How to Size Long Underwear Tops?

[itself]

I have to admit, I like to wear everything on the big size. But when it comes to long underwear tops, is it true that you are supposed to wear them so that they are snug?

Thanks!

[Crankin]

Well, I like my tops tight to begin with, but there's a reason for long underwear tops being tight... they don't work well, if they are loose. They need to be tight to wick moisture away from your body and keep the heat in your core.
Plus, you don't want it loose, as that would make it hard to layer.

[Becky]

What Crankin said. I buy my base layers a size smaller than my "casual wear" wool tops.

[itself]

Then why do none of the size charts ever indicate this. I knew I was supposed to take a size down, but they should put something like "if you typcially take a large, size down to a medium."

[Crankin]

I don't size down; I find the tops in my size are tight enough. Craft tops are really tight and I considered sizing up, but then the sleeves would be too long, on top of the fact that they are already made for people 10 feet tall!
I don't think there needs to be a label. You just need to try them on, as this does vary by brand.

[Irulan]

Then why do none of the size charts ever indicate this. I knew I was supposed to take a size down, but they should put something like "if you typcially take a large, size down to a medium."

I personally have never heard "size down". Baselayers are designed to be worn next to the body.( And I have worked in the technical clothing/outdoors wear industry for 15+ years) It's already been said that sizing will vary from manufacturer... but if someone is suggesting to size down perhaps they are looking at using "non-baselayer" items as base layers. There's nothing wrong with that of course.

[Becky]

I should clarify... I'm right between sizes. If I want snug, I go down. If I want something more relaxed and casual, I go up.

[PamNY]

I don't buy a size down; if they are meant as a base layer, they should be sized to fit snugly.

As with all clothing, there are variations. A Smartwool small is perfect for me, while an Icebreaker small is too tight.

[indysteel]

I don't size down either, but do find that it pays to try stuff on. Even within a given brand, the sizing might vary from style to style. I like my baselayers to fit close to my body, but not to the point the I feel constricted.