I have been supplementing exclusively with beta alanine preworkout for a few weeks now. I found that what I was mainly looking for in a pre was endurance, not necessarily a pump to stroke my ego or enough caffeine to give me a headache. Usual pre's were either ineffective at a particular dose, or could stimulate me into having a headache and ruining my heavy sets. Beta-alanine is the component of pre's that give you that tingling sensation (a reason to mix your own so you actually know what each ingredient does - that tingling does NOT mean you are getting a lot of energy), but it reduces muscle fatigue and gives me great endurance. I will continue to supplement with this instead of a ready made preworkout.
A few months ago I saw that my C4 stash was running a bit low, and wanted to try my hand at my own preworkout. Ordered the following from BPN: Optimum Nutrition Creatine Powder 2000 grams, Now Foods Beta Alanine Powder 500 Grams, Primaforce Citrulline Malate 200 Grams. Already had 200mg Caffeine tablets laying around. Beta Alanine has been proven to promote muscular endurance, but it is responsible for giving that ���tingly' feeling. I finally tried this combo a week ago, mixing 5g Creatine, 3g Beta Alanine, and about 6g Citrulline with 200mg of Caffeine, and hit the gym. Wow! I have not had a response like that since the first time I tried Jack3d all of those years ago! PR and enough arrogance to attempt to add another 22lbs to the bar! Highly recommended IF you have your own set of scales to measure out the ingredients, and highly recommend BPN from all the great service I've had!