Get ready. All those Qs about pre-cum that you feel like you should know the answers to but aren’t actually sure, are about to be answered. (We had them too, don’t worry!)


Pre-cum, also known as pre-ejaculation, is fluid produced by a pair of pea-sized glands right underneath the prostate and behind the urethra called the Bulbourethral glands or Cowper’s glands. It’s similar to cum, but not the same.

Why does pre-cum happen?

Pre-cum is released via the tip of the penis during arousal to help lubricate the penis for a smoother penetrative process and to protect the sperm from the acidity of urine for a better chance of making it to that egg (1). #smartglands

Can STIs be transferred via pre-cum?

Yep, so stay safe out there!


Pre-cum is an enzyme-filled, mucus-containing, alkaline fluid. Even though the glands producing the pre-ejaculate fluid are not releasing sperm, oftentimes, pre-cum will have sperm in it too (5).  In one study, 37% of the subjects’ pre-cum contained motile sperm (meaning, they could still swim). Sometimes not all of the sperm leaves the penis when someone ejaculates, so some swimmers get left behind in the urethra. So, the next time that person becomes aroused and pre-cum is released, some sperm can mix in with it- warning to those who can get pregnant!

Is it the same as regular cum?

Nope! Cum (aka semen) is made of many things including salt, various proteins and amino acids, vitamin C and other antioxidants, calcium, magnesium, potassium, mucus, testosterone, and other hormones. Spermatazoa, or sperm, looks like a small head attached to a tail (like little tadpoles!) and can move around.  Sperm + Seminal Fluid = semen (or cum). And it can drip or shoot outta the penis (hello 7th grade competitions).

Pre-cum, on the other hand, is a type of seminal fluid (ingredients above).  And while it is possible for there to be sperm in it, the gland that produces the pre-cum isn’t producing sperm with it.  The sperm found in pre-cum is leftovers being swept up into the action.

How can you tell if it is pre-cum or cum?

A few ways...

  • Color + texture: Full on cum/ejaculate tends to be more of a cloudy, white, thicker fluid whereas pre-cum tends to be thinner and clear (1)

  • Smell: Semen may smell a bit like chlorine or bleach, while pre-cum is typically odorless. (3)

  • Volume: The amount of pre-cum ranges from one drop to a teaspoon (4) and cum can range from 1.5 ml to 7.6 ml, or as much as closer to a tablespoon (1).

  • Communication: Your sexual partner will be able to tell if they are ejaculating or are going to. So, while they may not be able to tell you when they pre-ejaculate, they can tell you before they fully ejaculate.  You can also always ask for them to give you a warning before they cum, and if you are ever unsure just ask!


Great question because, well, we can’t really answer it! Pre-cum can sort of happen at any time during arousal prior to full on ejaculation. Because pre-cum is involuntary, most people can’t tell when it is going to happen.

Pre-cum can also be released during a wet dream (when you’re sexually stimulated while sleeping), and this is totally normal. Hope it was a good one!

Can it happen when someone isn’t aroused?

It’s possible for semen to ‘leak’ out of a penis when it’s not aroused, this can be in the form of pre-cum or cum. This can be caused by certain medications, prostate problems, or an injury (6). Fun fact: It’s also possible to leak semen after peeing!

You’ll want to see a doctor if blood is coming out of the penis, if you’re in any pain, if your discharge smells bad, or if you notice any major differences (6). Remember, different bodies produce different amounts of fluids and it can change over time so just keep an eye out for any big changes.

Do people with vaginas pre-cum?

Well, kind of! Vaginas release all kinds of fluids. People with vaginas have Bartholin’s glands (the vagina’s pea-sized glands!) (7). Penises aren’t the only things that swell during arousal, vaginal walls do too! This pressure produces fluid, and the amount and consistency is different for every body dependent upon hormonal levels, foreplay, and where your head’s at (7).


The short answer is yes. Sperm can live for five (sometimes up to seven!) days. So, even if you didn’t ovulate exactly when you had intercourse, you can still be in your fertile window. So, if there is motile sperm in that pre-cum, it is possible to get pregnant if you are not using a barrier method and/or other form of birth control. If you scour the interwebs, you’ll see that many articles say that although pre-cum has the word “cum” in it, it typically doesn’t contain live sperm unless the person had recently ejaculated—in which case, then it is possible. But, we found multiple studies (like this study and this study) which showed otherwise.

The men* in these studies actually had motile sperm in their pre-ejaculate (the samples were tested very soon post collection, which is what, they think, accounts for the difference from previous studies which found no motile sperm), so we say: play it safe.

If you are not in your fertile window, then it is not possible to get pregnant- even from cum!


What happens if I had unprotected sex and they didn’t cum, but there was pre-cum?

Few questions to ask yourself here:

  1. Are you on another form of birth control?

  2. If you track your cycle, are you in your fertile window?

  3. What is your partner’s STI status? When was the last time they were tested?

The answers to the above question may be helpful in deciding what your next steps are, and, always check in with your provider!  

Also, check out our Ultimate Guide to Emergency Contraception!


The best ways to stay safe from pre-cum is to use a form of birth control as well as a barrier method for STI protection (unless your form of birth control does both). This means putting on the condom before the genitals come in contact with each other.  

Written by: Maya Wharton and Catherine Work

*language used in study


  1. Christiano, Donna. 2018. “Is Male Discharge Normal?” (accessed March 10 2019)

  2. World Health Organization. “WHO laboratory manual for the Examination and processing of human semen.” Fifth Edition (2010): 15-17.;jsessionid=F577E96867A29CC002AE25F470B4FFF3?sequence=1

  3. Jewell, Tim. 2018. “Is it Normal For Semen to Smell?” (accessed March 10 2019)

  4. "What is pre-ejaculate or precum?" ISSM. 21 Sept. 2018. 22 Feb. 2019.

  5. Killick, Stephen R., Christine Leary, James Trussell, and Katherine A. Guthrie. "Sperm Content of Pre-ejaculatory Fluid." Human Fertility (Cambridge, England). March 2011. Accessed March 15, 2019.

  6. Marcin, J. (2019). Semen Leakage: Causes and Treatment. [online] Healthline. Available at: [Accessed 15 Mar. 2019].

  7. McWeeney, C. (2019). Clue: Period and Ovulation Tracker for iPhone and Android. [online] Available at: [Accessed 15 Mar. 2019].