L-Citrulline Supplement Spotlight

Resistance training has several mechanisms of causing muscular hypertrophy.

One vital mechanism is facilitated by the working muscle being engorged in blood, swelling in size, stretching the fascia, delivering nutrients and transporting away toxins. Known around the gym floor simply as the ‘pump’, the true importance of this increase in blood flow in the working muscle is often understated.

The pump is indeed pivotal in obtaining maximum hypertrophy by fatiguing the muscle, creating localised inflammation, stretching the fascia and causing an exaggerated healing response in the form of new tissue growth.

So how does the pump occur and where does L-Citrulline come in to this picture?

Well you see, it’s all about Nitrogen!

A quick glance at your favourite pre-workout label will highlight the importance of Nitric Oxide (NO2) production for vasodilatation.

NO2 drives increased blood flow to working musculature, enhancing nutrient delivery, stretching of the Fascia, transport of metabolic waste and by products from exercise, as well as assisting in energy production.

Now NO2 production and regulation is driven by elevated blood serum levels of Arginine, an amino acid that brings Citrulline to centre stage!

You see, supplementing with oral Arginine has been common practise for years in the Bodybuilding world in an attempt to increase blood Arginine levels and thus NO2 levels. 

The problem is that supplementing with straight Arginine is actually a pretty mediocre way to increase blood Arginine levels! This is purely because ingestion of oral Arginine must pass the stomach, then Liver and Kidneys to be liberated into the blood stream and cause those pumps we are all chasing for growth! Yet, the vast majority of Arginine is either absorbed locally in the smooth muscles of the stomach wall, causing localised vasodialation but not systemic, or actually broken down through via the Kidneys. So if the stomach doesn’t get it, the Kidneys will! This equation obviously leaves very little bioavailable Arginine to enter the blood stream, increase Nitric Oxide levels and thus potentiate a muscle pump.

This is where L-Citrulline comes in!

Citrulline is funnily enough, the most potent amino acid at increasing blood serum levels of Arginine of all other commonly known amino acids. This is because unlike Arginine, which enters your Stomach in its active form and is thus largely metabolised by organs before it reaches the blood, Citrulline doesn’t actually convert to Arginine until it passes through the Kidneys. It survives the journey through the stomach and is converted after first pass through the filtering organs into Arginine.

The beauty here is that it doesn’t convert to Arginine until it is already in the blood stream, directly increasing production of NO2 and thus inducing the filthy pump we all know and love! So if you want higher blood levels of Arginine, supplementing with Arginine isn’t actually the smartest move!

Take Home:

Take L-Citrulline 30-45 minutes before your next workout at a dosage of 6 to 8 grams.

There are several forms, such as Citrulline Malate most commonly, which has the added benefit of feeding the Kreb cycle with the Malic acid attached to it. This will of course aid in energy production and combined with the L-Citrulline bound to it, will create a powerful boost in Nitric Oxide levels during your training session.

So next time you are looking for a great pump product, perhaps start looking less for the Arginine and more for the Citrulline, your muscles will thank you for making the switch!