Citrafuze
Also known as: Citrulline, L-Citrulline
Overview
L-Citrulline is a non-essential amino acid naturally found in foods like watermelon. It plays a crucial role in the urea cycle, a metabolic pathway that removes ammonia from the body, and is a key precursor to nitric oxide (NO) production. Nitric oxide is a potent vasodilator, meaning it helps relax and widen blood vessels, thereby improving blood flow. Due to its role in NO synthesis, citrulline is commonly used as a dietary supplement to enhance exercise performance, particularly high-intensity activities, and to support cardiovascular health. Research on citrulline's efficacy is moderate, with several studies supporting its benefits for exercise performance, though the quality of evidence varies, including high-quality systematic reviews and meta-analyses. It is generally well-absorbed and considered safe for consumption.
Benefits
Citrulline primarily offers benefits for exercise performance, particularly high-intensity activities. A meta-analysis indicated a small but significant improvement in high-intensity exercise performance (SMD = 0.20, 95% CI: 0.01-0.39), suggesting it can be beneficial for athletes where even minor gains are important. For aerobic exercise and endurance performance, the evidence is more mixed and inconsistent across studies, with some showing benefits while others do not. The strength of evidence for high-intensity exercise is moderate, supported by meta-analyses, while for aerobic and endurance activities, it is less consistent. These benefits are thought to stem from citrulline's ability to increase nitric oxide levels, which enhances blood flow to working muscles. While the effect sizes are generally small, they can be clinically significant for competitive athletes. The benefits are often observed with acute ingestion, though long-term effects are less clear.
How it works
Citrulline's primary mechanism of action involves its conversion to L-arginine in the kidneys, which then serves as a substrate for endothelial nitric oxide synthase (eNOS). This enzyme catalyzes the production of nitric oxide (NO) in the endothelial cells lining blood vessels. Nitric oxide is a potent vasodilator, meaning it signals the smooth muscles surrounding blood vessels to relax, leading to increased blood flow. This enhanced blood flow can deliver more oxygen and nutrients to working muscles during exercise, and facilitate the removal of metabolic byproducts, potentially improving exercise performance and reducing fatigue. Citrulline is generally well-absorbed, contributing to its effectiveness in increasing systemic NO levels.
Side effects
Citrulline is generally considered safe for consumption. The most commonly reported side effects are gastrointestinal issues, such as diarrhea, particularly when consumed at very high doses. Uncommon and rare side effects are not well-documented in current research. There are potential drug interactions, especially with medications that affect blood pressure, such as nitrates or erectile dysfunction drugs, due to citrulline's vasodilatory effects; caution is advised when combining them. No well-established contraindications exist, but individuals with pre-existing medical conditions, particularly kidney disease, should exercise caution and consult a healthcare professional before use. Overall, adverse effects are infrequent and typically mild, occurring mainly at dosages exceeding recommended ranges.
Dosage
The typical minimum effective dose of citrulline is around 2-3 grams. Optimal dosage ranges generally fall between 2-10 grams per day, depending on the desired outcome and individual tolerance. For exercise performance, acute ingestion of 6-8 grams of L-citrulline or 8-12 grams of citrulline malate (which contains approximately 50-60% L-citrulline) about 60 minutes before exercise is commonly recommended. The maximum safe dose is not definitively established, but doses exceeding 10 grams may increase the likelihood of gastrointestinal side effects. While citrulline malate is a popular form, L-citrulline itself may be more effective for certain outcomes. Citrulline is generally well-absorbed, and specific cofactors are not required for its efficacy.
FAQs
When is the best time to take citrulline?
For potential exercise performance benefits, it is best taken acutely, approximately 60 minutes before your workout. Long-term effects are less clear, but consistent daily intake may support cardiovascular health.
Is citrulline safe to use?
Yes, citrulline is generally considered safe. The most common side effects are mild gastrointestinal issues, such as diarrhea, usually at higher doses. Always monitor your body's response.
What kind of results can I expect from taking citrulline?
You might experience small improvements in high-intensity exercise performance due to enhanced blood flow. Results for endurance activities are more variable. Do not expect dramatic changes in muscle strength or size.
Can citrulline interact with medications?
Citrulline can affect blood pressure due to its vasodilatory properties. If you are taking medications for blood pressure or erectile dysfunction, consult your doctor before using citrulline to avoid potential interactions.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/30895562/ – This meta-analysis investigated the effects of citrulline supplementation on high-intensity exercise performance. It found a significant but small positive effect (SMD = 0.20) across 13 samples and 198 participants, suggesting citrulline can offer a modest ergogenic benefit for high-intensity activities.
- https://pubmed.ncbi.nlm.nih.gov/36079738/ – This systematic review and meta-analysis examined citrulline's impact on aerobic exercise performance. The findings were mixed, indicating variability across studies and suggesting that while some benefits may exist, the evidence is not consistently strong for aerobic activities.
- https://www.tandfonline.com/doi/full/10.1080/15502783.2023.2209056 – This systematic review and meta-analysis focused on citrulline's ergogenic effects on endurance performance in young, healthy adults. It highlighted inconsistent findings, suggesting that the benefits of citrulline for endurance activities are not universally observed and require further research.
- https://www.tandfonline.com/doi/full/10.1080/19390211.2021.1939473 – This source provides general information on citrulline, its role in nitric oxide production, and its potential applications in exercise and cardiovascular health. It contributes to the understanding of citrulline's mechanisms and overall safety profile.
