L-arginine vs. L-citrulline Benefits, Reviews and Dosages

What are the differences between L-arginine vs. L-citrulline?

Both supplements are combined in muscle building formulas to support protein metabolism and maintain muscle tissue.

Both supplements are non-essential amino acids, however there is evidence that less L-citrulline is needed by the body. As much as 80 percent of the supplement is converted to L-arginine in the blood vessels.

Both of these supplements are used to increase nitric oxide (NO) levels in the blood, promoting positive effects for muscle growth, energy, stamina and strength in bodybuilders.

The question is whether L-arginine or L-citrulline is more effective at improving performance and supporting muscle development.

L-Arginine

Amino Acid

Pre-Workout

Muscle Growth

Sexual Health

How It Works:

• Boosts nitric oxide production for workouts
• Reduces fatigue & promotes muscle growth
• Supports immune function & sexual health

Dosage:

Between 3 - 6 g per day

Safety:

Rated Possibly Safe

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L-arginine Overview

L-Arginine is an amino acid that gets converted into Nitric Oxide in the blood stream.

It is used by bodybuilders, for the treatment of certain cardiovascular conditions and as a libido enhancer and to improve male sexual function.

L-Arginine foods can be sourced from dairy products, beef, pork, gelatine, poultry, wild game and seafood.

Wheat germ and flour, lupins, buckwheat, granola, oatmeal, peanuts, nuts, seeds, chickpeas and cooked soybeans are also sources.

L-Arginine benefits include the ability to help the body produce and synthesize proteins. Proteins are essential in the process of muscular repair and growth. It is also a component in the formation of bones and tendons.

It helps stimulates the production of growth hormones, natural sterols, which help the muscles rebuild and enlarge after an intense workout. L-Arginine improves immune function and reduces the healing time of injuries.

A study published in the Journal of International Society of Sports Nutrition in March 2010 on older professional cyclists showed that those supplementing with L-arginine and a pre-treatment of Vitamin C and E had a significant increase in NO production during exercise.

This supplement also helps remove cortisol, which controls stress levels, and other waste products in the body. A study in the Journal of the American College of Cardiology found this supplement improved vascular function for people with Angina.

L-citrulline Overview

L-citrulline comes from the Latin word citrullus, meaning watermelon. To increase the supply of L-citrulline from food you can eat more watermelon, cucumber, garlic, onions, and the milk protein, casein.

L-citrulline is used for fatigue, muscle weakness, sickle cell disease, erectile dysfunction, high blood pressure, and diabetes. It is also used for heart disease, body building, increasing energy, and for improving athletic performance.

Without L-citrulline, people experience mental and physical fatigue and have chronic low energy levels. The recommend dosage for L-citrulline supplements is one and one-fourth teaspoons (three grams) twice a day.

L-citrulline benefits include its ability to help reduce body fat levels. It is also helpful in maintaining natural energy production. ATP (adenosine triphosphate) energy can often drop off drastically during a hard workout.

ATP serves to store energy in muscles which is released when it is hydrolyzed (protein broken down into its component amino acids) to produce ADP. ADP is produced during muscle contraction. It is reformed when the muscle relaxes.

L-citrulline also acts as a vasodilator. This helps to open and expand blood vessels. This is the reason for the reduction in blood pressure levels. For weight and strength training athletes, this supplement helps in the release of nitric acid.

NO helps build proteins and re-form muscles that have been torn down from intense training. L-citrulline acts in the urea cycle to remove lactic acid from the body which is produced as working muscles become tired.

The Journal of Strength & Conditioning Research May 2010 study showed Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. Athletes that undergo intensive preparation involving a high level of training or in competitive events might profit from CM.

In pre-workout products the most effective products provide at least 6 grams of citrulline malate at a 2:1 ratio of L-citrulline to malate (provides 4 grams of L-citrulline). With this workout formula combination there is enough L-citrulline for the exertion of pumping iron and greater energy.

L-Arginine vs. L-Citrulline

The question among bodybuilders is whether L-arginine or L-citrulline is better for increasing nitric oxide levels.

German researchers found that a 3 grams dose of L-citrulline produced the highest increase in L-arginine and NO (nitric oxide) levels.

This is because the process of breaking down L-citrulline by-passes the liver. If you take L-arginine directly, the amino acid is processed and broken down in the liver by the enzyme arginase.

L-Arginine is first oxidized into N-hydroxyl-arginine, which is then further oxidized to L-citrulline along with release of nitric oxide. L-citrulline facilitates the production of L-Arginine.

Both L-Arginine and L-citrulline are nitric-oxide boosting substances. Both supplements aid in the elimination of oxidative stress on the arteries and ease clogging or congestion.

However, research suggests that L-citrulline may be more effective at a lower dosage. That being said, many companies will see a stack with both of these ingredients so you can obtain the benefits of both.

L-arginine and L-citrulline Side Effects

L-arginine and L-citrulline should not be taken with blood pressure medication or with a low blood pressure condition. These supplements should also not be taken with Nitrates medications, insulin and cholesterol-lowering agents.

Sildenafil (Viagra) may also interact with these supplement. These supplements should be avoided for people with kidney and or liver impairments.

These supplements may make herpes virus conditions and Asthma symptoms worse.

They should also be avoided by people with a Guanidinoacetate methyltransferase deficiency. L-arginine is not recommended in patients following an acute heart attack.

Use L-arginine and L-citrulline stack products with caution if pregnant or breastfeeding.

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