RE: tribulus testeris and anabolic activators and substances
The biggest side effect is going to be to your wallet. Spend your money on quality food instead. Over-the-counter supplements that promise elevated testosterone levels and miracle rates of growth are bullsh!t. If you're just starting out you can look forward to at least a couple of years of impressive growth by following a decent diet, training and rest regime. Check out the diets in the diet diet section/articles for guidance. Besides food, the only chemicals that are anabolic activators are those that you as a beginner are not yet ready for or are even requiring.
Tribulus is best used by men in their mid-thirties and above who's natural testosterone levels are dropping or sometimes in PCT following an AAS cycle.
Don't bother shelling out for these bottles advertised in mags like Flex which are endorsed by pro bodybuilders which are hailed as 'a breakthrough in bodybuilding' etc. They are just designed to relieve you of your hard-earned. It took me a couple of years to realise this. Take my advice and stay away. If you want to spend money on supps then first use whey, dextrose, creatine, caffeine and multivits since they are much more likely to have a beneficial effect.