Under Armour built its name on a single idea: an athletic shirt that stays dry. Since 1996 the Baltimore-based brand has grown from that moisture-wicking compression shirt into a full performance wardrobe, and its best pieces are still some of the most useful things you can buy pre-owned. Technical fabrics are made to take hard use, so a well-kept HeatGear polo or ColdGear fleece often has years left in it. This guide covers the lines worth knowing, how to read Under Armour tags and fits, what to inspect before you buy, and how to keep performance fabric working the way it should.
The Story Behind Under Armour
Kevin Plank, a former special-teams captain on the University of Maryland football team, founded the company after getting frustrated that cotton T-shirts soaked through with sweat and stayed heavy. He set out to make a snug, synthetic shirt that pulled moisture away from the skin. That first idea, a fitted shirt worn close to the body, became the foundation of the brand and helped popularize the compression-style base layer across team sports and then everyday athletic wear.
Understanding that origin helps when you shop pre-owned. Under Armour designs for function first, so the details that matter are fabric, fit, and construction rather than seasonal trends.
The Three Lines to Know: HeatGear, ColdGear, and AllSeasonGear
Under Armour organizes much of its apparel around the temperature it is designed for. Knowing the system makes it easy to find the right piece.
HeatGear
Lightweight, breathable, and designed for warm conditions or high-output activity. HeatGear polos, tees, tanks, and leggings are the line most people encounter. The fabric is smooth and fast-drying, and it works as both a workout piece and a clean casual layer. HeatGear golf polos in particular have become a quiet staple of smart-casual dressing.
ColdGear
Designed for cooler weather, ColdGear typically has a brushed or fleece-like interior that traps warmth against the body while still moving moisture away. ColdGear base layers, fleece pants, and pullovers make excellent cold-weather layering pieces under a coat or on their own for a run or a walk. If you are building a winter wardrobe, our winter outerwear guide shows where a ColdGear layer fits.
AllSeasonGear
The middle ground, intended to be comfortable across a wide range of temperatures. It is a useful category for travel and for pieces you want to wear year-round.
Understanding Under Armour Fits
Under Armour labels the intended fit of many garments, and the difference is bigger than it sounds.
Compression: snug and stretchy, designed to sit like a second skin. It is meant to be worn tight, so do not size up to loosen it.
Fitted: close to the body without compressing it, an athletic cut that follows your shape.
Loose: a relaxed, roomier cut for comfort and airflow. Many HeatGear polos and tees are made this way.
Because the same brand uses all three, check the fit label on the tag or in the listing. A medium in loose fit and a medium in compression will wear very differently. As with any pre-owned shopping, rely on measurements as well as the size letter. Our size guide and sizing explainer can help you compare.
How to Inspect Pre-Owned Under Armour
Performance fabric ages differently from cotton or wool. Here is what to look for.
The fabric surface
Hold the garment to the light. The knit should look even and smooth. Heavy pilling, thinning at the underarms, or shiny worn patches in high-friction areas such as the inner thigh suggest the fabric has reached the end of its useful life.
Stretch and recovery
Gently stretch the fabric and let go. It should snap back. Fabric that stays stretched out or feels baggy at the waistband and cuffs has lost elasticity, which matters most for compression leggings and base layers.
Waistbands and seams
Check that elastic waistbands are firm and that flatlock seams lie flat without splitting. Look closely at the stitching around the crotch and underarms of leggings and shirts.
Logos and prints
Under Armour logos are usually heat-applied or embroidered. Light cracking on a printed logo is common with age and is mostly cosmetic. Peeling that exposes the fabric underneath is a sign of heavy wear.
Odor
Synthetic fibers can hold onto odor. A garment that smells clean after proper laundering is fine; a persistent smell that survives washing is worth skipping.
Spotting Authentic Under Armour
Athletic brands are copied less often than luxury labels, but it is still smart to check a few details. A genuine Under Armour piece will have clean, evenly stitched logos with crisp edges, a neatly printed interior tag showing size, fit type, and fabric content, and a style number and care instructions that read consistently. The interlocking UA logo should be symmetrical and well-defined. Sloppy lettering, misspelled tags, or fabric that feels rough and papery are reasons to be cautious. Our hand-inspection process is built around this kind of detail check.
How to Wear Under Armour Beyond the Gym
Performance pieces work well in everyday outfits when you style them with intent.
The polo. A HeatGear polo in a solid color pairs cleanly with chinos or tailored shorts for golf, travel, or a relaxed office. Choose neutral colors and keep the collar crisp.
The fleece pant. ColdGear sweatpants in navy, gray, or black look best with a plain knit or a simple jacket rather than a matching logo sweatshirt. The goal is a comfortable look that still seems considered.
The base layer. A fitted ColdGear top under a flannel, a fleece, or a coat adds warmth without bulk. It is one of the most efficient ways to extend a lighter jacket into colder weather.
For more ways to build a polished casual wardrobe from sportswear, see The Case for Pre-Owned Activewear, and for a look at another performance label, our guide to collecting pre-owned Lululemon.
How to Care for Under Armour Performance Fabric
Good care keeps moisture-wicking fabric performing.
Wash cold, inside out. This protects logos and reduces pilling.
Skip fabric softener. Softeners coat synthetic fibers and reduce their ability to wick moisture. Use a mild detergent instead.
Avoid high heat. Air dry or tumble on low. Heat degrades elastic fibers and can distort heat-applied prints.
Wash after wearing. Sweat and body oils break down synthetic fabric over time, so do not leave garments sitting in a hamper.
The general principles overlap with our guide to fleece care, which is useful for ColdGear pieces with a brushed interior.
Is Pre-Owned Under Armour Worth Buying?
For most shoppers, yes. Athletic apparel is built to withstand repeated washing and movement, so a lightly worn piece has plenty of life left. The value is strongest on items that see less friction, such as polos, jackets, and fleece layers, and somewhat lower on high-wear items like compression shorts where stretch fades quickly. Buying pre-owned also keeps technical fabric in use rather than adding to the demand for new synthetic production, which is a meaningful consideration given how resource-intensive performance textiles are to make. For a wider look at how to evaluate a pre-owned purchase, read our cost breakdown.
Frequently Asked Questions
What is the difference between HeatGear and ColdGear?
HeatGear is lightweight and breathable for warm conditions or intense activity, while ColdGear has a warmer, often brushed interior designed to hold heat in cooler weather.
Does Under Armour run small?
It depends on the fit type. Compression garments are meant to be snug, fitted styles follow the body closely, and loose styles run roomier. Check the fit label and compare measurements rather than relying on size alone.
How can I tell if Under Armour is real?
Look for symmetrical, cleanly applied logos, a well-printed interior tag with style number and care information, and consistent stitching. Rough fabric, misspelled labels, or uneven logos are warning signs.
Can you wear Under Armour casually?
Yes. Solid-color polos, fleece pants, and base layers work well in casual outfits when styled with simple, neutral pieces.
How do I keep Under Armour from pilling or smelling?
Wash it cold and inside out with a mild detergent, skip fabric softener, avoid high heat, and launder it soon after wearing.
Shop the Selection
If you are looking for performance pieces that have been hand-inspected and selected for condition, CENT'ANNII's sportswear collection includes Under Armour HeatGear and ColdGear pieces, such as these ColdGear fleece sweatpants, alongside other athletic labels. Each piece is one of a kind, so availability changes as items find new homes.
