Does this crew neck run true to size?

The 18-Hour Jersey Crew Neck has a deliberately slim, fitted cut. If you have a broader chest or wider midsection, you should size up one size for comfort. Many customers with athletic or larger builds find they need to go up. If you prefer a closer fit or have a slim build, your regular size will work.

What's the fabric like? Will it be too hot to wear under other shirts?

The 18-Hour Jersey is a lightweight, breathable cotton blend that won't overheat you under dress shirts or layers. Customers consistently describe it as light and breathable, and many wear it both as an undershirt and as a standalone workout tee, so it performs in multiple conditions.

Will the collar roll or stretch out over time?

No. The crew neck collar holds its shape through regular wear and washing. Customers report the fit and structure remain consistent after multiple wash-and-dry cycles. This is part of what makes it reliable as a daily undershirt.

Can I use this as a workout shirt, or is it only for under clothes?

You can absolutely wear it as a workout tee. The side seams are positioned to prevent underarm chafing during movement, and the breathable 18-Hour Jersey fabric works well for running and active use. Many customers rotate these between workouts and everyday wear.

Is this machine washable and dryer safe?

Yes. The 18-Hour Jersey holds up well in the washer and dryer without shrinking or losing its shape. Customers report getting multiple wears and washes from these undershirts while the fabric and fit remain intact.

Mack Weldon 18-Hour Jersey Crew Neck Undershirt

IN CM

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Micro-Brushed French terry

So you get an ultra-soft feel (that doesn’t fade in the wash).

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Streamlined Fit

So you can wear them anywhere.

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Perfect Stretch + Recovery

So they’re always comfortable, but never saggy.

close up of ribbed cuff on the ankle of ACE navy blue sweatpant

Back-Ribbed Ankle Cuffs

So they maintain their shape at the hem.

18-Hour Jersey

Our signature blend of cotton, modal, and stretch, tailor-made for exceptionally comfortable underwear and undershirts.

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Shop All 18-Hour