Comparison of Base Layer Materials
‘Base layer’ is the name given to an item of clothing worn next to the skin during sport or activity.
A variety of materials are used for such garments, each with different pros and cons. Below I have set out to review the basic advantages and disadvantages of a few of the more common types, and compare which is best for any given situation.
It is typically the case, particularly in the UK, that you will want such a garment to quickly remove sweat (a process known as ‘wicking’) because if it doesn’t then you get wet and that makes you cold. That’s not always desirable though. If, for example, you’re in a hot desert, then will you want the opposite.
I’ll refer to tops during the rest of the article but most of the content could just as well be applied to bottoms.
The most common type of base layers are probably the broad category of synthetic. These are generally fairly cheap, hard wearing and give by far the best wicking performance (i.e. they retain the least sweat). Cheaper ones from sports stores, as opposed to more expensive ones from outdoor shops, can be a bit itchy and uncomfortable but generally they’re alright even for days at a time.
They retain their shape much better than the natural options below too which means you can get a tighter fit, resulting in better insulation and wicking.
Their main flaw is the smell. Even the best types can start stinking within a couple of hours’ heavy use. That’s fine if you’re on your own, in a remote area and/or just on a short trip. For longer expeditions, it can be a little unpleasant, both the smell and the feel.
I’ve had a long sleeve Helly Hansen top for over a decade and use it all the time for running, cycling and shorter trips in the hills. It looks no different from the day I bought it, has performed brilliantly in all circumstances and has an excellent cut for a tall, skinny guy like me.
Best Synthetic Base Layers
- Helly Hansen Lifa Wear: The original and best with consistent good reviews. Good cut: long in body and sleeves, and close fitting for better wicking. They’re tough and come with the iconic stripes on the sleeves.
- In truth, it’s hard to go wrong with a synthetic baselayer so choose any you like from this range. Base layers designed for sport, like Under Armour or cheap Decathlon tops, tend to smell the worst quickly (less of a problem for a 90-minute game followed by a shower).
A popular alternative to the synthetic option described above is to use merino wool. It’s most notable for its incredibly odour eating ability. In contrast to the Smelly Helly, these can sometimes be worn for days or weeks at a time during activity and still smell passable in enclosed areas.
They have a softer feel than synthetic tops which makes them feel warmer when you first put them on. Some people prefer the feeling, others find them a bit scratchy.
They are notably more expensive than synthetic tops and not as tough (one of mine has holes in both wrists after two years).
Even the thinnest types of wool tend to be warmer than synthetic tops so they are better suited to colder environments and less intense activity, particularly as they don’t wick as well (better than cotton but not a patch on synthetic). Running on a cold UK winter’s day, I found mine getting saturated with sweat and, similarly, my team mates skiing hard towing a pulk in Svalbard at -15C still preferred the more efficient wicking of their synthetic tops.
These tops really shine on longer trips. If you are travelling for several weeks or more, or undertaking a less strenuous activity like walking or cycle touring, then they are really good.
Best Merino Wool Base Layers
- Icebreaker Merino Wool Baselayers: Probably the most popular brand, Icebreaker are a New Zealand company who make great quality tops. I have something similar to the Men’s Mondo Zip Top. They are quite expensive but they have a cheaper Everyday range.
- TrekMates: Good for cheap merino wool baselayers
- Other brands include Smart Wool, Wool Power and Rab.
In the last couple of years, clothing using bamboo in conjunction with other materials such as cotton and lycra has started appearing. Bamboo is similar to merino in many respects – it wicks reasonably well and has impressive anti-bacterial properties.
I’ve only had bamboo clothing for a couple of months* but, so far, would rate it slightly above merino. It seems to be a closer fit, marginally better wicking (although other reviewers disagree with this), nicer against the skin and feels a touch tougher. Best of all, it tends to be slightly cheaper than merino.
N.B. In some sort of exotic material one-upmanship, there are some base layers now available using coconut shells. They are even less common than bamboo and I’ve yet to try one out.
Best Bamboo Base Layers
Bamboo base layers can be a little tricky to get hold of…
- BAM: A British company who produce a whole range bamboo base layers and other bamboo clothing. The quality is excellent (and thus they are not the cheapest) but I’ve found them to be quite thick and heavy, meaning they are warm and take a long time to dry.
- TrekMates: Apparently no longer produced, the TrekMates bamboo base layers were superb (I’m wearing one in the picture above). Keep your eyes peeled for them on GO Outdoors, otherwise try Google shopping and eBay.
Often treated like the devil’s own weave in an outdoor environment, cotton is rubbish at wicking. It saturates quickly and can be slow to dry out. For cool or cold conditions, cotton is not very good. However, in warmer temperatures, it’s great.
Because a cotton base layer retains a lot of moisture, it helps you keep cool and minimise water loss which are both useful properties in hot, dry places. In contrast, tight fitting, fast wicking tops will make you hotter and drain moisture from your body quicker.
I’ve used a long sleeved cotton shirt I bought in a supermarket for several trips. Aside from a desert crossing and mountain walking in hot Oman, it was also infinitely preferable to my bamboo and merino tops whilst hiking in a Patagonian summer – cooler and better sun protection.
Cotton is cheap, readily available, and tougher than bamboo and merino.
- Synthetic Baselayers: Best for intense activity, value for money and shorter day/weekend trips (where the smell doesn’t matter so much). You could do a lot worse than Helly Hansen baeslayers.
- Merino and Bamboo Baselayers: For longer trips, colder environments, or where it’s preferable not to stink, merino is the safe bet and I’d personally recommend trying bamboo (ideally TrekMates rather than BAM, if you can find them).
- Cotton: In hot places, just get a cotton shirt.