L-citrulline is an amino acid that occurs naturally within the body and in various foods. It plays a role in several metabolic pathways, including the urea cycle, which helps remove ammonia from the body, and the production of nitric oxide. Nitric oxide is a molecule that influences blood vessel dilation, thereby impacting blood flow. This article provides an overview of L-citrulline’s safety profile, potential side effects, and considerations for its use.
Overall Safety Profile
L-citrulline is generally considered safe for most healthy individuals at typical supplemental doses. It occurs naturally in foods like watermelon, squash, and chickpeas, and the body also produces it. Human studies indicate L-citrulline is well-tolerated, with a low occurrence of serious adverse effects. For instance, some research suggests individuals have tolerated doses up to 15 grams over an eight-hour period without significant side effects.
Possible Side Effects and Drug Interactions
While generally well-tolerated, L-citrulline can lead to mild side effects, primarily affecting the gastrointestinal system. These may include nausea, indigestion, or diarrhea. These effects are not severe and often resolve with reduced dosage or discontinuation.
L-citrulline’s impact on nitric oxide production means it can interact with certain medications, particularly those affecting blood pressure. Individuals taking nitrates for heart conditions, such as nitroglycerin, should avoid L-citrulline, as the combination can lead to a dangerous drop in blood pressure. Similarly, it can interact with phosphodiesterase-5 inhibitors used for erectile dysfunction, like sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra), potentially causing excessively low blood pressure. Caution is also advised for those on any type of blood pressure-lowering medication, as L-citrulline may enhance their effects.
Special Considerations for Use
Certain groups should exercise caution or avoid L-citrulline due to potential risks or insufficient research. Individuals with pre-existing medical conditions, particularly kidney or liver conditions, should consult a healthcare professional before use. The kidneys are responsible for converting L-citrulline into L-arginine, so impaired kidney function could alter its metabolism. While L-citrulline assists in ammonia elimination, people with rare metabolic disorders affecting the urea cycle should seek medical advice due to the complex interplay of amino acids in these conditions.
Pregnant or breastfeeding individuals are advised against using L-citrulline supplements, as there is not enough research to establish its safety in these populations. The effects on fetal development or infant health through breast milk are not well understood, making a cautious approach advisable. Similarly, the safety and efficacy of L-citrulline in children have not been adequately studied, so its use in pediatric populations is not recommended without specific medical guidance.
Guidelines for Safe Use
For safe consumption of L-citrulline, it is recommended to start with lower doses and gradually increase them to assess individual tolerance. Daily dosage ranges in studies vary, but a common range for L-citrulline is between 1 to 6 grams per day, often around 2-3 grams depending on the intended use. For L-citrulline malate, which is 56.64% citrulline, a common dose is 8 grams.
Always adhere to product label instructions for any L-citrulline supplement. Before incorporating L-citrulline into a routine, especially if underlying health conditions exist or other medications are being taken, consulting with a healthcare professional is important. Sourcing supplements from reputable manufacturers is also important to ensure product quality and purity.