When I first rebuilt my routine in Korea, I had to separate useful supplements from shiny shelf noise. There are plenty of products with aggressive labels, imported pricing, and promises that sound better than the evidence. My rule is simple: if the supplement does not solve a real problem in the plan, it does not need to be in the stack.
Protein powder is worth buying when food protein is inconsistent. It is not better than food, but it is convenient, trackable, and useful when a normal Korean meal is mostly rice, soup, noodles, or small portions of meat. If a shake helps you hit the protein target without forcing another full meal, it is doing its job.
Creatine is the easiest yes for most healthy lifters. The ISSN position stand supports creatine as one of the most effective supplements for high-intensity exercise performance and lean mass. It is not exciting because it is basic, but basic is exactly why it works. Take it consistently, do not overthink timing, and let months of training do the rest.
Caffeine can be useful, but it is where many people hurt their sleep and recovery. A pre-workout that makes one session better but ruins sleep can make the whole week worse. I prefer caffeine as a tool: use it before demanding sessions, keep the dose honest, and avoid late-day use if sleep is already fragile.
What would I skip? Most fat burners, detox products, hormone boosters, and anything built mostly on fear or hype. If your training, protein, calories, steps, sleep, and consistency are not handled, those products are a distraction. Supplements should make a good plan easier to execute. They should not become a substitute for the plan.