The Ingredients in Semen

Nov 11, 2010 • Lessons


Last week, we examined why semen stings when it gets into the eye. Today we’re exploring the major components of semen:

Seminal Plasma (the liquidy part)

The main purpose of the seminal plasma is to provide a protective environment for the sperm during their long swim through the extremely hostile environment of a woman’s vagina. There’s gotta be a joke in there somewhere about harsh women, but it escapes me at the moment — possibly because I fear retribution from female readers. The plasma is made up of the following major ingredients:

Ions: Think salts and metals. Like sodium, chloride, potassium, calcium, magnesium. Wow, a virtual One-A-Day vitamin in liquid form! All of these ions contribute to the “saltiness” or the (science nerd warning) osmolality. We covered this in the last piece, although semen is a bit saltier that other bodily fluids, it’s definitely not up there with a salt-lick. It’s salty enough to possible cause a little discomfort after prolonged exposure.

Sugars Sugars are also present in semen. Like salts, sugars can cause some slight discomfort when the eye is exposed to it for a while. Can I take this opportunity to try and convince you we taste like candy? Not buying it? That’s because, while there is plenty of sugar (like fructose and sorbitol) in semen, it’s not high enough to counter the taste of other ingredients in semen (darn). The sugar level in semen isn’t really that high, so it’s probably not going to cause any discomfort.

Minor ingredients: There are several minor ingredients in semen that are either too low in concentration or are generally not irritating: lipids (or fats), steroid hormones (OMG! Cum in the eye will make you hit more home-runs!), enzymes, prostaglandin hormones, amino acids and basic amines. I can’t see (ha!) any of these causing any major irritation. The sum of all of them might do a little bit of something, but definitely not the tazer to the eye feeling people complain about when they take a shot in the eye.

Protein Carriers and Mucus (glycoproteins)

Albumin (yeah, the same stuff in egg white which is pretty pure albumin) is present at a pretty high concentration in semen. This is reported to be irritating to eyes, but I’ve seen it in eye drops, so I’d just put this as a possible culprit. I’m looking for volunteers to splash raw egg white in their eyes to test this. When you recover from the salmonella, let me know if it hurt (the egg whites, not the salmonella).

As long as we’re talking slimy, there’s also a mucus made by small bulbourethral glands that gives semen that wonderful, jelly-like texture. Bonus points to anyone who can work bulbourethral into something sexy-sounding: “Baby, you make my bulbourethral glands throb!”… er, no.


No explanation necessary. There are about 200-500 million sperm in your average ejaculation. Forget bragging about having a 10-inch penis, I wanna see your sperm count card! That’s the test of a true man! Sperm make up about 5 percent of the total semen amount. Looking back, we’re starting to pile on the proteins (enzymes, albumin, sperm). Proteins in general can be irritating. I’m starting to suspect the generally high protein amount is the possible culprit for the batter burn (more on this in a sec).

Buffering Agents

I mentioned in part one the likeness of semen to Alka-Seltzer, the normal pH of the eye is around neutral (pH 7.0 – 7.3). That’s a pretty good match for semen, so it shouldn’t cause any pain. Bausch and Lomb should tap into college guys for a cheap source of “buffer”. The chess clubs probably have the most… experience.


Looking above, what I see as possible causes of the pain are salts and proteins mainly. Salt is easily washed away, so it should only cause discomfort until you can hit the faucet. Those of you who tested the Morton’s in part one of this series can probably attest to this.

Protein, however, is sticky stuff. Rinsing generally won’t remove it well. You might rinse out the buffers, salts, lipids, etc., but the protein will be still in there. Check contact lens rinses and see how they brag about their ability to remove irritating proteins from the lenses. I suspect this is what causes the pain to linger.

Part 1: Debunking Semen Myths
Part 3: The Different Kinds of Sperm

Image by Adam Coster.