slim fitting poly base layer for slim guy?

How about Asian sizes?

Montbell seems to have them all the time.

How about Patagonia Capilene baselayer? The site description lists them as 100% recycled polyester. The 2017 stock should be on sale soon.

What about trying ‘compression’ layers?

You may look at European companies like Rab.  They tend to be slim fitting.

Try out a size small 32 Degree Heat long undie bottoms from Costco. They fit very close to the skin and weight 4.5 oz. I’m 170lb, 5″8″ and 34″ and they are a snug but fine fit. The mediums are a little more loose, but still tight. And they are very inexpensive. Only issue is Costco usually pulls them from the stores during summer time.

I’m 145 6″1′ and the closest I have found is smart wool NTS. Patagonia capilene is generally too baggy, but their heavy cap 4 stuff is pretty slim.

Agree with Patagonia being quite loose on the torso, but still often tight around the shoulders. In Japan we have Asian size Patagonia, but that also comes with shorter sleeves (I’m 6’1″).

Rab is a good suggestion, as well as shirts marketed or designed/fitted for runners. They’ll often be slimmer fitting if you go to a more focused running shop.

North Face Japan for example has normal fitting hiking gear, but their trail running shirts are much slimmer.

Perhaps see what Salomon or other mountain running brands have to offer?

Hope you find what you need.

I echo the costco base layers are very slim.

Besides the ones already listed have you looked at Sitka ? I can post some pics when I get back in town in a couple weeks showing my bases. I’m on the slimmer side also.

Arc’teryx stuff can run slim.  I’m 5’10”, 150 also, except really I’m like 185.  Some of their “Endorphin” stuff especially looks like its holding on for dear life when I put it on.  When you can see your belly button through fleece is when you need to put the pipe down, and slowly back away. Although I have figured out that high heels and a long pendant necklace lessens this effect.