Semen: Is It Healthy to Swallow?

Medically Reviewed by Zilpah Sheikh, MD on May 18, 2024
Written by Shawna Seed, WebMD Editorial Contributor
5 min read

Semen is a complex substance created by the male reproductive organs. The fluid is made mostly of water, plasma, and mucus (a lubricating substance). It also contains 5 to 25 calories, and is made up of small amounts of essential nutrients, including:

If you perform oral sex on a male, you’ll likely take in some semen, even if you spit most of it out. Even though it’s made of many essential nutrients that you need in your daily diet, it isn’t a good nutritional source due to the small amount of semen produced in one ejaculation. Taking it in also puts you at a greater risk of getting a sexually transmitted infection.

How much protein is in semen?

Researchers who reviewed several studies on this topic concluded that the average amount of protein in semen is 5,040 milligrams per 100 milliliters. One ejaculation produces between 1.5 and 5 milliliters of semen. Five milliliters is about one-sixth of a fluid ounce.

Sperm, also known as spermatozoa, are sex cells produced by males. They fertilize eggs. Sperm develop in the testicles and carry genetic material. They're so small, they can't be seen without a microscope. 

Inside the testicles, sperm develop in small tubes, called seminiferous tubes. When you're born, the cells inside these tubes are simple round cells. They become sperm cells during puberty. Your body produces testosterone and other hormones that trigger their development.

Once you hit puberty, you produce millions of sperm cells every day. One ejaculation can contain up to 5 million sperm.

Semen is a mixture of sperm and fluids created in the seminal vesicles and the prostate gland. 

Sperm need nutrients because they must travel a great distance and withstand the harsh environment of the vagina. 

The nutrients found in semen keep the sperm alive and provide energy while they race to the egg. Their main energy source is fructose, a type of sugar.

‌The ingredients that make up semen are safe. The biggest risk when swallowing semen is getting a sexually transmitted infection. You can contract herpes, syphilis, and gonorrhea from performing oral sex.

Studies have shown it’s more difficult to get the human immunodeficiency virus (HIV) from oral sex but not impossible. Semen is also known to carry the human papillomavirus (HPV). But HPV is undetectable in semen when tested. Some strains of this virus can cause throat cancer.

‌Pay attention to the look and smell of your partner's semen. The color and smell of it will help you know if there is a problem. It should have a whitish to grayish color and faint to no smell. If the semen has a foul smell, there could be an infection or other health problem.

Red-colored semen can mean there's inflammation of the glands that produce it. Yellow or green semen can be caused by an infection, medication, or vitamins. Talk to your partner about any concerns you may have.

‌How semen tastes can also be a sign of a problem. What’s considered "healthy-tasting" semen can be different from person to person. It has been described as tasting:

  • Bitter or salty because of its higher pH level
  • Sweet because it has fructose
  • Metallic because it contains many vitamins and minerals

‌The easiest way to prevent any health complications caused by swallowing semen is to not have oral sex. You can also put a condom over the penis to prevent the semen from being ejaculated into your mouth. Another method is to stop giving oral sex before ejaculation occurs and finish stimulating your partner with your hand. This method requires you to trust your partner to warn you before they ejaculate.

If you or your partner wants you to swallow their semen, you can ask for proof of a recent test for sexually transmitted infections. But keep in mind that HPV is can't be detected in semen. 

If you’ve been in contact with semen and have any concerns, you should talk to a health care professional right away.

It's possible to be allergic to semen. The protein in semen is what triggers your immune system. The allergy mostly affects women and those assigned female at birth (AFAB). One study estimates that about 40,000 people in the U.S. are allergic to semen. But people might be reluctant to talk to their doctor about symptoms, so that number could be low. 

Another name for a semen allergy is seminal plasma hypersensitivity. This allergy can affect the skin around your genitals or any area of your body that comes into contact with semen, including your hands or mouth. 

There are two types of semen allergic reactions: 

Localized semen allergy. When you have this type, only the parts of your body that come into contact with semen are affected. You might feel stinging or burning around your genitals, hands, or lips. 

Systemic semen allergy. If you have a systemic reaction, your entire body can be affected. You might get hives, your tongue and lips might swell, and you might have trouble breathing. In the most serious cases, you'll show signs of anaphylactic shock, a potentially life-threatening condition. 

You can get a semen allergy suddenly. It might develop after menopause or after you give birth. You might have it with one partner but not another. 

Symptoms will usually start within 30 minutes of contact. They can last several hours or several days.

If you get a rash after contact with semen, that doesn't necessarily mean you're allergic to it. Your doctor can help you find out what's causing your reaction. 

The simplest way to avoid an allergic reaction to semen is to use a condom during sex. Taking an antihistamine, such as Benadryl, can ease symptoms.

Some people are allergic to their own semen. This is a rare condition. It's also called post-orgasmic illness syndrome.

Semen contains fewer than 25 calories and small amounts of basic nutrients. It's not a good nutritional source, because the amount of nutrients in each ejaculation is low. Swallowing semen can put you at risk of getting sexually transmitted infections. Some people are allergic to semen; reactions can range from stinging and burning when semen comes into contact with skin to hives and trouble breathing.

How much sperm is in precum?

Pre-ejaculatory fluid is the scientific name for this substance, which is released from the penis before ejaculation. One small study found that most pre-ejaculate contains a small amount of sperm. The amount varies among different people. 

What is the nutritional value of semen?

Semen contains small amounts of nutrients such as magnesium, calcium, and zinc. But the amounts are very low. 

Is sperm high in protein?

Semen, the fluid that carries sperm, contains a small amount of protein.