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ARGININA

Also known as: L-Arginine, Arginine

Overview

L-Arginine is a naturally occurring, semi-essential amino acid found in dietary proteins and synthesized within the body. It is a precursor to nitric oxide (NO), a crucial molecule for vascular function. As a supplement, L-Arginine is used to enhance athletic performance, improve cardiovascular health by modulating blood pressure and lipid profiles, and support muscle function. It is available in various forms, including free-form powder and capsules, often combined with other supplements. Research on L-Arginine supplementation is extensive, with numerous randomized controlled trials (RCTs), systematic reviews, and meta-analyses providing a robust evidence base. Its bioavailability can be affected by co-ingestion with other amino acids or food. L-Arginine's metabolism involves conversion in the liver and kidneys.

Benefits

L-Arginine supplementation has several evidence-based benefits: * **Athletic Performance:** Improves aerobic capacity (VO2 max) and anaerobic performance by enhancing energy metabolism. A 2020 meta-analysis of RCTs supports these findings. * **Blood Pressure Reduction:** Significantly reduces both systolic and diastolic blood pressure in adults, with a dose-dependent effect, as shown in a 2022 meta-analysis. This suggests cardiovascular benefits, especially for those with hypertension or prehypertension. * **Lipid Profile Improvement:** Reduces blood triglyceride (TAG) levels, according to a 2019 meta-analysis. Evidence for effects on other lipid parameters is inconclusive. * **Strength Training Performance:** Mixed results, with some studies reporting improvements in peak strength and muscle performance, but overall evidence remains controversial.

How it works

L-Arginine works primarily by serving as a substrate for nitric oxide synthase enzymes, which convert it into nitric oxide (NO). NO is a potent vasodilator that relaxes blood vessels, improving blood flow and oxygen delivery to tissues. This mechanism underlies many of L-Arginine’s effects on cardiovascular health and exercise performance. Additionally, L-Arginine may influence energy metabolism pathways and muscle protein synthesis, contributing to its ergogenic effects.

Side effects

L-Arginine supplementation is generally safe at recommended doses in healthy adults. Common side effects include mild gastrointestinal discomfort such as nausea, diarrhea, and bloating. Uncommon side effects include headache, hypotension (due to vasodilation), and rare allergic reactions. Severe hypotension or exacerbation of herpes virus infections are rare. L-Arginine may interact with antihypertensive drugs, nitrates, and phosphodiesterase inhibitors (e.g., sildenafil), potentially causing additive blood pressure lowering effects. Caution is advised for patients with low blood pressure, herpes virus infections, or those on blood pressure medications. Safety in pregnant or breastfeeding women and children is not well established.

Dosage

The minimum effective dose of L-Arginine is around 3 grams per day. Commonly studied doses range from 3 to 9 grams per day, divided into multiple doses. Up to 20 grams per day has been used in clinical settings, but higher doses increase the risk of side effects. For exercise performance, acute supplementation 30-60 minutes before activity is typical. L-Arginine is available as free-form powder, capsules, or combined with other supplements. Bioavailability can be affected by co-ingestion with other amino acids or food. No specific cofactors are required, but adequate overall nutrition supports efficacy.

FAQs

Is L-Arginine effective for improving exercise performance?

Yes, particularly for aerobic capacity and endurance, with moderate evidence supporting increased VO2 max.

Can L-Arginine lower blood pressure?

Yes, meta-analytic evidence supports modest but significant reductions in blood pressure.

Are there risks of taking L-Arginine daily?

Generally safe at recommended doses, but caution is advised for those on blood pressure medications or with certain health conditions.

When should I take L-Arginine for best results?

For exercise, 30-60 minutes before activity; for cardiovascular benefits, consistent daily dosing is used.

Does L-Arginine improve strength training outcomes?

Evidence is mixed and less robust compared to aerobic performance benefits.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/32370176/ – This systematic review and meta-analysis evaluated the effects of L-Arginine on aerobic and anaerobic athletic performance. The study found significant improvements in aerobic capacity (VO2 max) and anaerobic performance linked to enhanced energy metabolism, suggesting that L-Arginine supplementation can be beneficial for athletes.
https://pubmed.ncbi.nlm.nih.gov/34967840/ – This systematic review and dose-response meta-analysis analyzed RCTs on L-Arginine supplementation's effect on blood pressure in adults. The study demonstrated dose-dependent reductions in systolic and diastolic blood pressure, indicating that L-Arginine may have cardiovascular benefits for individuals with hypertension or prehypertension.
https://physoc.onlinelibrary.wiley.com/doi/full/10.14814/phy2.14739 – This systematic review and meta-analysis investigated L-Arginine’s effect on lipid profiles. The study found a significant reduction in triglycerides but insufficient evidence for effects on other lipid parameters, suggesting that L-Arginine may help improve certain aspects of lipid metabolism.
https://f1000research.com/articles/10-1072 – This systematic review and meta-analysis assessed the effects of acute L-Arginine supplementation on strength training performance. The results were mixed, with some improvements in peak strength but overall inconclusive, indicating that the benefits of L-Arginine for strength training are not consistently supported by evidence.
https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/effect-of-larginine-supplementation-on-lipid-profile-a-systematic-review-and-metaanalysis-of-randomised-controlled-trials/F9FE43B86AD15C869CA4364F45978CC2 – This systematic review and meta-analysis examined the effect of L-arginine supplementation on lipid profiles. The study found that L-arginine supplementation significantly reduces blood triglyceride (TAG) levels, suggesting a potential benefit for improving lipid profiles, although evidence for other lipid parameters remains insufficient.