've read on this forum for the past couple years is that Amazon shipments - especially with things like supplements may not make it through. If that's the case, I would have to come up with a new plan for this area of my lifestyle.