WHAT IS SEMEN MADE OF?
By Fred Guerra
Semen. It's the magical fluid that is the fruit of our labor when we masturbate. The production of semen marks the beginning of puberty for boys — a time when the body begins to grow and develop rapidly — especially the sexual organs. Ejaculations (orgasms accompanied by semen) usually begin around 12 or 13 years of age. What exactly comprises this pearly-white liquid called semen?
While we sometimes refer to semen as "sperm," sperm cells (spermatozoa) actually constitute only about 10% of our total ejaculate. That 10% contains from 200 million to 500 million sperm cells, though the figure can be higher for younger males due to the pubescent production of androgen hormones, such as testosterone, which also trigger the growth body hair and the lowering of the voice. (Remember: It takes only one sperm cell to fertilize an egg and make a baby.)
The remaining 90% is referred to as seminal plasma. (Plasma is defined as a fluid that carries a suspended solid, whether it's blood "fluid" carrying blood cells, or semen carrying sperm.) Composition of seminal plasma varies among individuals, and even in the same individual from time to time. It contains some 30 substances (many in minute quantities); some are produced by different parts of our male anatomy, and some are by-products of body functions. They include:
• ascorbic acid (vitamin C, for tissue maintenance)
• blood-group antigens (from immune system)
• calcium (mineral)
• chlorine (oxidizing agent)
• cholesterol (steroid alcohol present in body fluids)
• choline (base, part of the vitamin B complex)
• citric acid (occurs during cellular metabolism)
• creatine (nitrogenous substance found in muscle)
• deoxyribonucleic acid (DNA)
• fructose (sugar used for energy)
• glutathione (peptide amino acid)
• hyaluronidase (enzyme)
• inositol (sugar found in muscles)
• lactic acid (byproduct of muscle use)
• magnesium (mineral)
• nitrogen (gas found in all living tissue)
• phosporus (mineral)
• potassium (mineral)
• purine (compound of uric acid)
• pyrimidine (organic base)
• pyruvic acid (formed from either glucose or glycogen)
• sodium (salt)
• sorbitol (body alcohol)
• spermidine (catalytic enzyme)
• spermine (ammonia compound found in sperm)
• urea (from urine)
• uric acid (from urine)
• vitamin B12 (for proper function of nervous system and metabolism)
• zinc (mineral)
The amount of a compenent may rise or fall depending on a number of factors. For example, the amount of lactic acid may rise significantly after excercise, since it's a byproduct of muscular activity. (Lactic acid is what causes muscular soreness after exercise.) Also, food intake can significantly affect chemical makeup — and taste — of semen. By the way, it is not the spermatozoa which can contain HIV (which causes AIDS) but the seminal plasma.
Seminal plasma is partially made up of a fructose-rich fluid — produced by the seminal vesicles — which provides nourishment for the sperm cells. The seminal vesicles also make prostaglandins, unsaturated fatty acids used for hormonal actions. The prostate gland produces a thin, milky, alkaline fluid that helps the sperm live when exposed to the acidic lining of the vagina and uterus. The pea-shaped bulbourethral glands (Cowper's glands) at the base of the penis produce a fluid we refer to as "pre-cum." This is secreted to lubricate the urethra (the tube that runs through the penis) so the semen can travel more easily — however, some men do not secrete this fluid in visible quantities. (Note: For more information on the various parts of the male reproductive system, see Science Corner: Semen Production & Ejaculation.)
Actual semen quantity differs among individuals and can also change for the same individual during different times of his life. Genetics plays an important part in how much a male will ejaculate. Most males ejaculate about one teaspoon of semen. Some medications may affect the amount of semen produced. Some think that drinking more fluids will have an effect, but that belief is false. Semen is not dependent on anything external to the body, unlike urine; it is produced by the body. You will notice, however, that the longer you take between orgasms the larger the quantity of semen you will ejaculate. (You've probably noticed that if you masturbate more than once a day that the second, third or fourth time you achieve orgasm you release smaller and smaller quanitities of semen. Wait overnight and see how much more your body made while you were asleep.) Additionally, the more aroused you get and the longer you take to ejaculate, the more semen your body will produce. Foreplay — touching yourself in special ways in special places — will sometimes stimulate the body to produce more semen, since the body's reproductive glands (such as the prostate) work harder when you're aroused.
Semen from a mature male is usually a milky or pearly-white color. It is not uncommon to see a yellowish tint to the semen if you've abstained from ejaculation for a while. Semen colored with red streaks may signify blood. If you occasionally see a bit of blood it's not necessarily a cause for alarm, but if you see a lot of it, or if it persists, the condition should be brought to the attention of your physician. The same goes any other drastic color changes, which may indicate infection.