(210) Clitoral Blood Flow After Use of Gel Containing L-Arginine and L-Citrulline

Abstract

Abstract Introduction L-arginine and its precursor, l-citrulline, are two amino acids involved in the production of nitric oxide (NO); as a result, they increase blood flow and have been used to treat male sexual dysfunction (Alatas and Yagci, 2004). Some lubricants and gels contain l-arginine and are applied directly to the genital area to increase blood flow. Although these products have been evaluated subjectively through patient reports of increased warmth, arousal, and orgasm, to our knowledge, they have not been evaluated quantitatively in women. Moreover, the effect of gels combining both l-arginine and l-citrulline have not been reported in the medical literature. Objective To evaluate whether a topical gel containing l-arginine and l-citrulline increases blood flow to the clitoris. Methods Sonography of the clitoris was performed on a healthy 32-year-old volunteer before and after applying the gel externally to the vulva. The “before” scans were obtained using a neutral ultrasound gel (without l-arginine or l-citrulline). This allowed us to verify that the observations were due to the active ingredients of the gel, and not from massage associated with its application. Control images without gel could not be obtained, since acquisition of ultrasound images requires ultrasound gel in order to reduce acoustic impedance. The scans were obtained with a Philips Lumify™ ultrasound (Koninklijke Philips N.V., Amsterdam, Netherlands) with a L12-4 linear array transducer (4-12 MHz). Clitoral blood flow was assessed qualitatively (color Doppler images), as well as quantitatively (peak systolic velocity, end diastolic velocity, and resistive index of the deep artery of the clitoris). Results Blood flow to the clitoris increased after application of the gel containing l-arginine and l-citrulline at both evaluated time points. The maximum PSV of the deep artery of the clitoris also increased from 6.2 cm/s (before), to 8.6 cm/s (5 minutes) and 13.9 cm/s (15 minutes). The maximum EDV of the deep artery of the clitoris increased from 1.4 cm/s (before), to 1.7 cm/s (5 minutes) and 9.5 cm/s (15 minutes). The RI was 0.8 before and at 5 minutes. After 15 minutes, the RI decreased to 0.3, explained by a disproportional increase in EDV compared to PSV. Conclusions The results of this pilot study suggest that clitoral blood flow increases with the use of a gel containing l-arginine and l-citrulline. These findings can help clinicians inform patients with female sexual dysfunction. Difficulty achieving clitoral stimulation is a major cause of sexual dysfunction. Clinicians can use these findings to counsel patients about using gels to increase clitoral blood flow. Disclosure No