Not too thin...Perfect.
I read quite a few reviews on these before buying them and almost went with the midweight because someone said they ripped theirs pulling them on which indicated to me they were very thin. They are thin but not as thin as I thought and you would really have to try hard to rip them. Perfect. Love em.

Love Smartwool
I was looking for thermals that weren't too hot, light weight and warm. They are perfect to wear under my scrubs in FL. I plan on ordering a set of the midweight to take with me next month when I go snowboarding.

Perfect base layer
I am very pleased with microweight bottoms in black color from Smartwool. I purchased encouraged by high quality of previously purchased socks... I highly recommend them for cold weather as a base layer or for lounging around house. My only complaint is they are shorter than ideal for me (I am 5'10" tall). Additional two inches of length would be perfect for me.

the perfect wool leggings
I have been looking for a pair of wool leggings for 2+ years now since I moved to Ontario. Just got these and they are (almost) perfect! Very thin and light, but not see-through. Can be worn outside for running, inside as lounge pants/sleep pants, or as underpants when it's really cold. Appropriate as tights under a casual sweater dress or skirt too. They were very slightly itchy- but just very very slightly- when I first put them on because my skin is fairly dry, not because I'm sensitive to wool. It didn't bother me, but I'm not sure if it might bother someone who is sensitive to wool. After washing they became even softer. The fit is true-to-size in my opinion. I am a size 0 regular, and the XS is a good fit. The waistband is also very comfortable- not too tight or loose. They will be very well used this winter. Highly recommended.

Comfy & Doesn't Hold Odor!
Wool just can't be beat in my opinion for moisture handling, comfort, and NOT holding odors. I wash these in cold and line dry and have had no shrinkage. Medium fit perfectly...I'm 5'5" and 128lbs. Great as leggings under a skirt too. I found the microweight warm and easy to wear under jeans, or as PJ's alone. They scrunch up pretty well for packing/travel too. Kept me warm on a 38 degree morning hauling wood. Wore a pair camping over the weekend, and everyday, and they did not stretch out. Maintained good fit and comfort the whole time. Highly recommended!