Layering clothing is key to being comfortable in colder temperatures and baselayers are a critical part of layering especially if you are doing high intensity outdoor activities like hiking, running, or cycling. A quality baselayer balances breathability and warmth to provides you with thermal regulation to ensure you remain warm without overheating.  In this review, we’ll look at two women’s PEARL iZUMi Merino wool baselayers – the Merino Thermal Longsleeve Baselayer and the Merino Longsleeve Baselayer. These baselayers are part of the 2019 winter collection from PEARL iZUMi and are made with a blend of Merino fabric and recycled Repreve XS Polyester (made from recycled plastic water bottles). 

Despite the confusing products names, both PEARL iZUMi Merino wool baselayers are well constructed with tight seams and premium details. Although the thermal version is warmer we preferred the non-thermal as it felt more natural against the skin.

Both baselayers are offered in XS-XL sizes, with men’s variations and share a phantom color option. While both versions look similar and are made with 18.5 micron merino wool, the thermal version of the baselayer has a $20 higher retail price ($90.00 vs $110.00) and is advertised as PEARL iZUMi’s warmest baselayer with a density at 250 g/m2 (the non-thermal version does not have a published density). Despite the higher warmth of the thermal baselayer, it has a 35% blend of Merino wool compared to the non-thermal version’s higher 42% Merino wool content. Also, the non-thermal version is available in an Aquifer (Powder Blue/Pale Cyan) color.  

Merino Long Sleeve Baselayer
(Women’s )
Merino Thermal Long sleeve Baselayer
(Women’s)
CategoryClothing > BaselayerClothing > Base Layer
RatingDesign:  A
Size: B
Warmth: A
Value: B
Design:  A-
Size: B
Warmth: A
Value: B
Retail Price$90$110
Likes+ Odor resistant
+ Thumb Loops
+ Lightweight
+ Long back
+ Odor resistant
+ Thumb Loops
+ Heavier weight
+ Long back
Dislikes– Confusing Product Name
– Itchy in some areas when pulled taut (while riding).

– Confusing Product Name
– Feels Synthetic next to skin
– Higher price for the lower Merino wool content compared to the Non-thermal version.

Where to Buy (US) PEARL iZUMi PEARL iZUMi

UNBOXING

Both items came individually packed in environmentally friendly 100% recycled plastic bag and mailed in a carton like the other PEARL iZUMi items we’ve reviewed so far.

DESIGN

The baselayers have a clean and simple design with minimal logos on the front and below the neck. Both are long sleeve baselayers and have integrated thumb loops at the end of the sleeves which help when you’re layering. This is especially great for cycling as it closes the gap between your glove and the end of your sleeve where the cold air usually gets in. PEARL iZUMi states that they both have a “plated construction” with the polyester next to the skin and merino layer away from it. This is very apparent in the Merino Thermal Long sleeve Baselayer where you can actually see the two layers however the Merino Long Sleeve Baselayer seems like a single layer visually and is thinner in comparison. 

Pearl Izumi Merino Wool Baselayers - Comparison
Identical looking Merino Long Sleeve on the Left vs Merino Thermal Long Sleeve on the Right

Also, the Merino Thermal Long sleeve Baselayer has a matte finish exterior and a glossy polyester interior while the Merino Long Sleeve Baselayer has a shiny appearance on both surfaces. Both baselayers feature a longer rear panel for a better fit when cycling.

Pearl Izumi Merino Wool Baselayers - Thumbloops
Thumb loops ensures no gap between your gloves and jersey

SIZING

Based on our body measurements, the PEARL iZUMi sizing chart put us at a small. However, due to a shipping mistake both baselayers we received were medium. Even though we typically wear a small PEARL iZUMi cycling jersey (5’ 5”, 120lbs female), the medium size baselayers fit well. They are both form fitting and don’t prevent movement whether your riding the drops or hiking. However, during riding, the Merino Long Sleeve Baselayer felt a little itchy around the inside of the elbow and mid-back (areas where its pulled taut).

Pearl Izumi Merino Baselayer fit
Fit

WARMTH

We tried them for hiking as well as higher intensity activity like cycling. Hiking in 45F with just the Merino Long Sleeve Baselayer and a puffy down jacket kept us plenty warm without needing a mid-layer. Thanks to the Merino wool content, even at warmer temperatures the baselayers provided an excellent balance between warmth and breathability. Additionally, the baselayers were stink-free allowing us to wear them post workout.

For cycling, we found that the Merino Thermal Long sleeve Baselayer was ideal for colder days, but became uncomfortably warm if the temperature exceeded 55F. We found the thermal baselayer noticeably warmer than the non-thermal version. However, with this baselayer, you can feel the polyester layer next to your skin which is not a nice feeling especially if you’re sensitive to synthetic fibers.

Pearl Izumi Merino Thermal Longsleeve Baselayer - Construction
Two distinct layers in the Merino Thermal Longsleeve Baselayer

VALUE

Despite the confusing products names, both baselayers are well constructed with tight seams and premium details. Although the thermal version is warmer we preferred the non-thermal as it felt more natural against the skin. Unlike other baselayers on the market, you can’t wear these as a standalone top as the plastic vendor tag that’s sewn on the outside is non-removable without destroying the seams. While we appreciated the quality and warmth of the baselayers, at the retail price there are higher Merino wool content baselayers available.

Disclaimer: The product for this review was provided by PEARL iZUMi. The views expressed on this website are solely those of the authors and are here to help people make an informed choice before a purchase. The authors or the blog itself does not get any monetary compensation from the product manufacturer or third-party websites/vendor links that are posted here.

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