Updated: Jul 10, 2020
What is L-arginine?
L-arginine is an amino acid. Amino acids are the building blocks of proteins and divided into essential and nonessential categories. Nonessential amino acids are made in the body, but essential amino acids are not. As such, they must be provided through dietary intake.
L-arginine is considered semi-essential or conditionally essential, meaning that it becomes essential under certain circumstances and conditions, including pregnancy, infancy, critical illness, and trauma. It’s necessary for the production of nitric oxide, a signaling molecule that’s needed for a variety of bodily processes and functions, including blood flow regulation, mitochondrial function, and cellular communication.
Additionally, it acts as a precursor to other amino acids, including glutamate, proline, and creatine, and is essential for the health and functioning of your immune system. Arginine is necessary for the development of T-cells, which are white blood cells that play central roles in immune response.Because L-arginine has so many critical roles in your body, a deficiency in this amino acid can disrupt cellular and organ function and lead to serious adverse health outcomes .
L-arginine is produced in several ways. It can be synthesized from the amino acid citrulline through the breakdown of body proteins, or it can be obtained through dietary protein intake. It’s concentrated in certain protein-rich foods, including meat, poultry, dairy, nuts, soy products, and fish. The average daily intake of L-arginine from foods is reported to be 4–6 grams.
Additionally, L-arginine can be obtained by taking supplements. L-arginine supplements are widely available and can be found in powder, liquid, capsule, and tablet form at grocery stores, supplement stores, and online.
Athletic performance enhancement
Limited evidence suggests that L-arginine supplements may enhance exercise performance by increasing nitric oxide in the body, which improves blood flow and oxygenation to muscles. However, most studies investigating this relationship have found that L-arginine is not beneficial for improving athletic performance.
Dosage and how to take Doses of L-arginine vary widely depending on what it’s being used to treat. For example, studies investigating the effects of L-arginine on blood pressure have used doses of 6–30 grams per day for 2–24 weeks.
In those with erectile dysfunction, research has suggested that supplementing daily with 1.5–5 grams of L-arginine may significantly improve symptoms.
When used to treat preeclampsia, the dose typically ranges from 3–4 grams daily for up to 12 weeks, or until delivery under a doctor’s supervision. L-arginine may also be given intravenously to pregnant women with high blood pressure in the clinical setting.
Although higher doses are often used in research and clinical settings, it’s recommended that daily dosing of L-arginine be kept under 9 grams per day to avoid potential gastrointestinal side effects, including nausea, diarrhea, and bloating. Like other single amino acids, it’s recommended to take L-arginine between meals for maximum absorption.