Icebreaker Women's Bodyfit 150 Long Sleeve Crewe

Women's version, really lives up to the hype. Definitely worth the money.

Merino wool keeps sheep warm in winter and cool in summer. Period.  It will do the same for you. Once you go wool you're never going back to synthetic for base layer comfort.

I always smelled like a barn animal after hiking and camping in a synthetic base layer. No problem anymore. Not only does the merino shirt do better it actually inhibits bacterial growth, the difference is overwhelming.  This material is not the scratchy old wool I remember from childhood. It's spun or processed into a super soft, natural, next to skin feeling. Winter or summer my first choice is merino wool.  

Other brands to look for are Stoic, Ibex, and of course Smartwool. I scour the outdoor internet retailers for clearance to get the best deals. You don't get the all encompassing color/size choices but keep looking, especially in summer, and find super discounts. Unless you're allergic give this a try and you'll be glad. The small extra expense is worth it!