Nitrous Malate (TM) Diarginine Malate is a compound that combines two L-arginine molecules with malic acid. It is used in athletic and exercise supplements primarily for its purported ability to enhance nitric oxide (NO) production, which can theoretically improve blood flow, nutrient delivery, and exercise performance. There is scientific rationale for the use of L-arginine in sports nutrition, as arginine is a precursor to nitric oxide synthesis. Increased NO production may promote vasodilation and potentially enhance endurance or reduce fatigue during exercise.

However, the scientific evidence supporting the efficacy of L-arginine supplementation for improving athletic performance is mixed. Several studies have shown that oral L-arginine supplementation has minimal or no significant impact on NO production, blood flow, or exercise performance in healthy individuals. This is partly because oral arginine is rapidly metabolized in the gut and liver, limiting the amount that reaches the bloodstream. The addition of malate is theorized to support energy production via the Krebs cycle, but robust evidence to support a synergistic benefit of the malate form over other forms of arginine is lacking.

In summary, while there is a scientific basis for the use of arginine-based supplements in exercise aids, and some studies suggest a modest benefit in specific populations (e.g., older adults or those with cardiovascular issues), the overall evidence for significant performance enhancement in healthy, trained athletes is weak. The rating reflects the presence of scientific rationale but limited clinical efficacy.