Supplements are required for growth if you naturally don't get them. Any external chemical you take will have certain amount of side effect. You can do the cost benefit test and find if it's really worth taking this for several marks. Also not all of these medicines have equal results on every person. Even if some of them are clinically tested but they don't guarantee results.
Next Steps
Use study techniques that can be useful.
Health Tips
Also now the world looks more for skill than just marks.