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Outdoor Research Helium Pant - Women's Review

These are the ultimate lightweight model.
Top Pick Award
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Price:  $119 List | $89.19 at REI
Compare prices at 3 resellers
Pros:  Ultralight, athletic fit, affordable
Cons:  Less durable, clammy feeling
Manufacturer:   Outdoor Research
By Lyra Pierotti ⋅ Review Editor  ⋅  Apr 19, 2018
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#3 of 9
  • Water Resistance - 25% 8
  • Comfort and Mobility - 20% 8
  • Breathability & Venting - 20% 7
  • Weight - 15% 10
  • Packed Size - 10% 10
  • Features - 5% 7
  • Durability - 5% 8

Our Verdict

The Outdoor Research Helium pants are as light as advertised. They are a rain pant that you don't even have to debate about bringing with you—they're so light, just throw them in your pack and go. As a niche pant, these are not the most versatile in this review, but they perform phenomenally well for their weight. They feel a bit clammy, but if you're moving fast, your body heat will pump enough moisture through the pants to improve the feel. These pants are an excellent value, and well worth the cost even if they are narrower in utility.

Product Updated

Outdoor Research updated the Helium Pant since our test period with bluesign approved material that is designed to be more tear-resistant. The fit may have changed slightly, as well. This new version is available exclusively at REI right now, and will be available at other retailers starting in Fall 2020. So, for the latest model of the Helium, hit up REI. If you don't mind an older model (the version we tested and published this review about), the other retailers may be having sales on this product now.

March 2020

Compare to Similar Products

Our Analysis and Test Results

If light weight is your priority, these are your rain pants. They are the lightest, genuinely waterproof pant we have ever seen. They are not the most versatile pants in this review, but they are exceptionally well suited to fast hikers in rainy climates. As such, they got our Top Pick for Lightweight Rain Gear.

Mountain running and ultralight hiking are the best applications for these pants. They are not meant to be layered over warmer pants or to be put on while wearing big boots, so they are optimized for milder climates. We recommend wearing tights or knee-length shorts under these pants because of the clammy, sticky feel of the pants—the can tend to stick to your skin, especially when wet or humid.

These pants are so lightweight that they will slide easily into your ultralight backpack. They are great for longer trips where you don't have a reliable forecast, but you suspect good weather, so you don't want to take rain pants, but you think you probably should, just in case. These pants make that decision easy: stuff them in the bottom of your backpack and forget about them until the sky cracks open, then slip them on and keep on trekking!

Performance Comparison

Water Resistance

We have become increasingly familiar with Pertex fabrics in a range of garments—from down jackets to hard shells. The various types of Pertex have become some of our favorites, from the wind resistant and warm Quantum to the waterproof Shield lines. Pertex focuses on light weight and is an excellent choice for the OR Helium pants. Pair this with the Helium jacket, and you have an ultralight, storm-ready summer mountain kit.

In our tests, these pants kept us dry while hiking and even running. The waterproof 1/4 length side zippers are waterproof, reducing any chances for leakage. There is a back pocket with a flap over the zipper instead of a waterproof zipper. This makes it easier to invert the pocket and stuff the pants into the pocket, but it is not typically our favorite waterproof zipper design. However, this is a much better orientation than side pockets or side zippers with storm flaps instead of waterproof zippers: The flap is ideally placed to block drips in the direction of gravity—whereas side zippers with storm flaps can get drips running along the length of the zipper in really torrential downpours.

The tapered legs make these pants easy to move fast in.
The tapered legs make these pants easy to move fast in.

Comfort & Mobility

The Helium was our go-to rain pant for wet weather running. They are nicely tapered to keep the pant legs from flopping around when moving quickly.

They are not optimal for layering over warm pants—rather, they are best suited to fit over running tights. We recommend wearing them over tights that cover your knee. The gusseted crotch of these pants help them move with you, but in humid, rainy weather, we found that the more plastic feel of the material inside also made it more likely to stick to our skin.

An adjustable draw cord at the waist keeps these pants in place.
An adjustable draw cord at the waist keeps these pants in place.

The extreme light weight of these pants also helps them feel more mobile for your high energy activities—it is less fabric to move around and feels as if it floats with you, keeping rain out.

Breathability & Venting

These pants don't have any vents, and the only zippers are the 1/4 length side zippers that help you get them on over shoes.

The fabric, however, is so light weight that we found them to be very breathable.

The tapered legs  up close  with the short ankle zippers.
The tapered legs, up close, with the short ankle zippers.

The Pertex Shield is a 2.5 layer waterproof fabric—2.5 layer rain shells often have that more plasticky feel on the inside, and can feel clammy when wet. We found this to be the case, not surprisingly. However, the fabric is so thin that the moment we picked up the pace, our body heat would pump out all the moisture from our body, and dry any wet patches on the pants, too.

In the end, we gave the Helium a 7 out of 10 for Breathability & Venting. It got knocked down for the lack of vents and clammy feeling but boosted back above average for the speed with which it would breathe and dry us off. As this is an excellent pair of pants, optimized for fast and light mountain sports, we think their performance in this category was ultimately very impressive.


Wow. Phenomenal. These pants weighed in at 3.5 ounces for a small pair. At that weight, it's hard to justify not taking them with you on every adventure.

These pants are so light that we were able to do some trail running in them—and not have to hesitate about whether or not to put them in our light backpack for a long trail run. We love gear that makes it easier to pack, and which keeps us motivated to get outside despite wet weather. This is such a great, light rain pant that it's easy to throw them in the bottom of your backpacking pack for a week-long trek, just in case the weather takes a turn for the worse that wasn't predicted in the forecast.

The OR Helium are the lightest and most packable pants in this review  and possibly the world...
The OR Helium are the lightest and most packable pants in this review, and possibly the world...

Packed Size

Perfect 10, just like the Weight metric above. These pants are so small, light, and packable that we never had to question whether or not we really needed to lug rain pants along on our next mountain adventure—at 3.5 ounces, we could just throw them in the pack and go.

These pants can be stuffed into their back pocket, revealing a clippable loop, in case you want to clip it to anything. We find this feature to be much less useful on pants than on jackets—with jackets; it's great to have quick access to a jacket clipped to your harness if the weather turns or the wind picks up while on your climbing route. But pants require more time and stability to get them on, so we didn't feel we needed to clip them to our harnesses for rapid access.

This pouch, however, does provide a level of protection for the pants if you need to stuff them in a bag with sharp objects, and keeps them tidy and organized for neat packing in a travel bag or duffel. Be careful; however, when stowed in its pocket, these pants are so small we were almost worried about losing them!


These pants are highly specialized to be ultra lightweight. As such they are not full of features—but OR has carefully chosen features that contribute to their utility and light weight.

We love the single zippered back pocket. We love pockets, but hand pockets are not as ideal on rain pants—who wants to put wet hands in rain pants pockets anyway? The waist has OR's signature grippy elastic band that helps keep the pants in place and works very well.

The adjustable elastic drawcord is easy to use and useful. The similar design of the cuffs ensures they stay in place around boots. If you venture into snow or go off trail, you can tie a cord to the loops inside the cuffs and hook that under your shoes to keep the pants secure over your shoes, not unlike how gaiters work.

The waist is a clever combination of grippy elastic band and cinching draw cord.
The waist is a clever combination of grippy elastic band and cinching draw cord.

The 1/4 length side zips ensure you can get these pant on over shoes, but not boots. This is appropriate for these light pants—they are not thick or rugged enough to be an all-mountain or winter-ready shell pant. These are ideal for mountain running where you might get caught out in a storm in shorts (or running tights) and a t-shirt, and you want something to keep you dry.


These pants are very lightweight and as such not the most durable, for a couple of reasons. First, the material is more susceptible to wear and abrasion due to how thin it is. Second, the 2.5 layer material, especially with this design being so close to your skin, provides less protection on the inside from skin oils and dirt—this has to do with the half-layer that protects the waterproof membrane from your skin. The upside is the light weight, however—these 2.5 layer shells are often the lightest available.


These pants are a specific use rain pant, so they are not the most versatile. However, if light weight is important to you, these are a great choice and well worth the cost. They are not much more expensive than our Best Buy winner, the Marmot PreCip, and they are much lighter. In that sense, these pants are a bargain for the right buyer.


The Helium line of rainwear is an impressive feat of ultralight shell technology. We loved the Helium pants for their light weight and comfortable, tapered fit. We found them to be much more limited in versatility, but excellent in the niche of lightweight active rain shells. If you live in a rainy climate, these pants will help to maintain motivation to go on your morning run, rain or more rain.

Pertex Shield plus provides another amazing  lightweight product.
Pertex Shield plus provides another amazing, lightweight product.

Lyra Pierotti