There are tons of great options when it comes to trail running shirts, but when the heat of the summer sets in, a lightweight and breathable shirt is key. The Mammut Aenergy FL Tee is incredibly-airy and comfortable on the trails and has been my go-to for morning trail running and hiking.
Mammut Aenergy FL Short Sleeve Shirt Features:
- Made of 100% recycled polyester
- Optimized mesh ventilation zones on back and under arms
- Offset, smooth merrow-stitch seams
- Treated with HeiQ Fresh FFL – a bio-based treatment to reduce odors
- Quick-drying fabric
- Reflective elements
- Athletic cut
- Weight: 96 grams
- MSRP: $69
Ideal running shirt for summer days
From the Wasatch to the Pacific Northwest, the Mammut Aenergy FL running shirt has been a great choice. When it first arrived and I slipped it on, it just felt right. Listed as an “athletic cut,” I decided on a size large and that was a great choice for all-around comfort. Sometimes it’s nice to have a loose fit option as most of my summer running shirts are more form-fitting. Honestly, I’d say it drapes perfectly and efficiently for all sorts of trail adventures. The added length always maintains coverage and does great with my middle-aged dad bod.
Originally available in a whopping 10 colors, the bright white has been extra-awesome for the warmest days. Without any added thermal heating, I’ve always stayed extra cool. At running speeds, it feels airy and light — with tons of airflow permeating through the fabric. While hiking, I don’t sweat as much, but the fabric still does an awesome job of dissipating perspiration and keeping me cool. The cooling factor of the Aenergy FL is excellent.
With lightweight mesh fabric, durability is always a concern, but after a season of use, it shows no signs of wear — even though I had more than my fair share of encounters with Utah’s scratch scrub oak bushes. It’s been tossed in with all our white loads of laundry and dried without any undue wear.
The front panel and top of shoulders has a slightly more tight-knit fabric and the rear/underarms is more porous. That combo is incredible at dissipating moisture without ever feeling saturated and soggy. Even in the middle of a long run, the Aenergy FL drapes well without any drooping. With a minimalist collar, this shirt stays out of the way and the design looks great on and off the trail. I appreciate the minimal branding and the classic mammoth icon on the left sleeve keeps things traditional.
I’ve worn this shirt for both hiking and trail running. And, I’ve also used it in the dry Utah heat and the humid Seattle air. Under both conditions, I’ve yet to overwhelm the fabric. After finishing up a trail run, the shirt only takes a few minutes to dry. Unfortunately (even though it’s treated), odor protection is pretty poor. I can wear it twice, but that’s about it — a far cry from something like the Ibex Paradox Short Sleeve that stays stink-free for days.
Fit: I’m 5’11” and 175 lbs., wearing the size large.
Buy Now: Visit Mammut.com
The Bottom Line
The Mammut Aenergy FL Short Sleeve is a lightweight, breathable running shirt built for peak summer adventures. Its airy mesh panels keep airflow high and moisture moving, while the athletic cut drapes well without clinging. Quick-drying and durable beyond expectations, it handles both dry Utah heat and humid coastal trails with ease. Odor control could be better, but for pure cooling performance, it’s an excellent choice for hot-weather running and hiking.
The Good:
- Supremely-breathable
- Fells comfortable next-to-skin
- Non-clinging fabric makes it easy to take off
- Minimalist seams go unnoticed
- Added hem length for coverage
- Mammut makes it easy to pull off the long tags inside the shirt
The Bad:
- Not great at keeping body odors away
- The collar tag isn't bad, but I always appreciate no-tag designs
- Comfort
- Fit
- Durability
- Breathability
