Made for women who prefer the comfort and breathability of natural fibers, the Runyon Cottontrails™ 100% Cotton Muscle Tee is a versatile sleeveless shirt for running, hiking, gym workouts, strength training, yoga, travel, and everyday wear. Designed with unisex sizing, this lightweight cotton muscle tee features extended shoulder coverage and a relaxed athletic silhouette that moves comfortably from workouts to the outdoors.

Crafted from 100% cotton grown in the USA, each muscle tee is garment washed and pre-shrunk for a soft, broken-in feel from day one. The breathable natural cotton fabric makes this an easy alternative to synthetic performance apparel for women looking for a natural fiber workout shirt for lifting at the gym, heading out for a morning run, hiking the trails, or simply wearing around town.

A curved bottom hem adds a clean, flattering finish, while minimal branding keeps the look simple and versatile. Designed, engineered, and field-tested by endurance athletes and cut and sewn in Los Angeles, California.

This style is Unisex. For women's sizing, XXS is comparable to a Women's Small, XS to a Women's Medium, and S to a Women's Large.

Cottontrails™ Collection

Launched on May 1, 2026, the Cottontrails™ Collection is our premium line of 100% cotton apparel crafted from USA-grown cotton and proudly Made in Los Angeles, California. Every garment is individually handcrafted, pre-washed, and pre-shrunk for exceptional comfort, durability, and a consistent fit from day one. Designed for adventure and everyday movement, our breathable natural fiber clothing is made for hiking, camping, travel, training, fitness, and everyday wear.

Designed, engineered, and field-tested by endurance athletes, the Cottontrails™ Collection combines timeless style with the natural comfort of cotton. Whether you're hitting the trail, working out at the gym, exploring the outdoors, or looking for comfortable everyday apparel, Cottontrails™ delivers breathable natural fibers, freedom of movement, and American-made quality. For those searching for Made in USA cotton apparel, natural fiber activewear, 100% cotton workout clothing, or durable outdoor essentials, Cottontrails™ was built for wherever the day takes you.