Best Supplement Ingredients For Pump
Muscle pumps not only have an aesthetic appeal but also physiological benefits. Contracted muscles engorged with blood signifies the delivery of critical nutrients to the muscles. These nutrients facilitate increases in muscular size, strength, and endurance.
Increased vascularity occurs as a result of vasodilation, the expansion of blood vessels, and increased blood flow to muscles as a result of contracting the target muscles. You can further enhance vascularity by decreasing your body fat to reveal veins as well as muscles you've spent so much effort and time building.
This article examines a number of popular clinically-proven and emerging novel compounds designed to increase pumps and vascularity.
#1 - Agmatine Sulfate
Agmatine sulfate is one of the most popular ingredients used in pre and some intra-workout formulas because it's downright effective in increasing pumps and vascularity. This heavy-hitting compound is derived from the amino acid L-arginine, a once popular ingredient in pre-workouts.
This compound regulates nitric oxide synthase to increase blood flow to the muscles and enhances cognitive focus.  In addition to providing mind-blowing muscle pumps agmatine sulfate also appears to have nutrient partitioning, pain relief, and neuroprotective benefits. 
There is currently no clinically recommended dose of agmatine sulfate but most pre- and intra-workout products contain between 500mg and 1,500mg per serving.
You should not consume agmatine sulfate alongside dietary protein sources as it competes with (and loses to) Arginine since they both use the same chemical transporter within the body. When consumed on an empty stomach, with branched chain amino acids (BCAAs), or alongside only fat and carbohydrates, agmatine sulfate provides increased muscle definition intra- and post-workout.
#2 - Citrulline (L-Citrulline & Citrulline Malate)
L-Citrulline and citrulline malate are the two most commonly used forms of citrulline in pre- and intra-workout products. L-citrulline is an amino acid clinically proven to significantly decrease fatigue and muscle soreness while increasing nitric oxide, flow, and arginine in the blood.  Citrulline not only improves pumps and vascularity but also staves off intra-workout fatigue and facilitates post-workout recovery, making it a must-have in your supplement stack.
L-Citrulline is a free-form amino acid. Citrulline malate is bound to the molecule malic acid, typically in a 2:1 ratio. Malic acid is a natural substance found in fruits and involved in the creation of cellular energy.
Those looking to improve general blood flow should consume 1,000mg of citrulline malate three times per day while those looking to perform at their peak on the field or in the gym should consume 6,000 to 8,000mg of citrulline malate approximately 60 minutes prior to exercise. 
#3 - Nitrosigine®
Nitrosigine®, also known as arginine inositol silicate, is a breakthrough supplement produced by Glanbia Nutritionals scientifically proven to increase nitric oxide and silicon blood levels pre-, intra-, and post-workout.
A daily oral dose of 750mg to 1,500mg of Nitrosigine® pre-workout increases vasodilation, arginine blood levels, maximum blood flow, and strengthen arterial walls as well. 
#4 - HydroMax Glycerol
HydroMax Glycerol s another strong ingredient being used to replace glycerol monostearate (GMS). Comprised of 65% glycerol and 35% silica by weight, this compound offers the most concentrated and pure powder glycerol on the market and mixes easier than GMS. Consuming a minimum of one gram per kilogram of body weight prior to your workout will prevent dehydration via decreased urine volume, improve exercise performance by prolonging endurance, and significantly increase muscular pumps. 
While most of us won't be consuming such a large quantity of this compound, just 700mg to 2,000mg can increase plasma and intramuscular volume, leaving you with enhanced pumps and vascularity intra- and post-workout. 
#5 - Betaine (Nitrate & Anhydrous)
Betaine, also known as trimethylglycine, is a compound naturally made by the body but commonly found nitrate or anhydrous forms in pre- and intra-workout supplements. Betaine plays crucial roles in liver function, carnitine production, cellular reproduction, and preventing the buildup of amino acid homocysteine in the body.  High homocysteine levels increase the likelihood of developing hardened arteries, which decreases blood flow to muscles and critical organs. 
Oral daily doses of 500mg to 3,000mg can increase anaerobic running capacity, improve muscular endurance, and improve blood flow.
#6 - Beet Root (Beta Vulgaris)
Beets are a plant with leafy green leaves and either white, gold or deep purple stems and roots. The bulbous root is the most commonly consumed portion of the beet and is often an acquired taste. Beetroot is rich in nitrates which promote whole-body blood flow and many slow or reverse the stiffening of arteries.  In addition to being high in nitrates beetroot contain high levels of folic acid, fiber, manganese, and potassium. 
While many of these nutrients are stripped during the processing of beetroot for supplements, the ingredient can still enhance exercise performance and endurance.
Other Pump-Inducing Compounds
L-Norvaline. L-Norvaline is an unbranched form of the essential branched-chain amino acid (BCAA) L-valine. Norvaline increases the body's natural upper limit of nitric oxide production by up to 55%, which as a result increases nutrient transport to the blood, muscular pumps, and vascularity. 
Compared to the L-Valine content of many pre- and intra-workout supplements, the L-Norvaline content is much lower. A large quantity is not required for the body to harness nitric oxide synthase-inducing effects.
Glycerol monostearate (GMS). Glycerol monostearate (GMS) is an odorless white powder derived from stearic acid previously used to increased muscle pumps but has since been replaced by HydroMax glycerol. The active ingredient in both compounds is glycerol, a sugar alcohol derived from animal fats and oils used to add body to food products. 
Glycerol hydrates and increases muscle pumps by drawing water and fluid into the blood cells. 
Rutacaerpine. Rutacaerpine is an alkaloid isolated from the Evodia Rutaecarpa plant and is commonly used in Chinese herbal medicine.  100mg of Rutacaerpine one to two times daily appears to relax and dilate the blood vessels as well as expedite the elimination of caffeine from the body without significant side effects. 
This anti-inflammatory alkaloid is only found in a handful of supplements as part of proprietary blends.
Glutamine Nitrate. Glutamine nitrate offers increased vasodilation benefits from nitrates as well as immunoprotective and recovery-enhancing benefits from the amino acid L-glutamine. Nitrates relax blood vessels and lower blood pressure.
*Be careful not to overconsume nitrates as your body pressure may drop too low and you risk becoming lightheaded or fainting.
Epimedium. Epimedium, also known as Horny Goat Weed, is an herb used in traditional Chinese medicine that not only promotes nitric oxide synthase (NOS) but also increases testosterone and sex drive.  Increased nitric oxide synthase equates to exceptional muscle pumps and ample nutrient delivery to the muscles.
Pomegranate extract. If you love pomegranate seeds or juice, then consider a product with pomegranate extract. Pomegranates have potent antiviral, antibacterial, and antioxidant properties. A handful of human studies suggest that pomegranates increase whole-body blood flow and prevent the thickening and stiffening of arteries.  However, pomegranates may interact with certain medications much like grapefruits so check with your health care professional before using a pomegranate extract regularly.
Pycnogenol. Pycnogenol, also known as pine bark extract, contains high amounts of procyanidins which increases nitric oxide synthase, dilates blood vessels, and offers potent antioxidant properties when dosed daily in an amount between 40mg and 200mg. 
Pycnogenol is also being used in human studies as a compound to treat erectile dysfunction in males.
You can find pycnogenol as a standalone supplement in quantities ranging from 30mg to 100mg.
Resveratrol. Resveratrol, a heart-healthy polyphenol found in the red grape skins and wine, naturally relaxes the blood vessels, improves circulation, and increases vascularity when used at oral doses of 5 to 25mg of trans-resveratrol.  While I do not recommend throwing back a few glasses of wine before a weightlifting session, some professional bodybuilders and physique competitors claim that consuming a glass of red wine before stepping on-stage increases vascularity and the appearance of dry, grainy muscles.
Resveratrol can be taken daily for its beneficial effects on inflammation, blood pressure, insulin sensitivity, and blood flow, specifically to the brain. 
References1) Shaw, Steve. "Ultimate Guide to Agmatine: Benefits, Side Effects & Dosages." Tiger Fitness. N.p., 2016. Web. May 2016.
2) Frank, Kurtis, et al. "Agmatine - Scientific Review on Usage, Dosage, Side Effects." Examine.com. N.p., 2016. Web. May 2016.
3) Frank, Kurtis, et al. "Citrulline - Scientific Review on Usage, Dosage, Side Effects." Examine.com. N.p., 2016. Web. May 2016.
4) Ludlow, Nicholas. "Nitrosigine: The Ultimate Pre-Workout Muscle Pump Ingredient" Tiger Fitness. N.p., 2016. Web. May 2016.
5) Ludlow, Nicholas. "Glycerol Supplements for Workout Energy and Performance." Tiger Fitness. N.p., 2016. Web. May 2016.
6) Bartos, Jeremy. HydroMax Glycerol Powder 65%. Glanbia Nutritionals. N.p., Aug. 2014.
7) Ehrlich, Steven D. "Betaine." University of Maryland Medical Center. N.p., 6 July 2014. Web. May 2016.
8) Frank, Kurtis. "Trimethylglycine - Scientific Review on Usage, Dosage, Side Effects." Examine.com. N.p., 2016. Web. May 2016.
9) "Can beetroot juice give you wings?" National Health Service (NHS) Choices. Gov.UK, 26 Aug. 2015. Web. May 2016.
10) Fisher, Roxanne. "The Health Benefits Of... Beetroot." BBC Good Food. BBC Worldwide Ltd., n.d. Web. May 2016.
11) Vallejo, Rick. "L-Norvaline." Evolutionary.org. N.p., 2016. Web. May 2016.
12) "Glycerol." Dictionary.com. N.p., 2016. Web. May 2016.
13) Wingo, Jonathan E. et al. Influence of a Pre-Exercise Glycerol Hydration Beverage on Performance and Physiologic Function During Mountain-Bike Races in the Heat. Journal of Athletic Training 39.2 (2004): 169175. Print.
14) Dharmananda, Subhuti. "Evodia: Traditional and Modern Uses." Institute for Traditional Medicine. N.p., July 2010. Web. May 2016.
15) "Rutaecarpine (from Evodia Rutaecarpa)." Powder City. N.p., 2016. Web. May 2016.
16) Frank, Kurtis, and Sol Orwell. "Horny Goat Weed - Scientific Review on Usage, Dosage, Side Effects." Examine.com. N.p., 2016. Web. May 2016.
17) Ehrlich, Steven D. "Pomegranate." University of Maryland Medical Center. N.p., 2 Feb. 2016. Web. May 2016.
18) Frank, Kurtis, et al. "Circulation." Examine.com. N.p., 2016. Web. May 2016.
19) Higdon, Jane, et al. "Resveratrol." Micronutrient Information Center. Linus Pauling Institute, 11 June 2015. Web. 12 May 2016.