Surely you work out at the gym for a specific purpose. Of course, exercise can give you pleasure or be a tool to reduce stress and tension, but with its help you usually want to take care of yourself and your appearance, thus also improving your self-esteem. The effects will not come out of thin air. They will come from both exercise and diet. And in turn the diet itself, even the best balanced and perfectly arranged one, at a certain stage often ceases to be enough for people who train. That is when it comes time to add some supplements for athletes to it.
By practising any sport discipline on a regular basis, e.g. bodybuilding, you automatically increase your body’s demand for particular substances you need to live. The demand of active people is sometimes so high that it is simply impossible to meet it with “normal” and “ordinary” food. If you wanted to do so, you would have to spend a lot of time on detailed study of the composition and nutritional values of individual food products, and then compose a diet from them, as well as prepare the meals themselves. So supplements are products that absolutely make life easier. They partially replace ordinary food. They supplement your diet with compounds that are good for you, which you may need a bit more of now than you used to, when you weren’t such a keen sportsman yet.
In general, nutritional supplements for athletes do not only contain vitamins and minerals. They are supplemented with various other substances with special biological effects, which cannot be found in ordinary food or are present in too small a dose to be of any use to the body. Preparations of this type can be used by both professionals and amateurs. So your length of experience at the gym does not matter much. If you only feel that such additional support could be useful to you, just use it.