Semen

The fluid released from the penis during ejaculation. Contains sperm and other fluids.

Semen is the white fluid that comes out of the penis when someone ejaculates (finishes). It contains sperm, which can cause pregnancy if it gets inside someone's body.

Simplify

Semen is the fluid that comes out of the during . It's a mix of (the reproductive cells) and fluids from the gland and seminal vesicles. Sperm only make up a small fraction of semen — the rest is fluid designed to nourish and transport them. Semen is what can cause if it enters the and reaches an .

Semen is the fluid ejaculated from the penis. It contains sperm plus other fluids.
The average ejaculation produces about 2-5ml — roughly a teaspoon. [CHECK: commonly cited volume]
It's usually whitish or greyish, with a slightly thick, sticky texture that becomes more liquid after a few minutes.
It has a mild smell, often described as slightly chlorine-like or musky.
Semen can transmit including , , , and .

What's in it

Semen is made up of several components mixed together at the moment of ejaculation:

Sperm — produced in the . About 200-500 million per ejaculation, but they make up less than 5% of the total volume. [CHECK: sperm count range]
Seminal fluid — from the seminal vesicles. Makes up the majority of semen and contains fructose (sugar) to feed the sperm.
Prostatic fluid — from the prostate gland. Slightly alkaline, which helps protect sperm from the acidic environment of the vagina.
contribution — from the . A small amount of clear fluid that helps lubricate and neutralise the before ejaculation.

What it looks like

Fresh semen is usually white or greyish-white, sometimes with a slightly yellowish tint. It comes out thick and slightly clumpy, then liquefies within 5-30 minutes — this is normal and is the semen changing consistency to help sperm swim. The texture, colour, and amount can vary from person to person and from one ejaculation to the next.

Slightly yellow semen is usually normal (especially if it's been a while since the last ejaculation). If semen is consistently pink, red, or brown, that could mean blood is present — which is usually harmless but worth getting checked by a GP.

Things people get wrong

"More semen means more fertile." The volume of semen doesn't directly indicate . What matters is the sperm count and quality within it, which you can't assess by looking.

"Semen and sperm are the same thing." They're not. Sperm are the microscopic cells. Semen is the fluid that carries them. Someone who has had a vasectomy still ejaculates semen — it just doesn't contain sperm.

"Swallowing semen is dangerous." It's not harmful to swallow semen, though it can transmit STIs (like gonorrhoea or ) if the person has an infection. Whether you swallow, spit, or avoid it altogether is a personal choice.

"You can tell if someone has an STI from their semen." You can't. Most STIs don't change how semen looks. The only way to know is testing.

Things people ask about semen

Is it normal for semen to smell?

Yes. Semen has a natural mild smell — often slightly bleachy or musky. This is normal. A very strong, unpleasant, or fishy smell could indicate an infection and is worth mentioning to a GP.

Why does the amount vary?

Hydration, time since last ejaculation, level, age, and general health all affect volume. More time between ejaculations usually means more semen. None of these variations are a concern.

Can you be allergic to semen?

Rarely, but yes — semen allergy (seminal plasma hypersensitivity) exists. Symptoms include redness, swelling, itching, or burning where semen contacts the skin or inside the vagina. It's uncommon but treatable. [CHECK: prevalence and treatment options]

Does diet affect how semen tastes?

There's a common claim that things like pineapple, fruit, and plenty of water make semen taste sweeter, while caffeine, alcohol, and processed food make it taste more bitter. There's limited scientific evidence for this, but it's widely reported anecdotally.

Semen is the whitish fluid that comes out of the when someone ejaculates (finishes). It's a mix of and other fluids. Sperm are the tiny cells that can cause if they reach an inside someone's body. But sperm only make up a small part of semen — the rest is fluid that helps carry and protect them.

The amount that comes out each time is usually about a teaspoonful. It comes out thick and sticky, then becomes more liquid after a few minutes. That's normal.

Semen is usually white or greyish-white. A slightly yellow colour is also normal. It has a mild smell, often a bit like chlorine or something musky.

The amount, colour, and thickness can change depending on how much water you've drunk, how long it's been since you last ejaculated, and other things. These changes are normal.

Semen can carry infections that are passed on through sex. You can't tell by looking at it whether someone has an infection. The only way to know is testing.

Semen and sperm aren't the same thing. Sperm are the tiny cells inside the fluid. Semen is the fluid that carries them.

Sperm

Male reproductive cells produced in the testicles. Sperm fertilises an egg to cause pregnancy.

Sperm are tiny cells made inside a boy's or man's balls. They're far too small to see without a microscope. If a sperm reaches an egg inside someone's body, pregnancy can start.

Ejaculation

When semen is released from the penis, usually during orgasm.

Ejaculation is when a white fluid called semen comes out of the penis. It usually happens during an orgasm (the strongest feeling of pleasure during sex). The fluid contains sperm, which can cause pregnancy.

Pre-ejaculate

Clear fluid released from the penis during arousal, before ejaculation. Can contain small amounts of sperm.

Pre-ejaculate (pre-cum) is clear, slippery fluid that comes out of the penis when someone is turned on, before they finish. It can contain small amounts of sperm, so pregnancy is possible from it.