What Is In Semen

A urologist can walk you through what is needed to investigate the abnormality. This may involve a procedure known as a semen analysis if there are concerns about fertility. Other lab or imaging tests may be ordered depending on your symptoms and the suspected cause.


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Alternate titles: seminal fluid
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Last Updated: Jan 4, 2023 • Article History
Table of Contents

male reproductive organs

male reproductive organs
Related Topics: sperm ejaculation semen analysis male reproductive system . (Show more)

semen, also called seminal fluid, fluid that is emitted from the male reproductive tract and that contains sperm cells, which are capable of fertilizing the female’s eggs. Semen also contains liquids that combine to form seminal plasma, which helps keep the sperm cells viable.

human sperm cells

In the sexually mature human male, sperm cells are produced by the testes (singular, testis); they constitute only about 2 to 5 percent of the total semen volume. As sperm travel through the male reproductive tract, they are bathed in fluids produced and secreted by the various tubules and glands of the reproductive system. After emerging from the testes, sperm are stored in the epididymis, in which secretions of potassium, sodium, and glycerylphosphorylcholine (an energy source for sperm) are contributed to the sperm cells. Sperm mature in the epididymis. They then pass through a long tube, called the ductus deferens, or vas deferens, to another storage area, the ampulla. The ampulla secretes a yellowish fluid, ergothioneine, a substance that reduces (removes oxygen from) chemical compounds, and the ampulla also secretes fructose, a sugar that nourishes the sperm.

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During the process of ejaculation, liquids from the prostate gland and seminal vesicles are added, which help dilute the concentration of sperm and provide a suitable environment for them. Fluids contributed by the seminal vesicles are approximately 60 percent of the total semen volume; these fluids contain fructose, amino acids, citric acid, phosphorus, potassium, and hormones known as prostaglandins. The prostate gland contributes about 30 percent of the seminal fluid; the constituents of its secretions are mainly citric acid, acid phosphatase, calcium, sodium, zinc, potassium, protein-splitting enzymes, and fibrolysin (an enzyme that reduces blood and tissue fibres). A small amount of fluid is secreted by the bulbourethral and urethral glands; this is a thick, clear, lubricating protein commonly known as mucus.

Essential to sperm motility (self-movement) are small quantities of potassium and magnesium, the presence of adequate amounts of oxygen in the plasma, proper temperature, and a slightly alkaline pH of 7 to 7.5. Sulfate chemicals in semen help prevent the sperm cells from swelling, and fructose is the main nutrient to sperm cells.

The total volume of semen for each ejaculation of a human male averages between 2 and 5 ml (0.12 to 0.31 cubic inch); in stallions the average ejaculate is about 125 ml (7.63 cubic inches). In human beings each ejaculation contains normally 200 to 300 million sperm. Semen frequently contains degenerated cells sloughed off from the network of tubules and ducts through which the semen has passed.

The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Kara Rogers.

What Your Semen Says About Your Health

Jerry Kennard, PhD, is a psychologist and associate fellow of the British Psychological Society.

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Updated on March 16, 2022

Jamin Brahmbhatt, MD, is board-certified in urology. He is an assistant professor at UCF College of Medicine and chief of surgery at Orlando Health South Lake Hospital.

Table of Contents
Table of Contents

Semen is the cloudy, white fluid that is released from the penis during ejaculation. It consists of sperm cells (called spermatozoa ) and a nutrient-rich liquid called seminal fluid. The purpose of seminal fluid is to transport sperm cells and enable their survival for up to five days so that fertilization is possible.

This article answers some of the common questions about semen. It also explores what the color, consistency, and smell of semen say about your health.

What Is Semen?

Semen is composed of seminal fluid populated with sperm cells. With every ejaculation, about 100 million sperm cells are released from the penis.

Sperm cells are produced in the testicles. From there, the cells enter a coiled tube called the epididymis where they are stored and mature under the influence of hormones from the testicles and pituitary gland.

Thereafter, the sperm cells migrate to a long, muscular tube called the vas deferens where they combine with seminal fluid secreted by two ejaculatory ducts. The end product is semen.

Sperm production to ejaculation

The seminal fluid itself is composed of fluids from three organs:

  • Cowper’s gland is a pea-sized organ that secretes fluids that function as a lubricant and helps neutralize acids to keep sperm cells alive.
  • Prostate gland is a walnut-sized gland that secretes fluids that keep semen in a liquified state while providing nutrients and enzymes that nourish and protect sperm cells.
  • Seminal vesicles are a pair of tube-shaped glands that secrete fluids rich in fructose (a sugar that helps fuel sperm cells) and prostaglandins (a type of fat that triggers the contraction of vaginal muscles to propel the sperm up the vaginal canal).

During ejaculation, powerful contractions of muscles (called bulbospongiosus and pubococcygeus muscles) propel semen out of the penis through a long tube called the urethra.

Semen Volume

The volume of semen that is released during ejaculation can vary. A 2012 review of studies published in the Journal of Andrology suggests the average volume is 3.4 milliliters (mL). This is roughly two-thirds of a teaspoon.

Semen volume may impact male fertility. Research suggests having a higher-than-normal semen volume corresponds with a low lower sperm count. This is due to the dilution of sperm cells.

On the other hand, a lower-than-normal semen volume (less than 1.5 mL) also corresponds to a lower likelihood of fertility. Consistently low semen volumes may be due to a condition such as retrograde ejaculation in which semen flows back to the bladder rather than out of the body.

Low semen volumes may also be a sign of other medical conditions. A 2014 study in Fertility and Sterility evaluated over 9,000 males with an average age of 38. They found that people with low semen volumes were nearly two times more likely to have high blood pressure or heart disease than those with normal semen volumes.

Low semen volumes are not always a sign of infertility or illness. They can also be a sign of dehydration or recent ejaculation.

If semen volumes are consistently abnormal and you’ve been unable to conceive, you may want to consult with a fertility specialist.

Semen Taste and Smell

Semen often smells like chlorine or ammonia and tastes slightly sweet due to its high fructose content. That being said, the taste and smell of semen can vary from one person to the next.

Certain foods can alter the taste and smell of semen, making it more bitter, pungent, or musky. These may include foods like:

  • Alcohol
  • Asparagus
  • Cabbage
  • Coffee
  • Dairy
  • Garlic
  • Meats
  • Onions

Other foods are said to make semen smell or taste milder or sweeter, including celery, parsley, and pineapple.

Smoking tobacco can also alter the taste or smell of semen. In addition, cigarettes can reduce the quality, count, and motility of sperm and make it harder for your to conceive.

Another factor that can influence the smell or taste of semen is an infection. These include urinary tract infections (UTIs) and sexually transmitted diseases like chlamydia, gonorrhea, and trichomoniasis.

If your semen has a foul or “rotten” smell, it may be the first sign of a genital or urinary tract infection. Speak with a healthcare provider as soon as possible.

Semen Color and Consistency

Normal semen is generally an off-white or slightly yellow color. The consistency should be similar to that of an egg-white or be slightly jelly-like. There may sometimes be jelly-like globules in the semen, which is normal if you are dehydrated or have not ejaculated in a long time.

Changes in semen color are often of little concern, but certain colors may suggest a health problem.

Red or Brown

If your semen has a red or brown color, it may be a sign of blood. While this may seem alarming, the condition (called hematospermia ) is usually not serious.

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Causes of hematospermia include:

  • Ruptured blood vessel
  • Enlarged prostate
  • Epididymitis (inflammation of the epididymis, most often due to an infection)
  • Orchitis (inflammation of the testicle, most often due to an infection)
  • Sexually transmitted diseases
  • Testicular trauma
  • Kidney or bladder stones
  • Recent prostate biopsy
  • Recent vasectomy

The good news is that most cases of hematospermia clear on their own without incident. Rarely is blood in semen a sign of cancer.

Yellow or Green

Semen with a pronounced yellow or green color may be the sign of an infection. There are other possible causes as well.

Some of the common and uncommon causes of yellow or green semen include:

  • Sexually transmitted diseases (STDs) like chlamydia, gonorrhea, and trichomoniasis
  • Prostatitis or the inflammation of the prostate gland, often due to an infection
  • Jaundice or the buildup of a yellow pigment called bilirubin due to conditions like hepatitis and gallstones
  • Pyospermia, a condition linked to male infertility in which high concentrations of white blood cells in semen damage and weaken sperm cells)

Contact your healthcare provider if abnormally colored semen is accompanied by signs of infection (including pain, swelling, or fever) or if the symptom persists, worsens, or recurs.


Semen, composed primarily of seminal fluid and sperm cells (spermatozoa), is typically off-white or slightly yellowish with a consistency similar to egg whites. It often has a slightly ammonia-ish scent and can vary in flavor from sweet to salty to bitter.

Semen quality varies from person to person. With that said, certain issues may be a sign of an infection or infertility. These include foul-smelling semen, abnormally colored semen, or high or low volumes of semen after ejaculation. Abnormalities like these should be investigated, particularly if the symptoms are persistent or worsening.

A Word From Verywell

Talking about semen with your healthcare provider may be uncomfortable, but don’t let discomfort get in the way of your good health. If needed, ask for a referral to a urologist who specializes in diseases of the genital and urinary tract.

A urologist can walk you through what is needed to investigate the abnormality. This may involve a procedure known as a semen analysis if there are concerns about fertility. Other lab or imaging tests may be ordered depending on your symptoms and the suspected cause.

Frequently Asked Questions

How does food intake affect semen?

Diet can impact sperm quality and fertility. Studies show that diets high in processed meats, trans fat, soy, and high-fat dairy cab affect the shape, quantity, and motility of sperm. On the other hand, diets high in fish, fruits, vegetables, and walnuts are shown to increase sperm quality.

How long does it take to produce sperm?

The average life span of sperm is 74 days. After the testicles make the sperm, it takes time for them to fully mature. This process takes around two and a half to three months. After ejaculation, sperm can live inside the female reproductive tract for up to five days.

14 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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  2. Griswold MD. Spermatogenesis: the commitment to meiosis. Physiol Rev. 2016;96(1):1–17. doi:10.1152/physrev.00013.2015
  3. Alwaal A, Breyer BN, Lue TF. Normal male sexual function: emphasis on orgasm and ejaculation. Fertil Steril. 2015 Nov;104(5):1051–60. doi:10.1016/j.fertnstert.2015.08.033
  4. Barrett T, Tanner J, Gill AB, Slough RA, Wason J, Gallagher FA. The longitudinal effect of ejaculation on seminal vesicle fluid volume and whole-prostate ADC as measured on prostate MRI. Eur Radiol. 2017;27(12):5236-43. doi:10.1007/s00330-017-4905-x
  5. McKay AC, Sharma S. Anatomy, abdomen and pelvis: seminal vesicle. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2022.
  6. Maya WC, Berdugo J, Cadavid AP. Is there a close relation between sperm count and ejaculation volume?J Reprod Contracep. 2011 Mar;22(1):23-8. doi:10.1016/S1001-7844(12)60003-0
  7. Leslie SW, Siref LE, Soon-Sutton TL, Khan MAB. Male infertility. In: StatPearls [Internet]. Treasure Island, FL; StatPearls Publishing; 2022.
  8. Eisenberg ML, Li S, Behr B, Pera RR, Cullen MR. Relationship between semen production and medical comorbidity. Fertil Steril. 2015;103(1):66-71. doi:10.1016/j.fertnstert.2014.10.017
  9. Kovac JR, Khanna A, Lipshultz LI. The effects of cigarette smoking on male fertility. Postgrad Med. 2015;127(3):338-341. doi:10.1080/00325481.2015.1015928
  10. Vasan SS. Semen analysis and sperm function tests: How much to test?Indian J Urol. 2011;27(1):41-48. doi:10.4103/0970-1591.78424
  11. Mathers MJ, Degener S, Sperling H, Roth S. Hematospermia-a symptom with many possible causes. Dtsch Arztebl Int. 2017;114(11):186-91. doi:10.3238/arztebl.2017.0186
  12. Condorelli RA, Russo GI, Calagero AE, Morgia G, La Vignera S. Chronic prostatitis and its detrimental impact on sperm parameters: a systematic review and meta-analysis. J Endocrinol Invest. 2017;40(11):1209-18. doi:10.1007/s40618-017-0684-0
  13. Khodamoradi K, Kuchakulla M, Narasimman M, et al. Laboratory and clinical management of leukocytospermia and hematospermia: a review. Ther Adv Reprod Health. 2020;14:2633494120922511. doi:10.1177/2633494120922511
  14. Salas-Huetos A, James ER, Aston KI, Jenkins TG, Carrell DT. Diet and sperm quality: nutrients, foods and dietary patterns. Reprod Biol. 2019;19(3):219-224. doi:10.1016/j.repbio.2019.07.005

By Jerry Kennard
Jerry Kennard, PhD, is a psychologist and associate fellow of the British Psychological Society.

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