Forclaz MT500 Merino Long-Sleeve Review
Decathlon's 190 g/m² merino long-sleeve base layer trades a little softness and wool purity for durability and a low price. Here is how it performs on trail.
Overview
The Forclaz MT500 is Decathlon’s mid-weight merino long-sleeve, built for trekkers who want wool’s warmth and odor resistance without paying Icebreaker or Smartwool prices. It uses 18.5-micron merino spun around a polyamide filament, which makes it tougher than a pure-wool shirt and cheaper to produce. The trade-off is a single, fairly heavy fabric weight that suits cool weather better than summer.
Key Specs
| Spec | Detail |
|---|---|
| Weight | 222 g (size L) |
| Fabric weight | 190 g/m² |
| Fiber | Merino wool (about 86%) wrapped around polyamide filament |
| Merino fineness | 18.5 microns |
| Odor testing | ISO 17299-3 |
| Fit | Snug, body-hugging |
| Sizes | S–3XL (men’s) |
| Care | Machine wash at 30°C, dry flat |
Would the Forclaz MT500 100% Merino Wool Long-sleeve Shirt earn its spot in your pack?
Add the Decathlon Forclaz MT500 100% Merino Wool Long-sleeve Shirt to your Gear Closet and see exactly what it does to your base weight, then start packing for your next trip.
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Performance
Comfort. At 18.5 microns, the wool sits near the fineness where most people stop noticing itch. Testers at French outlet Test 4 Outside found it soft on first wear and free of the prickle that sometimes comes with merino. It isn’t the softest shirt in the drawer, though. Owners who have worn premium merino will notice the difference, and the polyamide wrap gives the fabric a slightly more technical hand.
Warmth and moisture. The 190 g/m² fabric is on the thick side for a base layer. Decathlon’s own chamber testing found that wool holds body temperature steadier than synthetics after hard effort, and that the post-sweat chill is reduced. Test 4 Outside’s winter trekking and climbing test matched this. The shirt stayed warm in the cold, breathed acceptably when it warmed up, and didn’t feel clammy when damp. It also dried quickly, which let testers wash it mid-trek and put it back on without a long wait.
Odor. Decathlon backs the shirt’s odor control with ISO 17299-3 testing. In the field, owners report wearing it for days with little smell. One verified buyer wore it for two straight days with no odor at all. The Test 4 Outside reviewers noted that it resists odor well but does eventually saturate, probably because of the synthetic content. That is still enough to support the usual two-shirt rotation on a multi-day trek.
Fit and durability. The cut is close to the body. It stays in place under a pack, covers the lower back, and doesn’t sag when worn alone. It rides up a little, but the stretch makes it easy to pull back down. The polyamide wrap is the durability story: abrasion from pack straps and hipbelts is the usual killer of merino, and this construction is meant to resist it. It is also machine washable at 30°C, which is easier than many wool garments. Dry it flat, not in a tumble dryer.
Seasonal range. Because it comes in one weight, 190 g/m² narrows the shirt’s range. It works well in spring and autumn, in mountain conditions, and as a camp layer under a fleece or puffy. In midsummer heat, thru-hikers will want something closer to 150 g/m². At about 222 g in a size L, it is reasonable for its fabric weight but not a gram-saver. Merino of this thickness always weighs more than a comparable synthetic.
Pros & Cons
Pros
- 18.5-micron merino that doesn’t itch for most wearers
- Stays warm when damp, and dries quickly for merino
- Odor resistance backed by ISO 17299-3 testing
- Polyamide-wrapped yarn improves abrasion resistance
- Snug cut stays put under a pack and covers the lower back
- Machine washable at 30°C
- Priced well below name-brand merino
Cons
- Not 100% wool: the blend gives up some softness and some odor resistance
- 190 g/m² is too warm for summer hiking
- 222 g (size L) is heavier than ultralight synthetic or 150 g/m² merino options
- Tends to ride up slightly
- Must be dried flat
Who Should Buy This
This is a shirt for budget-minded trekkers and thru-hikers who want a durable merino base layer for shoulder-season trips, mountain routes and cold camps. It suits anyone who wants to carry one or two shirts for a week or more. Gram-counters, summer hikers and anyone who expects premium softness should look elsewhere. A lighter 150 g/m² merino or a synthetic tee fits those needs better.
Verdict
The MT500 does what it claims and doesn’t pretend to be more. It is a warm, durable, odor-resistant merino shirt at a price that undercuts the big names by a wide margin. For cool-weather hiking and layering, it is one of the better entry points into merino. Summer use and ultralight weight targets are the main reasons to spend more or choose differently.