Citrulline is a non-essential (your body produces it) amino acid that your body converts into L-arginine. It plays a key role in creating the "pump" effect by supporting nitric oxide production and improving blood flow. Citrulline may also reduce fatigue and post-workout muscle soreness. You'll see this one on most labels as L-citrulline or citrulline malate.
L-arginine is another amino acid that plays a role in nitric oxide production. Your body converts L-arginine into nitric oxide, which improves circulation by expanding your blood vessels.
Creatine is one of the most researched supplements and is well-known for its role in building muscle. It helps your muscles produce more ATP (adenosine triphosphate), a powerful energy source that's used for muscle contraction. Most creatine supplements feature creatine monohydrate, but some use creatine HCl instead. Creatine can be used to improve workout performance, post-workout recovery, and more.
This non-essential amino acid increases carnosine levels in your muscles, which in turn helps your body deal with lactic acid build-up. The means more endurance and greater resistance to fatigue. Beta alanine also plays a key role in power output.
Agmatine is a product of L-arginine that plays a role in nitric oxide regulation. It can also be used to reduce neuropathic pain.
This powerful stimulant likely needs no introduction. You probably drink it daily in the form of coffee or tea and already know that it supports energy and focus, two key goals of a good pre-workout supplement.
Stimulant vs Non-Stimulant
Stimulants, like caffeine, stimulate the nervous system, providing increased energy and focus. For the stim-sensitive, they may also come with uncomfortable side effects like jitters and tingling. Non-stimulants, including beta alanine and creatine, don't affect the nervous system .Most pre-workout supplements contain stimulants, but if you're willing to ditch the energy and focus benefits, there are some non-stimulant options available.