Most men train in a giveaway t-shirt and an old pair of football shorts. It works right up until the first serious session where the soaked t-shirt starts weighing close to 1 kg, or the inner seam of the shorts splits in a deep squat. The wrong choice ruins sessions; the right one disappears into the background, which is exactly the point.
In Portugal, gyms are the second most common place for physical activity (behind commuting between home and work), and gym activities are the number one physical activity reported by adult men, ahead of running and walking (IPDJ, 2024). People who train seriously are the majority, not the exception, and the right gear is part of the job.
This guide covers the four essential pieces (technical t-shirt, shorts, technical briefs, compression) with its own criteria for each one, follows up with fabrics, segmentation by training type, and ends with the top PT 2026 picks (Decathlon, H&M, Nike, adidas, Gymshark, Lululemon, Vuori). For each piece that has its own guide (shorts, trainers), I point to the full detail.
The four essentials and how to pick each one
Four pieces sort 90% of your sessions: technical t-shirt, shorts with elastane, technical briefs, stable trainers. Compression and specialist socks come later. Trainers have a dedicated guide (see the men's gym shoes guide); the focus here is on clothing.
1. Technical t-shirt (the piece you'll notice the most)
The technical t-shirt is the piece that takes on the most sweat during a session. Cotton absorbs up to 30 times its dry weight in sweat, turns heavy, cools the body between sets, and takes hours to dry. Polyester or nylon wicks moisture out, stays light, and dries in 20 to 30 minutes. For any regular gym-goer, switching from cotton to technical is the upgrade you'll feel the most, and it costs very little.
The three criteria for choosing:
Fabric: polyester or nylon plus 5 to 15% elastane. Moisture-wicking (anti-sweat) and antibacterial finishes are worth the small premium, especially on t-shirts worn several times a week.
Fit: snug across the chest and shoulders (shows the work but doesn't restrict), looser around the abdomen (free movement). Avoid a t-shirt two sizes below your real one (the exaggerated "muscle fit") that ends up looking ridiculous halfway through the session once the pump fades.
Sleeves: short for general use; sleeveless (tank top) for heavy lifting with squats and bench press (shoulder mobility); long sleeves for cold air-conditioned spaces or to head straight from the gym to the street.
2. Shorts (5, 7 or 9 inches depending on the training)
Quick summary (full detail in the shorts guide):
5 inches (about 13 cm): HIIT, cardio, calisthenics. Maximum mobility.
7 inches (about 18 cm): general use. Balance between coverage and movement. The default recommendation.
9 inches (about 23 cm): heavy weight training, powerlifting. Coverage approaches the knee.
Fabric: polyester with at least 8% elastane. Without elastane it fails at extreme mobility (deep squat).
Linerless or with a liner? Linerless (no inner brief) is the 2026 trend and gives you versatility (the same shorts work from the gym to the cafe); it requires proper technical briefs underneath, as we'll see next. With a liner replaces the brief and saves on laundry; some find it chafes on long sessions.
For the full detail (PT prices, pros and cons of seven models from Nike, adidas, Lululemon, Vuori, Decathlon and Gymshark), see the complete men's gym shorts guide.
3. Technical briefs (essential if you wear linerless shorts)
Damp cotton in the groin area causes chafing, irritation, and on long sessions can lead to superficial infections. A technical brief isn't a luxury; it's basic hygiene for anyone training three or more times a week. The cost is low (from €12 up), the impact on the quality of the session is high.
Two valid technical materials:
Polyamide with elastane: dries fast, compresses without pinching, antimicrobial. Most technical brands (Nike, Saxx, Under Armour) use this blend.
Merino: natural wool, controls odour better than synthetics, more expensive and takes a little longer to dry. Brands like Icebreaker, Smartwool, Decathlon Forclaz and Quechua Merino.
Models to avoid: classic cotton, even if the label says "100% premium cotton". For the gym it simply doesn't work; moisture stays trapped and chafing is unavoidable.
PT picks 2026:
Decathlon Quechua merino: €12 to €20
Nike Pro Boxer Brief: €25
Saxx Quest: €30 to €35
Under Armour Performance: €18 to €25
4. Compression (optional, but useful in specific cases)
Compression is a tight-fitting piece (sleeveless top, short sleeve, long sleeve, or leggings) made of polyamide with 15 to 25% elastane. It applies even pressure to the muscle. It isn't a mandatory piece; it makes sense in specific cases:
Cold air-conditioned spaces: a compression top under your t-shirt keeps the torso warm without extra weight, a lighter alternative to a jacket.
Recovery: wearing compression on the legs for one to two hours after a heavy leg session speeds up venous return and reduces delayed onset muscle soreness (DOMS).
Very intense sessions: compression reduces "parasitic movement" of the muscle tissue during jumps and changes of direction, which many report as less accumulated fatigue across the session.
When it does NOT make sense: as a single layer in summer (too hot), for moderate traditional weight training (marginal gain doesn't justify the price), or if you've never used it and want to "see if it's like they say" without trying it (buy a single piece before investing in the full kit).
PT picks 2026:
Decathlon Kalenji compression: €12 to €20
Under Armour HeatGear: €25 to €35
Nike Pro Compression: €35 to €45
Fabrics: what to look for and what to avoid
The label says more than the model name. What matters:
Polyester: the standard. Breathes well, dries fast, durable. 80 to 90% of technical pieces use it. There's no reason to look for anything else in budget and mid-range items.
Nylon: softer than polyester, common in premium pieces and in compression gear. More expensive, easier to stain.
Elastane: 5 to 15% in t-shirts and shorts; 15 to 25% in compression pieces. Without it the piece doesn't stretch and tears on the first session of extreme mobility.
Merino: for cold air-conditioned spaces (outdoor winter) or for technical briefs where odour control matters. Expensive but it pays off in heavy-use pieces.
Cotton: avoid for any serious training. It absorbs sweat, turns heavy, cools the body between sets, and takes hours to dry. The only valid context: vintage t-shirts for wear outside the gym.
Finishes to look for on labels: moisture-wicking (anti-sweat, pushes moisture to the outside), four-way stretch (stretches in all directions), antimicrobial (anti-odour after several washes, important on t-shirts and technical briefs worn several times a week).
Kit by training type (quick segmentation)
The choice depends more on your dominant training type than on your level. Reference table:
Training
T-shirt
Shorts
Compression
Yoga, mobility, stretching
Loose short sleeve, polyester or bamboo
7 to 9 inches, no liner
Not needed
Light to moderate weight training
Snug on the chest, short sleeve or sleeveless
7 inches, with or without liner
Optional
Indoor cycling / spinning
Snug, anti-odour (you train with chest near the handlebars)
Proper cycling shorts (padded) or capri
Yes, leggings optional
HIIT, functional training
Snug, short sleeve, sleeveless even better
5 inches, linerless
Yes to reduce parasitic movement
Powerlifting / heavy strength
Sleeveless or snug technical cotton
9 inches with liner, or linerless plus briefs
Compression knee sleeves yes for squats
The table is a starting point; fine adjustments come with experience. Anyone combining weight training three times a week with one weekend run does well to keep two pairs of shorts (7 inches for the lifting, 5 inches for the run) and dedicated t-shirts.
Where to buy in Portugal (with 2026 prices)
The Portuguese 2026 offer covers every price tier. Quick map:
Decathlon: the Domyos line is the main one. T-shirts €4 to €12, shorts €7 to €15, Quechua technical briefs €12 to €20, Kalenji compression €12 to €20. A complete starter kit for €40 to €60. Unbeatable on price to get going.
H&M Move: H&M's in-house brand launched in 2023, sits between Decathlon and Nike. T-shirts €8 to €15, shorts €12 to €25. More "fashion-fitness" than technical.
Nike Portugal: classic Dri-FIT, t-shirts €27.99, shorts €37.99. Quality-to-price sweet spot for three or more sessions a week.
adidas Portugal: the European alternative to Nike, same price tier, design slightly more understated and fewer visible logos.
Sport Zone: multi-brand retailer (Nike, adidas, Puma, Reebok, Under Armour). Good for end-of-season discounts and for comparing several brands in one place.
Under Armour Portugal: compression specialist (HeatGear range), tops €25 to €45. Pays off more for cardio and HIIT than for classic weight training.
Gymshark: the Apex and Crest lines are the best known; t-shirts €25 to €35, shorts €30 to €40. Dominant aesthetic on Instagram and popular with younger lifters; technically solid but the style sells more than the performance.
Lululemon: imported premium. Metal Vent Tech t-shirt €75, shorts €60 to €90. Worth it for anyone training four or more times a week who prioritises a premium feel.
Vuori: premium alternative to Lululemon, more "casual-fit". Strato Tech €60. For people going from the gym straight to brunch without changing.
Gym clothing is technical kit, not bedsheets. Treated like normal laundry, it lasts half as long. Four simple rules:
Wash inside a mesh bag. Friction in the machine against zips, hooks and Velcro destroys stretch fabric. A laundry bag (€3 to €5 at any Decathlon or H&M) cuts 80% of the problem. Especially worthwhile for compression and technical briefs.
Cold water, short cycle. Temperatures above 30 degrees degrade elastane (the piece loses its stretch). Softener clogs moisture-wicking fabrics and leaves them smelling of sweat even after washing. A neutral liquid detergent works better than powder.
Air dry, away from sunlight. A tumble dryer on high heat is the worst enemy of any piece with elastane. Direct sun fades dark colours (black turns grey in a few months).
Replace before visible failure. Technical t-shirts used three to four times a week last 12 to 24 months. Technical briefs last 6 to 12 months (the elastic band fails first). Compression lasts around 12 months (it loses compression before the fabric visibly tears). When a piece starts to feel "too loose" at its tightest fit or smells of sweat even after washing, it's time to swap.
Four common buying mistakes (and how to avoid them)
The technical choice can be perfect and the purchase still go wrong for four predictable reasons:
Mistake 1: t-shirt two sizes too small. Cuts shoulder movement and dents self-esteem once the session's pump fades. Snug across the chest, yes, stretched like a second skin, no. The quick test: if raising your arms makes the hem climb above your belly button, it's too tight.
Mistake 2: old football shorts. Polyester without elastane that tears at extreme mobility, an elastic waist that slips during squats. Works if you only use the treadmill; fails in any session involving deep hip flexion or deadlifts. Detail and alternatives in the shorts guide.
Mistake 3: skipping technical briefs. Sticking with cotton briefs under linerless shorts is the number one cause of chafing and bad smells. Investing €20 in two technical briefs solves a problem nobody wants. For people just starting out, the beginner gym workout plan already assumes a base technical kit.
Mistake 4: one premium brand all at once. Lululemon and Vuori are expensive (€75 for a t-shirt). For someone training three times a week, one premium t-shirt with the rest from Decathlon plus Nike is enough; spending €400 in one go before knowing what works is predictable waste.
Frequently Asked Questions
A technical polyester t-shirt (not cotton), shorts with elastane (5 inches for HIIT, 7 for general use, 9 for heavy lifting), technical briefs if you wear linerless shorts, and trainers with a stable sole. Avoid heavy cotton and cushioned running trainers.
Polyester with elastane for any serious workout. Cotton absorbs sweat (up to 30 times its dry weight), turns heavy, cools the body between sets, and takes hours to dry. The only valid use for cotton is outside the gym.
For cold air-conditioned spaces, recovery after heavy leg sessions, or HIIT and crossfit, yes. For moderate traditional weight training, the gain is marginal and the price doesn't justify it. Start with a single piece (top or leggings) before investing in the full kit.
If you wear linerless shorts and train three or more times a week, yes. Damp cotton in the groin causes chafing and bad smells. €20 on two pairs of technical briefs (Decathlon Quechua merino or Nike Pro) sorts the problem without a big outlay.
For indoor running (treadmill), yes, the same pieces work. For regular outdoor running, it's worth considering lighter shorts, a t-shirt with a pocket, and dedicated trainers. For road cycling, padded cycling shorts are separate from any gym kit.
For three sessions a week, a base kit of €80 to €130 (three t-shirts, two pairs of shorts, three technical briefs, and one compression piece if useful) covers the year. Above €250 you're in premium territory (Lululemon, Vuori) with a real but marginal difference.
Technical t-shirts used three to four times a week last 12 to 24 months. Shorts with elastane last 12 to 24 months. Technical briefs last 6 to 12 months (the elastic band fails first). Compression lasts about 12 months (it loses compression before the fabric visibly fails).
In a mesh bag (stops abrasion), cold water at 30 degrees, no fabric softener (it clogs moisture-wicking fabrics), no tumble dryer (high heat destroys elastane). Air dry away from direct sunlight.
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TLDR: Key Points
A technical polyester t-shirt with elastane (not cotton) is the piece you'll notice the most. Cotton turns heavy and cools the body once the effort eases off.
Shorts: 5 inches for HIIT and cardio, 7 inches for general use, 9 inches for heavy lifting. Always with elastane.
Technical briefs (merino or polyamide with elastane) are essential if you wear linerless shorts. Damp cotton in the groin area is a recipe for chafing.
Compression (a fitted top worn underneath) makes sense in cold air-conditioned spaces or for muscle recovery. It's a personal call, not a must.
In Portugal, Decathlon Domyos covers the full budget kit (€40 to €60); Nike and adidas are the sweet spot at €80 to €130; Lululemon, Vuori and Gymshark are the premium imports.
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