Understanding Amino Acids and Why We Use L-Citrulline and L-Arginine

Benjamin Payson
7 days ago
3 min read

What Are Amino Acids

Amino acids are the fundamental building blocks of proteins and play essential roles throughout the body. They combine to form proteins that support nearly every biological process, from muscle repair to energy production¹. Chemically, each amino acid contains a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a unique side chain that defines its specific function².

There are about 20 amino acids commonly used in human proteins³. They are categorized as essential (must come from diet), nonessential (made by the body), and conditionally essential (normally produced, but may be needed from diet under stress or illness)¹.

Beyond forming proteins, amino acids act as precursors to important molecules, play a role in energy metabolism, and help repair tissue⁴. In short, amino acids are the body’s raw materials for performance, recovery, and adaptation, all critical during physical activity and heat stress.

How L-Arginine and L-Citrulline Are Derived

L-Arginine

L-arginine is an amino acid naturally present in many protein rich foods such as poultry, fish, red meat, soy, and dairy⁵. The body can also synthesize arginine under normal conditions. In supplement form, it is typically produced through controlled fermentation or extraction and standardized to ensure the biologically active L configuration⁶. The L-arginine used in Heat Hydration is certified Vegan.

L-Citrulline

L-citrulline is found naturally in watermelon and is not one of the 20 amino acids used in proteins. Inside the body, citrulline is converted into arginine through processes in the kidneys⁷. This makes citrulline an indirect but effective way to raise arginine levels and promote the same benefits associated with arginine supplementation.

In formulation, citrulline acts as a “precursor” - it supports the body’s ability to sustain arginine levels and, in turn, nitric oxide production⁸.

What L Arginine and L Citrulline Do in the Body

The Nitric Oxide and Vasodilation Pathway

Both L-arginine and L-citrulline play a critical role in producing nitric oxide (NO), a compound that relaxes and widens blood vessels, improving circulation⁹. Arginine directly fuels the enzyme nitric oxide synthase, which generates NO in endothelial cells lining the blood vessels¹⁰. Citrulline works upstream by converting to arginine, thereby sustaining higher arginine levels and maintaining nitric oxide production¹¹.

Why This Matters for Heat Hydration

When you exercise or spend time in high temperatures, your body must efficiently transfer heat from the core and working muscles to the skin, where it can dissipate. Improved circulation through vasodilation enhances this process. Increased blood flow helps deliver oxygen and nutrients to muscles while carrying away heat and metabolic waste.

By including L-citrulline and L-arginine in Heat Hydration, we aim to support your body’s natural cooling system. Improving blood flow so that heat can be more effectively extracted from muscles and the core. This physiological support complements the electrolyte balance provided by the rest of our formula.

The Benefits of L Citrulline and L Arginine

1. Improved Circulation and Blood Flow - Both amino acids enhance nitric oxide production, which increases vessel diameter and blood flow⁵ ⁹. This can support oxygen delivery, nutrient transport, and temperature regulation.

2. Enhanced Heat Extraction and Thermal Regulation - Greater blood flow helps move heat away from deep muscle tissue toward the skin for dissipation. While direct research on heat extraction is limited, studies show that these amino acids improve vascular responsiveness and oxygen delivery¹².

3. Better Performance and Reduced Fatigue - By supporting circulation and nutrient delivery, these amino acids may help delay fatigue and improve endurance under stress. Research suggests citrulline supplementation can enhance blood flow and exercise tolerance¹³.

4. Faster Recovery and Vascular Health - Both amino acids have been linked to improved endothelial function, which supports cardiovascular health and recovery following physical exertion or heat exposure¹⁴.

Conclusion

Amino acids are more than just muscle builders, they are integral to circulation, recovery, and thermoregulation. L-citrulline and L-arginine support nitric oxide production, improving blood flow and assisting your body’s ability to extract and release heat.

By incorporating these amino acids, Heat Hydration offers more than hydration. It provides physiological support to help you perform, recover, and stay cool when the heat is on.