I bought a casual 100% cotton button-down shirt the other day from the brand ESP fashion.

I live in Bangkok, Thailand and it's crazy hot here at the moment (or any moment), so I figured a white one would probably A) not be as hot in the sun and B) not show sweat as easily as other colors.

Anyway, in the fitting room the shirt was really nice, soft and appeared to be a bit moisture-repellant. Got home, put it in the washer to get rid of possible left-over chemicals from manufacturing (it's just something I have a habit of always doing when I buy new clothes). After washing I noticed it wasn't as soft as before, so I figured they had perhaps used some softener on it (which I generally don't ever use).

The next day I put the shirt on, and my back was still a bit moist from the shower. Now the shirt immediately absorbed any moisture it came into contact with, even for just a fraction of a second! My theory that white wouldn't change color when wet got immediately debunked - it looked bad, really bad.

My theory is that the fabric was treated with something to make it a bit softer and to repel moisture, but that treatment/coating was washed away even after the first washing. So now I'm wondering if there are any products one can use to make clothes repel moisture better? Obviously, one can wax them as I have done in the past with hiking gear, but that doesn't really seem appropriate for a nice looking button-down shirt that is meant for urban use. Anything better suited for nice looking clothes? Are there any softeners or other products one can use in the washer to aid in moisture repelling?

  • What material is the shirt made from?
    – Flint
    Commented Jun 15, 2017 at 5:16
  • @Flint It's 100% cotton (I updated the question and title)
    – Magnus
    Commented Jun 15, 2017 at 6:37

3 Answers 3


There are many commercial products to "waterproof" cotton, such as Nikwax Cotton Proof, Scotchgard and Kiwi Camp Dry, my personal experience has been that these treatments are temporary (often removed by the first wash) and not too effective (direct contact with a wet object or impact of raindrops penetrates the garment). That said, one of these products might be good enough for casual wear of the shirt, being reapplied as needed. Some fabric softeners also afford a bit of water repellency; you'll need to test one.

Waxing cotton does make it waterproof, but it also makes it a fire hazard, as well. An ember from a campfire can turn a shirt or tent into a torch!

(BTW, I've yet to find a truly waterproof garment that was wearable for more than an hour or two, because humidity inside leaves me drenched. The best so far are ponchos or cagoules, open at bottom.)


In the heat you need to sweat. A lot. Or you overheat. That sweat needs to evaporate to cool you. Completely waterproofing a shirt blocks that water transport. Making you sweat even more because there is no cooling. Your plan will lead into a quite viciously backfiring circle.

White is actually one of the better choices to keep the optical effect minimal. Sweat will also not show as much with black or colourful patterns.

If the shirt you have was soft and a bit 'moisture repellent' then it was treated with any oily fabric softener. Quite ordinary stuff. The effect being just that of wax cotton in principle but weaker. That softener was likely applied only for the softening effect. The diminished wicking capability being just a side effect.

If you really want to go that route (back) just use copious amounts of fabric softener. That ruins bath towels quite quickly, making them much less absorbent.

You should look for other garments. Breathable, stiff, thick, water transporting. Linen, hemp or wool are known to be good at this. Cotton being most of the time of a too short staple to compete. Polyester like CoolMax performs good but starts to smell really quickly and is an even nastier fire/burn hazard than waxed cotton. And worry less about sweating. It made us humans successful hunters. Just wash yourself in time occasionally.

  • While this is true, it doesn't answer the question.
    – Chenmunka
    Commented Aug 31, 2017 at 7:47
  • "In the heat you need to sweat." — Not necessarily. I can't speak for Bangkok, but I have visited nearby Singapore more than a few times. "It's not the heat, it's the humidity". My own clothing was soaked because my body had grown up in an "In the heat you need to sweat. A lot." climate. The native Singaporeans stayed mostly dry because their bodies had learned that sweating doesn't help much, because the high humidity means little evaporation. Summer in Canada can be a lot hotter than Singapore, but most visiting Singaporeans don't know how to sweat "a lot", and so have more trouble here. Commented Mar 10, 2023 at 15:22

You can spray the inside or outside with polyurethane spray found at home improvement stores. It will make the shirt feel different but it will waterproof it long term

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