Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&
Base Layer - Thermoregulator Base Layer - Men&

Men's Thermoregulator SS Base Layer

111 reviews
Regular price$74.00
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OVERVIEW: The Thermoregulator has been designed to provide a stretchy form fit and optimal moisture transfer and heat regulation during cool or cold weather rides. The unique construction using Dryarn®, not only the lightest textile fabric in the world but exceptionally efficient at pushing moisture away from the skin, means the Thermoregulator Base Layer simultaneously keeps you warm and dry without feeling bulky or heavy. 

Peloton Magazine"Pactimo, based in the home of schizophrenic weather (Colorado), designed the Thermoregulator to be the perfect foundation of any cold-weather wardrobe. It absorbs less moisture, breathes better and transfers more moisture than other fabrics. What's truly amazing is that in cold weather it works like a thermostat, transferring heat and moisture but retaining heat while still transferring moisture when you need warmth. It's comfortable and cozy without being bulky." 

FABRIC & CONSTRUCTION: Dryarn® is a high-performance microfibre providing top levels of physical comfort even in the presence of frequent and unexpected changes in climate conditions and variations in the intensity of physical effort. Dryarn’s low coefficient of heat dissipation, prevents any unwanted loss of body heat and at the same time enables the rapid dissipation of excess heat via evaporation of perspiration. This is facilitated through a capillary action where perspiration is collected and carried along the fibre to the surface where it can evaporate. The exceptional stretchiness and comfort of this garment is achieved with XLA® Fibers.


  • Dryarn® Polypropylene 93% and Elasten XLA® 7% 
  • Pactimo TotalFit™ design for excellent anatomical fit 
  • 30° - 60° F

Ideal pairing is with any of our cool or cold weather garments such as the Alpine Thermal RT Jersey or with a regular jersey and the Cascade RT Jacket. Layering in cold weather cold helps maintain core body as warm air is trapped in the various layers of moisture-wicking clothing. 

Have questions about sizing, fit or garment usage?

Don't hesitate to contact us.

Yosh  Melissa  Ryan

We are here to help and answer all your questions!


Or, send us an email and we will get back to you as soon as possible.

Fit Guide


Items designed to provide a traditional performance fit.


Items in this category have been designed to provide an aerodynamic form fit.

Second Skin Fit


Items in this category have been designed to provide an ultra form fit.

Fit Videos


Size Charts

Custom cycling clothing size chart example - man
Pactimo Cycling Clothing Size Chart
Custom cycling clothing size chart example - woman

Kid's Cycling Clothing Size Chart

PLEASE NOTE: Not all garments are available in every size listed on size charts.

Arm, Knee and Leg Warmer Sizes

Shoe Cover Size Chart

Custom cycling sock size chart

Cycling Glove Size Chart

Measuring Tips 


Using a soft measuring tape, bring the tape across your back under each arm, around the front. For women, measure the widest point of the bust. For men, measure around the largest part of your chest.


Bend to one side to find natural indentation in torso. This is your natural waist. Run tape around waistline, keeping tape parallel with floor. 


Stand on a level surface with feet together. Measure around fullest part of hips and bottom (approximately 7" - 9" below waistline), keeping tape parallel with floor.



Typically delivers in 3-5 business days
(Standard Shipping Option)


USPS Priority

1-3 business days.

USPS Priority Service Map

USPS Shipping Map

USPS Priority Express

1-2 business days.

* Please note: All orders placed after 8 am will be fulfilled the following business day.

FedEx 2-Day Shipping

Arrival in 2 business days.

* Please note: Orders placed after 11 am will be fulfilled the following business day.


Additional Information for USA Orders

All orders must be shipped within the USA, Puerto Rico or an APO.
At this time we do not offer shipping to Canada.

All Made-to-Order (MTO) and Jersey for a Cause items are delivered 14-16 days from the date of purchase via FedEx Express. Please note that FedEx cannot deliver to PO Boxes. If you order an MTO item and use a PO Box, your order will be shipped to our Denver office and forwarded to the PO Box via USPS. 

PLEASE NOTE: Information on this page does not apply to custom clothing orders.
For information about Pactimo Custom, please visit


Customer Reviews
4.9 Based on 111 Reviews
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Paul B.
United States United States
when will thermoregulator ls medium be available?

I am 5"7", 140 the thermoregulator ss...tried it when it got cool enough..great..decided I now wanted the ls mediums available...when will they become available, and can I reserve on...TIA

Homer H.
United States United States
Terrific base layer

Works great: warm enough without being too hot. Good sweat wicking too. Wore this on a 50 degree ride under a jersey and stayed comfortable all day. Thanks to all those who before me said these base layers run small. I'm 6'1" 195 lbs, and normally wear an XL. XXL in this garment fit great

Brandon H.
United States United States
great quality - size up

Good base layer with lots of benefits. It fits as a base-layer should - tight. The only sizing peculiarity is its length. Could be a touch longer. It is a little lighter than I expected for a thermo baselayer and it isn't merino wool, but it still does the job well. I've tried it in 40 to 60 degree weather with various jersey combos. Works well.

Robert W.
United States United States

It has been very good so far as this is the first time I have ever used a true base layer. I will use it while riding but I got it to use as a base layer when I ref high school soccer games.

Dennis P.
United States United States
Men's Thermoregulator SS Base Layer

Great product, very warm but lightweight, just make sure to upsize as it runs small

Matthias W.
United States United States
Perfect for chilly rides

Great to add under a jacket on cold days or under a jersey on chilly days. Never overheated, fits the body really well.

Judson C.
United States United States
Great for a little extra warmth

This works great when you want a little extra warmth under a short sleeve jersey. I also have the long sleeve version, but prefer the flexibility of the short sleeve + arm warmers. Wicks very well. A go-to item.

Ivan C.
United States United States
Base layer

Extremely satisfied with the product, well designed and great material, thank you

Kevin W.
United States United States
Best base layer I've worn

It was time to add a couple of base layers since I was still using some from 20 years ago. I like my Pactimo kit so much that I thought I would try the base layer, and honestly, like the bib shorts and jerseys, the Pactimo base layer is the best I have ever used. It is comfortable, and unobtrusive; I never even think about it while I am riding.

Jacob M.
United States United States
One of the best base layers I've ever owned

Love this base layer and wish I had bought more than one. The fit is perfect (I ordered a Large) and love how the material stretches. So far I've paired this base layer with a short sleeve jersey, arm warmers, and a vest for a 45-50 degree ride and I was very comfortable. Anything more and I would have overheated. This is my go-to base layer and I hope I don't wear it out before I can order some more!!

Chris M.
United States United States
Perfect as expected.

Great fit. Comfortable. Appropriate warmth.

Joe L.
United States United States
Perfect base layer

This base layer has been fantastic for layering under my Tellus MTB jersey and road jerseys alike. It's perfect to take the chill out on brisk mornings on the road bike and I never felt like I overheated. I honestly forget it's there which is great. I've been able to go deep in to fall with it on the MTB since there's typically less wind exposure, lower speeds and high intensity. I'll probably get another in long sleeve and use it for ski touring as well cycling.

Stephen M.
United States United States
Thermoregulator base

Great base layer! A tight fit but has stretch to it so not constricting.

Matthew Z.
United States United States
Fits the bill

I layer this under a Perfetto and am good for temps at 45-55. Gets a little warm at that end, so I unzip a bit. Stretchy fabric but tight so I had to size up. Great, functional piece.

Joshua H.
United States United States
Love this base layer

This is one of my favorite items from Pactimo. This base layer is perfect for most chilly, morning rides in the Central Valley of California. With temps in the low 40’s to upper 30’s on some mornings, this and a jersey are often all that’s needed for my upper body (and arm warmers). It’s nicely, snug fitting. I own 2 of them.

Paul W.
United States United States
Must have for fall/winter rides

Thermoregulator base layer, strom short sleeve jersey,arm warmers Comfortable in mid 40's to 50 for 3.5 hrs. Unzipping jersey to regulate temp from overheating on climbs and cool but not cold on downhills. Amazing baselayer PACTIMO!

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