The Boxer Short Is a Pyjama

Are boxer shorts good underwear? They are cut from the same pattern as pyjama shorts and sold on a health claim the evidence never backed. Where they belong.

By Keith · 29 July 2026 · 11 min read

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Put a pair of woven boxer shorts and a pair of pyjama shorts flat on a table, both washed, both with the labels cut out, and ask a tailor which is which. He will look at the hem length and guess, because there is nothing else to go on.

Both are cut from woven shirting with no stretch in it. Both are drafted with a great deal of ease, because a fabric that does not stretch has to be given room instead. Both have two side seams, a curved or flat seat, a fly of some description, and a waistband that is a length of elastic in a fabric tunnel. Neither has a gusset. Neither has a pouch. Neither has any component whose job is to hold anything anywhere.

That is not a coincidence and it is not an insult. They are the same garment. One of them has spent forty years being sold as underwear.

The word itself gives the game away. Pyjama arrives in English around 1800 from Hindi, and before that from Persian pae jamah, which translates roughly as leg clothing: loose trousers tied at the waist, worn in India and picked up by Europeans there, largely for sleeping in. Shorten the leg and you have the object under discussion.

This is not the argument that the boxer short is bad. It is very good, and I will spend a decent part of this article saying so sincerely. The claim is narrower and more annoying: for thirty years the English-speaking world used a piece of sleepwear as its default working underwear, on the strength of one advertisement and one health rumour, and almost nobody noticed.

What the pattern block tells you

A base layer has three jobs. It moves moisture off the skin. It holds the anatomy in a settled position so the outer garment is not doing the moving. And it sits between you and your trousers so neither one ruins the other.

The woven boxer does the third job. That is the whole list.

It cannot do the second, because there is no structure in it to do it with. No pouch, no contour seam, no gathering, no gusset, nothing a maker of briefs would recognise as construction Anatomy of a Brief: Every Panel, Seam and Stitch Explained. The garment is three or four flat pieces joined at the sides, and all the shaping it will ever have comes from having been cut big cotton rib brief.

It does the first job less well than people assume. Woven cotton is absorbent, which sounds like a virtue and is the opposite of one in a base layer, because absorbent means it takes moisture in and holds it against you until air moves it out The Sweat Article: Moisture-Wicking Fabrics, Explained Properly. Where the boxer genuinely wins is airflow, and airflow only helps when there is air, which is why the garment feels superb at home in shorts and merely damp under a suit trouser in August.

None of this is a manufacturing failure. All of it is what you get when you draft a garment in a non-stretch woven fabric with a lot of ease. It is the correct output of that brief. It is simply not the brief that underwear is written to.

The bunching is geometry and no brand can fix it

Every man who has worn woven boxers under a modern trouser knows the sensation, and most of them blame the pair rather than the physics.

A trouser leg has a fixed internal circumference at the thigh. A boxer leg, cut in a fabric with no give, has a circumference of its own that must be larger than your thigh or the garment would not go on. In almost any trouser cut in the last twenty years, the boxer leg is wider than the space available. Fabric cannot compress. It has one remaining option, which is to fold.

Woven cotton folds into a ridge, and a ridge under a seam is where chafing starts. Then it migrates, because nothing is anchoring it, usually towards the seat and the inside of the thigh, which are the two places you least want a rope of shirting to be at eleven in the morning VPL, Static and Other Trouser Problems.

The market's answer has been to sell knitted boxer shorts, which are a T-shirt fabric cut to a boxer pattern. They bunch less. They are also much less pleasant on a hot night, because the airflow you were buying the style for has been traded away, and at that point you have paid for a compromise when a trunk would have given you a better one The Trunk Is the Sweet Spot.

If you like boxer shorts, buy woven. If you want a boxer that works under trousers, you do not want a boxer.

The health claim, which was thinner than anyone admitted

Ask a man over fifty why boxer shorts took over and he will tell you about sperm. He will not have a study in mind. He will have the shape of a study, absorbed sometime around 1990, which said that tight underwear cooks you and loose underwear does not.

The evidence has always been softer than the confidence.

The most awkward paper for the folk wisdom is from 1998, when Munkelwitz and Gilbert published a study in the Journal of Urology under the wonderfully blunt title "Are boxer shorts really better?". They took 97 men attending for subfertility and measured scrotal, core and skin temperature. Mean scrotal temperature came out at 33.8 degrees in the boxer group and 33.6 degrees in the brief group. Semen parameters showed no significant difference either. Their conclusion was that the hyperthermic effect of brief style underwear had been exaggerated and that routinely telling infertility patients to switch was not supported.

Twenty years later the Harvard study everyone half remembers found the opposite direction, with boxer wearers showing meaningfully higher sperm concentration, and it has real limitations of its own that this site has already gone through line by line Do Briefs Affect Fertility? What the Study Actually Says. A recent narrative review in Translational Andrology and Urology, surveying the whole literature, lands somewhere unglamorous and probably correct: the associations are modest, they are inconsistent, the prospective data on actual pregnancy shows no significant difference, and underwear choice alone is unlikely to meaningfully influence anyone's outcome What Doctors Actually Say About Underwear.

What interests me is not the biology. It is that for three decades a garment was sold to men as a medical decision, in a category where men already find it difficult to have preferences out loud. A health claim is a wonderful thing to sell underwear on, because it lets a man buy something without admitting he chose it. He is not expressing a taste. He is following advice.

The other half of the story is sixty seconds long and has been told on this site already, so I will be brief about it.

In 1985 a Levi's commercial put Nick Kamen in a launderette in a pair of white woven boxer shorts, and British men who had worn briefs their whole lives went out and bought boxers Launderette: The Sixty Seconds That Rewrote Men's Underwear. The garment in that film does nothing. It has no feature, solves no problem and is never once explained. A stylist chose it because it read as relaxed next to the formality of a brief, and an entire national category turned over on that reading.

Put the two together and you have the foundation of thirty years of default: a styling decision and a rumour. Not a fabric breakthrough, not a patent, not a change in how men worked or dressed. The strangeness of that has worn off only because it happened slowly enough to feel like weather.

Now the case for it, made properly

I own boxer shorts. I would defend them against anyone, including me.

In bed. If you sleep in something, this is the correct thing to sleep in, and the reason is thermal. Core temperature falls overnight and climbs again towards morning, and a loose woven layer handles that swing better than anything close fitting. That the boxer short is superb at this is not a surprise. It is a pyjama. Being a pyjama is the point.

In real heat. Under a wide linen trouser, in a climate where the air actually moves, a woven boxer is cooler than a boxer brief and it is not close. This is why the style has never gone away in hot places and never will.

At home. There is no argument to have here. An hour in washed cotton boxers at the end of a long day is one of the reliable small pleasures, and a magazine too serious to say so would be missing something In Praise of the Loose Boxer.

If you actively dislike compression. Some men do. Not out of squeamishness, not because they have never tried the alternative, but because the sensation of anything holding them is unpleasant and stays unpleasant. That is a preference about your own body and it does not require a defence, a study or a fourteen-day trial. If close-fitting underwear makes you miserable, the correct underwear is the one that does not, and everything above about geometry and moisture is a set of trade-offs you are entitled to accept knowingly.

There are also medical reasons, post-surgical reasons and skin conditions where loose woven cotton is what you have been told to wear, and nobody in that position needs a magazine's opinion about pattern blocks.

Buying a good one, since you should own some

Buy the version that is actually good rather than the version that is a knitted compromise.

Woven, not knitted. Poplin in the summer, brushed cotton or a light flannel in the winter woven cotton boxer short brushed cotton boxer short. Madras and gingham exist for a reason and that reason is that they look magnificent hanging on a chair.

A wide, covered waistband rather than a narrow exposed one. A garment with this much fabric hanging off the band puts real load on it, and narrow elastic in a boxer rolls within a year.

A fly that fastens. The boxer is the one style where the fly does structural work rather than acting as a design flourish, and a gaping fly on a badly drafted pair is the single most common complaint in the category.

A curved seat panel, because cheap boxers are cut flat and pull across the back the moment you sit down. And buy your real waist: the garment is not held on by tension, so sizing up simply gives the elastic more to do.

The claim, stated plainly

What I actually want is not that anyone stops wearing boxer shorts. I want them re-shelved.

The woven boxer short should be sold, bought and thought of as what its pattern says it is: excellent loose sleepwear that a man can also wear about the house and on the hottest week of the year. Not the default. Not the thing you put on at seven in the morning under a work trouser without ever having considered an alternative, which is what a great many men in Britain, Ireland, America and Australia are still doing on the strength of a jeans advert and a half-remembered headline.

Own three or four pairs and buy them on purpose. Wear them in the evening, in bed, in August, the day after the marathon. Then keep something with actual construction in it for the working day, whether that is a brief, a trunk or a boxer brief, all three of which were drafted by someone who knew the garment would spend its life inside a trouser The Case for Briefs: Why They Should Be Every Man's Default.

The boxer short has been badly served by being made into a symbol, first of relaxed masculinity and then of not trying. It is neither. It is a very good pair of loose cotton shorts with an unusual career, and it deserves to be allowed to go home.

Questions people ask

Are boxer shorts actually bad underwear?

They are not bad, they are miscast. A woven boxer short has no pouch, no gusset and no stretch, so it offers no support and it bunches inside any trouser cut narrower than it is. Those are properties of a loose woven garment rather than defects in any particular pair. For sleeping, for hot still weather and for wearing at home, the boxer short is genuinely the best thing in the drawer. For a working day inside trousers, almost anything with construction in it will serve you better.

Do boxer shorts really help fertility?

The evidence is much weaker than the reputation. A 1998 study in the Journal of Urology found essentially identical scrotal temperatures in boxer and brief wearers and concluded that the heating effect of briefs had been exaggerated. A 2018 Harvard study found higher sperm concentration among boxer wearers, but it was cross-sectional, self-reported and drawn from men attending a fertility clinic. A recent narrative review concludes that underwear choice alone is unlikely to meaningfully affect fertility outcomes. If heat is a genuine concern, speak to a doctor rather than to your drawer.

Can you wear boxer shorts under a suit?

You can, and men did for fifty years, but they were wearing far wider trousers than most suits are cut with now. A woven boxer needs room around the thigh, and a slim or tapered leg does not have it, so the fabric folds and then travels. If your suit trouser has real width and a proper break, a woven boxer is comfortable and cool. In anything modern and close, expect bunching and expect to notice it by lunchtime.

Why do boxer shorts bunch up under trousers?

Because a non-stretch woven garment has to be cut wider than your thigh to go on, and most trouser legs are narrower than that. Fabric cannot compress, so it folds, and once folded it twists and migrates. No brand solves this, because it is geometry rather than quality. Knitted boxers bunch less but give up the airflow that makes the style worth wearing, which is why a trunk is usually the better answer cotton trunk.

What is the difference between boxer shorts and pyjama shorts?

Very little beyond hem length and marketing. Both are cut in non-stretch woven fabric with generous ease, both are built from a handful of flat panels with side seams and an elasticated waistband, both usually have a fly, and neither has a pouch or a gusset. Pyjama shorts are often cut slightly longer. If you have ever slept in your boxer shorts and thought them perfect for it, that is because you were using the garment for the job its pattern was drawn to do.