Here is some information about caffeine:
Caffeine FAQ | Coffee and Caffeine FAQ
Taken from the website:
Regular caffeine consumption reduces sensitivity to caffeine. When caffeine intake is reduced, the body becomes oversensitive to adenosine. In response to this oversensitiveness, blood pressure drops dramatically, causing an excess of blood in the head (though not necessarily on the brain), leading to a headache.
This headache, well known among coffee drinkers, usually lasts from one to five days, and can be alleviated with analgesics such as aspirin. It is also alleviated with caffeine intake (in fact several analgesics contain caffeine dosages).
Often, people who are reducing caffeine intake report being irritable, unable to work, nervous, restless, and feeling sleepy, as well as having a headache. In extreme cases, nausea and vomiting has also been reported.
References.
Caffeine and Health. J. E. James, Academic Press, 1991. Progress in Clinical and Biological Research Volume 158. G. A. Spiller, Ed. Alan R. Liss Inc, 1984.
Here is NO-xplode's ingredients label. What they have is a "propriety blend" meaning you the consumer don't know EXACTLY what amounts of each ingredients you are taking in.
N.O. X-plode's Propriety Blend:, Efforsorb (delivery system), N.O. Meta-Fusion : (patent pending), L Arginine AKG, L Citrulline Malate, L Citrulline AKG, L-Histidine AKG, RC-NOS, Rutaecapine (95%), Gynostemma Pentaphyllum (Gypenosides 95%), NAD (nicotinamide adenine dinucleotide), Muscle Volumizing Creatine Matrix (patent pending), CEM3 (creatine ethyl ester malate), Dicreatine Malate, Trimethylglycine, Glycocyamine, Guanidino Propionic Acid, Cinnulin PF (aqueous cinnamon extract), Ketoisocaproate Potassium, Ener-Tropic Xplosion:, L Tyrosine, L-Tyrosine AKG, Taurine, Glucuronolactone,
Methylxanthine (caffeine), MCT's (medium chain triglycerides), Vinpocetine (99%), Vincamide (99%), Vinburnine (99%), Phospho-Electrolyte Replacements:, DiCalcium Phosphate, Dipotassium Phosphate, Disodium Phosphate, Glycerol Hydrating Polymers:, Potassium Glycerophosphate, Magnesium Glycerophosphate, Glycerol Stearate, Maltodextrin, Natural & Artificial Flavors, Citric Acid, Sodium Bicarbonate, Sucralose (spenda), Acesulfame K, Potassium Citrate, FD&C Yellow 5 Lake, FD&C Yellow 6 Lake, Calcium Silicate