Let's get straight to it — here's what actually matters on this one.

• Cotton absorbs moisture and breathes; polyester repels moisture and traps heat, making it feel warmer and clammier in humid conditions.
• Polyester resists wrinkles and holds color better over time, which is why it's common in travel and workwear despite comfort trade-offs.
• Cotton-poly blends (usually 60/40 or 65/35 cotton-dominant) aim to balance wrinkle resistance with breathability, a reasonable middle ground.
• For anything worn close to skin all day — undershirts, dress shirts — pure or majority cotton consistently outperforms polyester on comfort.

The fit-and-fabric-health takeaway: This comparison is really a breathability-versus-durability trade-off — and for all-day skin contact, breathability usually should win.

Next up: check out our guide on whether Egyptian cotton is worth the price.