Precum is formally called pre-ejaculatory fluid or pre-seminal fluid in medical settings. You may also see it referred to as pre-ejaculate. It’s produced by the bulbourethral glands, also known as Cowper’s glands, which are two pea-sized glands located near the base of the penis.
Why It Has So Many Names
The casual term “precum” is widely understood, but healthcare providers and researchers use more specific terminology. “Pre-ejaculatory fluid” describes its timing (before ejaculation), while “pre-seminal fluid” distinguishes it from semen itself. The glands that produce it carry the name of William Cowper, the anatomist who first described them in the late 1600s, which is why you’ll sometimes hear the fluid called Cowper’s fluid or Cowper’s gland secretion.
What Pre-Ejaculatory Fluid Actually Does
This fluid serves a few specific purposes during sexual arousal. Its primary job is chemical: urine leaves an acidic residue inside the urethra, and sperm can’t survive in acidic conditions. Pre-ejaculatory fluid is alkaline, so it neutralizes that residue before ejaculation, creating a safer pathway for sperm.
It also helps neutralize the naturally acidic environment inside the vagina, giving sperm a better chance of surviving after ejaculation. On top of that, the fluid contains glycoproteins that act as a natural lubricant during intercourse.
Physical Characteristics
Pre-ejaculatory fluid is clear or slightly translucent, with a slippery, mucus-like consistency. It looks and feels noticeably different from semen, which is thicker and whitish. The volume varies from person to person, but studies have measured up to 4 milliliters released during arousal, roughly less than a teaspoon. Some people produce barely a drop, while others produce enough to notice easily.
Can It Cause Pregnancy?
This is one of the most common questions about pre-ejaculatory fluid. The glands that produce it do not generate sperm on their own. However, sperm from a previous ejaculation can linger in the urethra and get picked up by the fluid as it passes through. This is one reason the withdrawal method (pulling out before ejaculation) isn’t considered highly reliable. The World Health Organization puts the withdrawal method’s failure rate at 4% with perfect use and 22% with typical use, meaning roughly 1 in 5 couples relying on it in real-world conditions will experience a pregnancy within a year.
STI Transmission Risk
Pre-ejaculatory fluid can carry sexually transmitted infections. HIV.gov lists pre-seminal fluid alongside semen, blood, and other body fluids as a direct route for HIV transmission when a person has a detectable viral load. Other infections like gonorrhea and chlamydia can also be present in the fluid. This means STI transmission is possible even without full ejaculation, which is why barrier methods like condoms provide protection that withdrawal does not.