NO-precursors: Arginine AKG, Citrulline Malate and L-Ornithine

As NO widens the blood vessels and makes them more flexible, it increases the amount of blood that the heart can pump - and thus the amount of oxygen and nutrients transported to the muscles. This extra source of oxygen and nutriment is important in order to build up the energy needed for your training and to not get tired so quickly.
Improving your blood flow also helps to improve your muscle pump. And even though the pump in itself is a short-term phenomenon, it is nonetheless important for muscle growth. This “strain” on the muscle membranes activates processes which support protein synthesis.
A higher blood flow also improves the circulation of testosterone and growth hormones, which can boost your power during the training.
Arginine AKG is the most widely (and often the only) used ingredient in NO-boosters and pre-workout supplements.
A lot of research has already been conducted on arginine, and the latest findings have confirmed yet again that a supplementation with arginine has anabolic effects on the muscles during power training. (1) Brazilian researchers concluded that power athletes obtained more results from their training by starting to use 3g of L-arginine per day. (2) This study is particularly interesting, because most people think that you have to use 6g in order to get good results.
However, it is very useful to combine arginine AKG with citrulline malate.
They are both NO-precursors, but use different mechanisms to penetrate into the cell: Citrulline is gradually converted into arginine instead of being broken down in the liver. 
Spanish sport scientists of the university of Cordoba have reported that power athletes get better results using citrulline malate. (3) Volunteers who used citrulline malate before their workout were able to do more reps than those who took a placebo. The more sets they did, the bigger the difference became. A number of scientists even state that L-citrulline is one of the best NO-precursors. (4)
L-ornithine is a non-essential amino acid (synthesized out of other amino acids and nutrients) that plays a key role in the metabolism of amino acids. L-ornithine is a precursor of L-arginine and of citrulline and has a similar effect. L-ornithine is not an NO precursors in itself, but it is converted into L-arginine. This conversion takes some time, so by combining L-ornithine with L-arginine you can extend its effect. This is why these 2 amino acids are often combined.
In addition, L-ornithine improves stamina and decreases fatigue during prolonged efforts. (5)
An extra amount of L-ornithine accelerates the removal of ammoniac and other waste materials and decreases fatigue during your workout.
It is advisable to use a mixture of different NO-precursors, as it will certainly have greater effect.  
Arginine AKG and Citruline Malate are used as key ingredients in SynTsize Pump and SynOxy Boost.
Arginine AKG, Citruline Malate and L-Ornithine are used as key ingredients in SynNOvator Beta+ andin SynNOvator Crea+.
SynTsize Pump SynTech no-precursorenSynOxy SynTechSynnovator SynTech No-PrecursorenSynnovator Crea SynTech


1) J Strength Cond Res. 2010 Mar 17
2) Rev Bras Med Esporte. 2007 Mar/Apr (13)2:112e-115e
3) J Strength Cond Res. 2010 May;24(5):1215-22
4) Nutrition. 2007 Mar;23(3):261-6
5) Nutr Res. 2008 Nov;28(11):738-43