Some people just have shitty genetics bro, hate to say that, but I also include myself in that group.
Next, it really depends on what you mean by "drugs." Are you talking about AAS, ph's, otc fat burners, clen, etc. We need to know what you mean by that term.
Third, it is possible to get very low bodyfat without "drugs" but you have to have a good, check that, great diet, do plenty of cardio, and weight train.
Also, have you been giving the diet and exercise programs time to really work, or have you just been hitting the "miracle" programs that are supposed to make you arnold in a month? Changes take time and lots of it.