Low-fat diet based on carbohydrates is the number 1 enemy of testosterone. Stop eating refined processed sugars and carbs. Your body needs fat and cholesterol to make testosterone. Forget about drugs and pills, what you need is to start eating lot's of animal products such as eggs, cheese, full fat milk, yogurt, various types of meat, fish and lot's of fruits and veggies.

Another way to boost your testosterone is do very high intensity weight training. Lifting heavy weights for low reps. Compound excercises with free-weights are much better then machines. Do a search and I am sure you will find some answers. Personally I don't have that problem but a lot of men do. In fact most modern men today have 30% lower testosterone then their forefathers 50-60 years ago, I blame our modern diet and lack of physical intensity and our soft easy way of living.