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Hiking Socks and Sock Liners

Hiking Liner Socks
Hiking Liner Socks Help Prevent Blisters

Sock liners are thin wicking socks worn underneath a heavier hiking or snowsport sock. The biggest benefit they provide is blister prevention, particularly when you are wearing a stiff leather hiking, mountaineering boot or skiing boot that has very little give to it. They’re often not needed for softer synthetic boots or if you wear a low hiking shoe like a trail runner.

Blister Prevention

Sock liners prevent blisters in two ways: they wick moisture away from your feet which can lead to increased friction and they help prevent ill-fitting boots from rubbing your skin and causing a hotspot.

Foot Sweat

When you wear boots, your feet generate about half a cup of perspiration per day, which explains why your socks are often damp when you take your boots off. This is particularly true if you are wearing a mid or over-the-ankle hiking boot which traps this perspiration unlike a running shoe which is much better vented. Further, so-called breathable Gore-tex or other waterproof membranes cannot vent this much perspiration in a day and are easily overwhelmed, which is why your socks will still remain damp even if you’ve invested in a breathable boot.

Sock liners work like any other base layer by efficiently transporting, also called wicking, your perspiration to the next outer layer of your clothing system and away from the surface of your skin. Very thin, non-absorbent sock liners are the best for wicking sweat up to a thicker, outer sock.

Personally, I prefer wearing very thin synthetic liner socks, thin nylon business dress socks, or wool liner socks woven with a significant amount of nylon or spandex for this purpose. I’d had good luck with REI Coolmax Liner Socks, Gold Toe Nylon Dress Socks, and REI Wool Liner Socks, which have proven quite durable when worn under a thicker hiking or mountaineering sock. Whichever liners you choose (be sure to avoid cotton liners), they should be thin and well-fitting, without any bunching around the toes or rough seams that will irritate your feet.

Smartwool Merino Wool Sock Liners

Hotspot Prevention

Hotspots are precursors to blisters. They’re caused by friction, especially when your foot has too much room to move around inside your boots, your boots are too hard and not well broken-in, or you have an anatomical issue with your foot such as a bunion or hammer toe that rubs against the inside of your boot.

The function of socks is fill up the inside of your boots so your feet don’t slide around in them and to prevent a boot from rubbing your skin raw and creating hotspots. If you wear a soft mid or over the ankle hiking boot that’s made out of synthetic fabric, you can often get away with wearing a single hiking sock of medium to heavy thickness and not get any hotspots or blisters. Lighter snthetic boots like this have a lot more give to them than old-fashioned leather hiking or mountaineering boots which have little to no give at all.

For heavier boots, it’s best to wear a sock liner together with a medium to heavy sock, depending on the room available inside your boot. When you wear two socks with these harder boots, the boot rubs against the outer sock, but not the inner sock, which remains snuggly fitted around your foot. With two socks, all of the  friction occurs between the two layers of socks and not between your sock and your skin, which is why the two sock system works so well.

This post was written in response to a reader question about sock liners, when to use them, and how a two-layer sock system can prevent blisters. 

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  1. When I’m not wearing my heavier winter boots, I’ll wear trail runners. With those I like to use a very thin wool liner sock only. Sometimes I just wear the ankle height coolmax synthetic socks in the summer. I got a 3 pack of merino wool liner socks from Costco for $10! I’m always surprised at some of the quality outdoor clothing that place has for cheap.

    • I also use very thin liners for trail runners. They’re soft and my feet are permanently hard so there’s no need for extra protection. There I find that nylon business socks ar ethe most durable against grit which becomes a big issue on sock durability on multi-day hikes.

  2. Sorry but I guess I am unusual as in when I wore sock liners I got more blisters and not less. They seem to be pulled down and bunched up under my Wool socks at the achilles and heel as well as the Smart Wools when they came on the market. So I stopped wearing them. No problems since. My boots fit perfectly, their Danners and the last they use is the same one I wore while in the Military and never experienced a blister hiking in combat boots, so their perfect for my foot at 9 and a 1/2 whereas all the other boots I have to wear a 10 – 10 1/2. So it is not the boot. Plus it makes two pairs of socks I have to wash out at night and in the desert that means twice the amount of water. Maybe they work for some but not me…

  3. One of the best tips I ever got was from a racquetball instructor (one-credit course) back in college. I had gotten terrible blisters almost immediately. He told me to get nylon knee-highs in the women’s section (Target, Walmart, etc). Vaseline on the skin at the hotspots, knee-highs next, and then regular socks last. It works great! They’re very thin, inexpensive, and readily available. They are not extremely durable, but they are so cheap, and light, you can take a few pair along and not even notice the extra weight or space they take up. They are best for reducing the friction. I also like the REI liners, which work better for wicking, probably. The knee-highs also don’t bunch up, BTW.

    • Interesting – I discovered exactly the same thing. Sheer knee-highs (15 or 20 denier), 100% nylon with a reinforced toe works best which is great because they’re usually the cheapest.

      I found that you have to wear them loose, to ankle/calf, rather than pulling them tight to the knee, in order to get the best warmth, but it seems like magic that something so thin works to keep my toes so warm.

      I guess it’s the low thermal mass combined with breaking the moisture bridge that makes this work.

  4. I wear toe socks from Injinji and they are great at preventing the blisters I used to get between and under my toes. I guess just the separation works let everything slide vs. rubbing. Let me hike 131 miles at Philmont in 11 days without a blister.

  5. I must be a contrarian — I’ve never used liner socks. DeFeet Wooleator for my trail runners, Medium weight Darn Tough socks in my mountaineering boots. Never had a blister…

  6. I’m having difficulty keeping my feet warm and dry. I have good Sorel boots but my feet sweat (in spite of being cold), making the socks wet and then they make me even colder. The problem is inside the boot, not moisture getting in. If I wear sock liners under thermal socks, will that do the trick? And if so, what sock liners / socks would you recommend for wicking moisture away from my foot WITHOUT making the outer thermal socks damp (and therefore cold)? It seems I’m stuck between a rock and a hard place: insulation keeps me warm but makes me sweat, breathable keeps me dry but isn’t warm enough. I’d appreciate some knowledgeable commentary. thanks!

    • Buy some Reynolds Large oven bags and wear them over your liner socks and under your warm outer socks. This will prevent sweat from making your outer socks wet – winter hikers do it all the time. Alternatively, cover your feet with antiperspirant.

    • Tracey, if you have good breathable boots, then I would try a coarse-ribbed cotton or wool sock over a thin sheer nylon knee-high inner sock (but worn loose, to the calf). The nylon will provide a wicking air barrier to the wool, and the ribbing will allow airflow to carry evaporated moisture out of the boots.

      Along with this, you might try easing off how tightly your boots are laced to your feet – though obviously you need to make sure you still have ample support, but it could be you’re clamping the moisture inside by having tight or uneven lacing.

  7. Thanks Steve. I have found some relief by using liner socks with Redhead pure wool socks, and you’re right about the boots needing to be slightly looser. In exceptionally cold weather I’m also using toe warmers, and that seems to be providing the extra help to prevent dampness. I think the knee-highs is also a great idea.

  8. Okay so here’s a question. Do you think it matters much if you use the cool max vs the wool liners from REI? I was looking at them and couldn’t decide. I have pretty warm socks to wear over them,but I dunno. Immediate next trip is Patagonia. Thanks!

  9. Hi, and what about a double boots. I mean the ones that has an additional bootie inside the boot. Is there any benefit of wearing liners with that kind of boot?

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