Pre-ejaculate (also known aspre-ejaculatory fluid,pre-seminal fluid orCowper's fluid, and colloquially aspre-cum) is a clear, colorless,viscous fluid that is emitted from theurethra of thepenis duringsexual arousal and in general duringsexual activity. It is similar in composition tosemen but has distinct chemical differences. The presence ofsperm in the fluid varies from low to absent. Pre-ejaculate functions as a naturallubricant and anacid neutralizer.
The fluid is discharged from the urethra of the penis duringarousal,masturbation,foreplay or at an early stage duringsexual intercourse, some time before the individual fully reachesorgasm and semen isejaculated. It is primarily produced by thebulbourethral glands (Cowper's glands), with theglands of Littré (the mucus-secreting urethral glands) also contributing.[1][2] The amount of fluid that is issued varies widely among individuals. Some individuals do not produce any pre-ejaculate fluid,[3] while others emit as much as 5 ml (0.18 imp fl oz; 0.17 US fl oz).[1][4]
Pre-ejaculate fluid contains chemicals associated with semen, such asacid phosphatase, but other semen markers, such asgamma-glutamyltransferase, are absent.[5]
Pre-ejaculate neutralizes acidity in the urethra caused by residualurine, creating a more favorable environment for the passage of sperm.[2] Thevagina is normally acidic, so the deposit of pre-ejaculate before the emission of semen may change the vaginal environment to promote sperm survival.[1] Pre-ejaculate also acts as a lubricant duringsexual activity,[1] and plays a role in semen coagulation.[1]
Low levels or no sperm exists in pre-ejaculate, although studies examined small samples of men.[4][6] Two contrary studies found mixed evidence, including individual cases of a high sperm concentration.[7][8] There is evidence – dating to a 1966Masters and Johnson study[9] – that pre-ejaculate may contain sperm that can cause pregnancy, which is a common basis of argument against the use ofcoitus interruptus (withdrawal) as a contraceptive method.[4][6]
Studies have demonstrated the presence ofHIV in most pre-ejaculate samples from infected men.[6][10][11]
In rare cases, an individual may produce an excessive amount of pre-ejaculate fluid, which may be treatable by a5-alpha-reductase inhibitor, such asfinasteride.[1]
.svg)