The double layer knit is the real winner here, no bulk but noticeably warmer than my old single-layer thermals. I've washed it three times now and the seams are holding up fine.
Sofia★★★★★
Wore this under a thin sweater for a cold morning walk and never felt a chill. The crewneck sits smooth against my skin with no bunching, and the double layer fabric doesn't add bulk under my clothes.
Victoria★★★★★
I’ve worn this on a few chilly morning runs and the double layer jersey really traps heat without feeling bulky under my jacket. The crewneck sits nicely and doesn’t ride up, which is rare for base layers I’ve tried. Soft enough against the skin that I forgot I had it on.