In everyday use, ejaculate and semen mean the same thing. Sperm are only a small part of it. Around 65% of the fluid comes from the seminal vesicles, about 25% from the prostate, roughly 10% from the testicles and epididymis, and about 1% from the bulbourethral (Cowper's) glands1. The fluid part as a whole is called seminal plasma.
Ejaculation happens in two linked stages. First, nerve signals close the neck of the bladder and move sperm and gland fluids into the urethra, a stage called emission. Then rhythmic contractions of the muscles around the urethra and pelvic floor push the fluid out4. If the bladder neck does not close, semen can go backwards instead, which is retrograde ejaculation.
An ejaculate is not mixed evenly. The first spurts carry most of the sperm, blended with prostate fluid, while later spurts are dominated by seminal vesicle fluid2. That is one reason labs ask you to collect the whole sample.
Orgasm and ejaculation usually happen together, but they are separate events. Orgasm is the feeling; ejaculation is the physical release of fluid. That is why it is possible to have an orgasm with little or nothing coming out, and to ejaculate with a muted orgasm.
What is ejaculate made of?
Mostly gland fluids, with sperm making up a small fraction. Each gland adds different ingredients that fuel, carry or protect sperm.
The main contributors and what they add1:
- Seminal vesicle fluid: fructose (a sugar sperm use for energy), prostaglandins and semenogelins, the proteins that make semen thicken.
- Prostate fluid: zinc, citrate and enzymes including PSA (prostate-specific antigen), which thins semen after ejaculation.
- Testicular and epididymal fluid: the sperm themselves.
- Bulbourethral gland fluid: a small amount of slippery mucus, the same source as pre-ejaculate.
Why does ejaculate go thick and then watery?
Semen forms a loose gel straight after ejaculation and then liquefies, usually within about 15 to 20 minutes. This is normal and helps release the sperm.
Semenogelins from the seminal vesicles form the gel, trapping sperm. Enzymes from the prostate, chiefly PSA, then break those proteins down1. When semen is collected in separate fractions, the early prostate-rich spurts do not clot, while the later seminal vesicle-rich spurts do2.
A few jelly-like lumps are common and usually nothing to worry about. A lab will note if a sample fails to liquefy, because that can hold sperm back.
How much ejaculate is normal?
The WHO's current lower reference limit is 1.4 mL per ejaculation. Amounts vary a lot between men and from day to day.
The 1.4 mL figure is the 5th centile in fertile men3. The biggest everyday influence on your own volume is how long it has been since you last ejaculated. See semen volume and ejaculatory abstinence for the detail.
When is a change in ejaculate worth checking?
Most changes in amount or thickness are harmless and short-lived. A few signs are worth a conversation with a doctor.
Book an appointment with your GP if you notice:
- Little or no fluid at orgasm, or cloudy urine afterwards, which can point to retrograde ejaculation4.
- Blood in your semen, or pain when you ejaculate, both recognised ejaculatory conditions that deserve assessment4.
- A lasting drop in volume alongside difficulty conceiving.
- Discharge from the penis outside of sex, or pain or burning when you pee, which can signal an infection.
Common questions
Is ejaculate the same as semen?
Yes. Ejaculate is simply the semen released at a single ejaculation. Doctors and labs often say ejaculate when talking about one sample.
Can you orgasm without ejaculating?
Yes. A dry orgasm can happen when semen goes backwards into the bladder (retrograde ejaculation) or when little or no semen is released at all. If it is new for you, mention it to a doctor.
Why is my ejaculate thicker some days than others?
Thickness depends on the balance of seminal vesicle and prostate fluid and on how long it has been since you last ejaculated. Semen that has been sitting for a while will also have liquefied and look thinner.
Read more on this
Sources
- Anamthathmakula P, Winuthayanon W. Mechanism of semen liquefaction and its potential for a novel non-hormonal contraception. Biol Reprod. 2020;103(2):411-426. PubMed
- Rodriguez-Martinez H, Martinez EA, Calvete JJ, et al. Seminal plasma: relevant for fertility? Int J Mol Sci. 2021;22(9):4368. PubMed
- Campbell MJ, Lotti F, Baldi E, et al. Distribution of semen examination results 2020 - A follow up of data collated for the WHO semen analysis manual 2010. Andrology. 2021;9(3):817-822. PubMed
- Parnham A, Serefoglu EC. Retrograde ejaculation, painful ejaculation and hematospermia. Transl Androl Urol. 2016;5(4):592-601. PubMed
Not medical advice. Written by Eric Stephens from the research cited above; not reviewed by a doctor. If something worries you, see a GP.