That's one smart sock.

SmartWool's PhD Running Ultra Light Low Cut Sock earned its degree in technical performance with a minor in the utmost comfort. ReliaWool technology uses merino wool for ultralight temperature regulation, natural odor-resistance, and long-lasting durability. SmartWool's 4 Degree elite fit system uses elastic bands at the ankle, upper instep, lower instep, and arch for greater stretch and recovery. This smart sock also features a virtually seamless toe and mesh ventilation zones for extra comfort.

  • ReliaWool technology
  • Naturally antimicrobial
  • 4 Degree elite fit system
  • Mesh ventilation zones
  • Virtually seamless toe
  • Reviews
  • Q & A

Comfortable

    Comfortable

    Very Nice!

      Great design, fits well, perfect height!
      Very comfortable. Bought several.

      PhD for the Win

      • Familiarity: I gave it as a gift but have feedback to share

      Bought these for a friend, he had this to say:
      Favorite sock for warm weather running - great balance of cushion, breathability, cut, and feel inside the shoe (no slippage). Not to mention the freedom from funk that comes with Merino. Great socks.

      Learn More: Smartwool PhD Socks

      Learn more about the comfort, fit, and durability of Smartwool PhD performance socks. #gofarfeelgood

      PhD makes all the difference

        I would agree that at first I was a little skeptical and thought it was just a way to add on some extra cash to the price tag. But once I tried them out, I immediately realized it really does make a difference in how the sock forms over your foot and adds to the performance. I highly recommend them.

        Great sock!

        • Familiarity: I've put it through the wringer

        Very comfortable sock for running, good ankle height!

        Great for Running!

        • Familiarity: I've used it several times

        I like thin light weight socks for running, these work really well.

        No heel slipping!!

        • Familiarity: I've used it several times

        Not a runner, but I wore these with some trainers at the gym to replace some old "no show" socks that slid off my heels and these did the job. No heel slipping here! They were so thin I could barely feel them, but i did miss the toe and heel cushioning- personal preference. My feet did not get too hot or sweaty. SmartWool did a great job on the moisture wicking and temperature regulation. They have been through a couple of washes and still feel like new! will be buying more.

        Good cut

        • Familiarity: I've used it once or twice and have initial impressions
        • Fit: True to size
        • Size Bought: M

        Most of Smart wool sock cut is either to low like the mini one or very high crew socks. This is more like normal 3-4 seasons cut, high enough to cover my base layer bottom and not too high and not too warm like crew socks only made for winter. This is more natural cut socks. I like it.

        Men's PhD Run Socks

        Professional Ultra Runner & Fan Field Tester Timothy Olsen shares how the PhD Run socks help him go far, and feel good.