Under Armour shirts have become a staple in athletic wardrobes and casual fashion alike, praised for their comfort and performance. Understanding what these shirts are made of reveals why they perform so well in various conditions. The primary focus centers on the proprietary fabrics developed by the company, which dictate the shirt's feel, fit, and functionality.
The Core Fabric: Polyester and Its Role
The dominant material in most Under Armour shirts is polyester. This synthetic fiber is chosen for its durability, resistance to shrinking, and, crucially, its ability to wick moisture away from the skin. Unlike cotton, which absorbs sweat and becomes heavy and clammy, polyester dries quickly and maintains its structure. This keeps the wearer dry and comfortable during intense workouts or long days out.
Moisture-Wicking Technology
The signature performance of Under Armour stems from its moisture-wicking technology. The polyester fibers are engineered with a specific cross-section that pulls sweat to the outer layer of the fabric. Once on the surface, the moisture evaporates rapidly, preventing the chilling effect of damp fabric against the skin. This technical aspect is the backbone of the brand's promise to keep athletes cool and dry.
Strategic Use of Nylon and Elastane While polyester is the workhorse, Under Armour blends other materials to enhance the shirt's characteristics. Nylon is often incorporated to add extra strength, abrasion resistance, and a softer hand feel. It also contributes to the overall lightweight nature of the garment, making it feel less like a protective layer and more like a second skin. For stretch and mobility, a small percentage of elastane (or spandex) is added to many styles. This allows the shirt to move with the body, providing a full range of motion without sacrificing support. The blend is carefully calculated to ensure the shirt retains its shape after repeated stretching and washing, maintaining a consistent fit over time. The ColdGear® Line: Focus on Insulation
While polyester is the workhorse, Under Armour blends other materials to enhance the shirt's characteristics. Nylon is often incorporated to add extra strength, abrasion resistance, and a softer hand feel. It also contributes to the overall lightweight nature of the garment, making it feel less like a protective layer and more like a second skin.
For stretch and mobility, a small percentage of elastane (or spandex) is added to many styles. This allows the shirt to move with the body, providing a full range of motion without sacrificing support. The blend is carefully calculated to ensure the shirt retains its shape after repeated stretching and washing, maintaining a consistent fit over time.
For colder environments, Under Armour utilizes its ColdGear® technology, which involves a different construction of the base fabric. These shirts often feature a brushed interior that feels soft and insulating against the skin. The fabric is designed to trap a thin layer of warm air close to the body while still managing sweat. The material is typically a knitted polyester-nylon blend that provides warmth without the bulk associated with traditional fleece.
HeatGear® and Lightweight Options
Conversely, HeatGear® shirts are designed for hot weather and high-intensity activities. These are made from an ultra-lightweight, sheer polyester mesh. The fabric is extremely breathable, allowing maximum airflow to cool the body. The focus here is on minimizing weight and maximizing ventilation, making the shirt ideal for running, hiking, or any activity that generates significant heat.
Sustainable Initiatives and Fabric Evolution
In response to growing environmental concerns, Under Armour has begun incorporating recycled materials into its supply chain. Some newer lines feature shirts made with recycled polyester, sourced from post-consumer waste like plastic bottles. This shift does not compromise the performance attributes of the fabric; it simply offers a more sustainable option for the environmentally conscious consumer without sacrificing the technical benefits of the synthetic fibers.
