Forclaz MT500 Merino Wool Long-Sleeve Shirt Review
The Forclaz MT500 is a budget-friendly 190gsm merino long-sleeve base layer that punches above its price point for spring/autumn trekking and multi-day hikes.
Overview
The Forclaz MT500 is Decathlon’s mid-weight merino long-sleeve base layer, aimed squarely at trekkers and thru-hikers who want legitimate wool performance without paying Icebreaker or Smartwool prices. The shirt uses a merino wool/polyamide construction where the wool fiber is surrounded by polyamide yarn for added protection — a design that nudges durability up without leaning fully into synthetic territory. At 222g in a size L, it’s a reasonable trail weight for a 190gsm merino shirt, and the 86/10/4 merino-polyamide-spandex blend is the same formula Forclaz uses across its MT500 base layer line.
Key Specs
| Spec | Value |
|---|---|
| Weight | 222g (size L) |
| Fabric Weight | 190 g/m² |
| Material | 86% merino wool, 10% polyamide, 4% spandex |
| Merino Fineness | 18.5 microns |
| Sizes | S – 3XL (men’s) |
| Care | Machine wash 30°C, flat dry — no tumble drying |
Performance
Thermal regulation and seasonal fit
The MT500 is built around a single 190 g/m² fabric weight, which provides warmth in cold weather but is too heavy to use solo in summer — it’s best suited for spring and autumn activities or as an evening layer at camp. In winter it reaches its limits below around 10°C unless used as a base layer under high-insulation mid and outer layers. So this isn’t a three-season shirt in the way a 150gsm merino can be — it’s a cool-weather workhorse or a reliable layering piece. If you’re heading into the mountains in July, you’d want the lighter version; for October trekking or alpine shoulders, this weight makes a lot of sense.
Moisture management and warmth-when-wet
When you’re working hard and sweating, the merino wool traps insulating warm air and can absorb up to 35% of its weight in moisture without making you feel damp — a significant advantage in cool weather. When wet, you don’t feel cold, and the shirt dries quickly — useful on long treks where you might wash it mid-route and need it back on the same day. In Decathlon’s own climate-chamber testing, wool maintained a more consistent body temperature after heavy sweating, while synthetic fabrics cooled down faster — reducing that unpleasant chilling effect post-exertion.
Odor control
In terms of sweat, the MT500 does a good job limiting odors and doesn’t saturate quickly — though eventually it does, which reviewers attribute to the synthetic fiber content. That’s a fair and honest finding. Pure merino holds off longer; the polyamide blend trades some odor resistance for durability and lower cost. For a two- to four-day stint between washes, you’ll be fine. Any longer and you might catch a whiff.
Fit and feel
Upon first wear, the MT500 is comfortable with a soft feel and doesn’t itch — which isn’t always guaranteed with merino — and the fit is snug, hugging the skin and following movement. It covers the lower back well and stays put under a backpack, with long sleeves that reach to the hands and seams that cause no irritation. The shirt is designed with a fitted cut for enhanced moisture transfer; if you prefer a looser fit, size up one.
Softness vs. premium merino
The 18.5-micron fiber is genuinely fine — those ultra-thin fibers don’t itch, unlike traditional wool garments. That said, if you’re coming from Icebreaker, manage expectations. In a head-to-head comparison, Decathlon’s merino is objectively lesser — not as soft, slightly more abrasive, with a looser weave and lower overall merino quality. It’s not as soft or comfortable as Icebreaker, Arc’teryx, or Devold, but it’s quite durable and arguably beats out Smartwool — and the price is a real differentiator. That’s a pretty solid competitive position for a shirt that likely costs a third of what an Icebreaker 200 Oasis would set you back.
Durability
In field testing, no premature wear was observed, though merino wool is more fragile than cotton or synthetics and requires care over time. Some pilling may appear over time, which is common with merino but doesn’t affect the functional quality of the wool. The polyamide wrapping around the wool fibers is the key durability feature here — the blend results in a more durable shirt, slightly reduced weight, and lower manufacturing cost, which flows through to a lower retail price.
Sustainability note
The merino wool used by Forclaz is produced in South Africa on farms that respect animal welfare. However, the shirts themselves are manufactured in Asia — China, Vietnam, and similar countries. It’s a step in the right direction on the sourcing side, but the supply chain is long.
Pros & Cons
Pros
- Genuine 18.5-micron merino — non-itchy, confirmed in independent testing
- Strong thermal regulation and warmth-when-wet performance
- Odor control ISO-tested; holds up well for multi-day use
- Snug fit stays in place under a pack without riding up
- 4% spandex provides natural stretch and unrestricted movement
- Polyamide-wrapped fibers add meaningful abrasion resistance
- Machine washable at 30°C — easier care than some wool garments
- Substantially cheaper than Icebreaker/Smartwool equivalents
Cons
- 190gsm is a narrow sweet spot — too warm for summer, too thin for hard winter without layers
- Noticeably less soft and refined than premium merino brands (Icebreaker, Devold)
- Synthetic content means odor eventually breaks through on longer wear stretches
- Pilling is possible over time
- Strict care requirements: flat dry only, no tumble drying whatsoever
- Color selection is modest and leans muted — won’t appeal to anyone wanting a pop of color on trail
Who Should Buy This
This shirt is made for the budget-conscious trekker or thru-hiker who wants a real merino base layer — not a merino-blend-in-name-only — without spending over $100 on a single shirt. It’s particularly well-suited to spring and autumn three-season hikers, anyone doing multi-day routes where odor control and quick-dry matter, and travelers who need a versatile shirt that layers under a fleece just as easily as it stands alone at camp. Thanks to its multi-day odor resistance, this merino shirt can be worn for several days in a row, letting you carry less clothing and lighten your pack. If you’re deep into ultralight gram-counting and expect premium softness, you’ll want to spend more. Everyone else: this shirt is hard to argue with.
Verdict
The Forclaz MT500 does what it promises and doesn’t pretend to be more than it is — a solid, practical, well-priced merino base layer for cool-weather hiking. It’s a well-cut, comfortable, warm shirt that works solo or as a base layer in mid-season mountain conditions, with excellent value for the use of merino wool. It’s not the softest shirt in the drawer, and the 190gsm weight narrows its seasonal range, but for the price point, it’s one of the best entries into merino layering available. Rating: 7.5/10.