Arc’teryx Gamma SL vs LT vs MX: Which Gamma Softshell Jacket Is Right for You?

Designed for high-output mountain use, the Arc'teryx Gamma SL, LT, and MX jackets share a similar DNA — durability, mobility, and weather resistance — but are built for very different conditions.

We've tested all variants of the Gamma over the last few seasons. This updated comparison breaks down exactly how the Gamma SL, LT, and MX differ, what activities each one excels at, and how to choose the right model for your climate and use case.

The Arc'teryx Gamma SL is not currently in the product line, but we're hoping it makes a return for Spring 2026. 

Here is how Arc'teryx compares the Gamma Hoody and Gamma MX Hoody.

Comparing the Gamma, Gamma MX, and Gamma SL

What's the same:

• Stretch fabric: While their weights are different, all three jackets use some form of Arc'teryx's Fortius stretch woven softshell.
• Durable Water Repellent (DWR) coating: All three have a DWR applied. The Gamma and Gamma MX have the newer PFAS-free FC0 DWR and we're very confident that the next release of the Gamma SL will follow suit.
• Gamma and Gamma MX pockets: These two jackets have the same pocket configuration (two handwarmer, two external chest pockets).

What's different:

• Warmth: The Gamma MX is measurably warmer than both the standard Gamma and Gamma SL. The Gamma SL is on the other end of the spectrum and favors breathability over warmth. 
• Abrasion resistance: The Gamma MX with 60D face fabric is less susceptible to abrasion and snags. The standard Gamma offers a great balance of durability to weight.
• Liner: The three jackets have different liners. The warmest Gamma MX has a fleece backer that is noticeably thicker and softer than the others. The Gamma has a knit mesh that is soft enough, but not plush like the lining in the MX. It feels much more breathable. The Gamma SL is a single layer Fortius 1.0 fabric which is much more air permeable than the others.
• Hoods: There is a slight difference in the hood adjustment between the Gamma MX and Gamma. 
• Gamma SL pockets: The Gamma SL does not have chest pockets. 

Warmth & Breathability

The Arc’teryx Gamma series is designed around breathability first, but the level of warmth varies significantly between the Gamma SL, Gamma LT, and Gamma MX.

The Gamma SL is the least warm of the three and prioritizes airflow over insulation. Its thin, lightweight softshell fabric allows heat to escape quickly, making it ideal for high-output activities such as summer alpine travel, scrambling, and fast hiking. In cool or windy conditions, the Gamma SL relies heavily on active movement or additional layering for warmth.

The Gamma sits in the middle of the lineup and offers the most balanced warmth-to-breathability ratio. It uses a thicker and more durable stretch woven fabric than the SL, which blocks more wind while still breathing well during sustained effort. Because it has no fleece backing, the Gamma LT adapts easily to a wide temperature range depending on what you layer underneath. This makes it especially effective for shoulder-season hiking, climbing, and backpacking, where conditions and exertion levels can change throughout the day.

The Gamma MX is the warmest jacket in the Gamma family and is designed for colder, more exposed environments. Its fleece-backed softshell construction traps heat far more effectively than the SL or LT, making it comfortable in winter conditions and low-to-moderate output activities. The trade-off is reduced breathability compared to the other models. While the Gamma MX still vents heat better than insulated jackets, it can feel warm during high-exertion movement unless temperatures are low.

While any of these can conceivably be used as a midlayer, I don't use softshells this way. If you own one and want to get as much as you can out of it, then sure you can throw it under a shell and it will provide additional warmth. In my opinion, the Atom, Allium, and in really cold weather the Cerium are all much better midlayers.

Weather Protection

All Arc’teryx Gamma jackets provide weather resistance rather than full waterproof protection, but the level of protection increases as you move from the SL to the MX. Arc'teryx is now using their newer FC0 DWR on all new or updated jackets and we expect the next iteration of the Gamma SL to use it just like the current Gamma and Gamma MX. On these softshells, the DWR is responsible for most of the water repellency. The face fabrics make a difference, but most of the work is done by the DWR.

Washing your jacket and reapplying the DWR coating are essential to maintaining performance in wet weather, as well as breathability. Here is a page from Arc'teryx that details upkeep for softshells, down jackets, and GORE-TEX shells.

The Gamma SL offers basic defense against wind and light precipitation, enough for brief exposure in fair weather. Its thinner fabric sheds light moisture and blocks some wind, but it is not intended for prolonged exposure to harsh conditions. In our experience the SL wets out after 15 minutes in even a moderate rain.

The Gamma improves significantly on wind resistance and durability while still maintaining good breathability. Its denser face fabric blocks wind more effectively and resists light rain and snow better than the SL. While it is still not waterproof, the Gamma LT performs well in variable mountain conditions where short bursts of weather are common. For many users, it provides enough protection to avoid reaching for a hardshell during short rains or windy days. It isn't enough though if the wind is really cold. 

The Gamma MX offers the highest level of weather protection in the Gamma lineup. Its thicker fabric and fleece backing help block wind more effectively and provide better resistance to cold, damp conditions. Light snow, drizzle, and sustained wind are handled comfortably, especially when paired with appropriate base layers. However, like all softshells, the Gamma MX is not a substitute for a waterproof shell in heavy rain. Instead, it excels in cold, mixed weather while the stretch fabric allows for more movement than a hardshell.

Pockets: Arc'teryx Gamma vs. Gamma MX vs. Gamma SL 

The Gamma was updated in 2025 with dual external chest pockets, to match what the MX already had. With the standard Gamma I often complained that the internal chest pocket was hard to get to when I had the chest strap on my backpack clipped. As a backpacking softshell moving the pockets to the outside was a great move. When it comes to the Gamma MX, I often have my phone in one pocket and then a skull cap and Dermatone in the other.

The superlight and simplified Gamma SL has two handwarmer pockets, but no chest pockets. It would be nice to have a chest pocket on the inside for car keys or phone when hiking, running.

Arc’teryx Gamma: The Most Versatile Softshell in the Lineup

The standard Gamma is the most popular and versatile jacket in the Gamma family. It strikes an ideal balance between breathability, durability, and weather resistance. This is your 3-season hiking shell, as long as you encounter only the occasional rain storm. If you need more protection then you should be looking at a GORE-TEX jacket like the Arc'teryx Beta series. (You can see our full look at the Beta jackets here.)

The Gamma is built for:

• Hiking
• Backpacking
• Climbing

Unlike the MX, it remains uninsulated, which allows it to perform across a wide temperature range depending on your layering system.

This makes the Gamma LT a true do-everything softshell — capable of handling everything from shoulder-season hiking to alpine climbing.

Best for: Hiking, climbing, backpacking, all-season versatility.

Arc’teryx Gamma SL Jacket: Lightweight Performance for High Output

The Gamma SL (Super Light) is designed for fast-moving objectives in mild conditions. It uses a thinner, more breathable fabric than the Gamma and Gamma MX, making it ideal when overheating is a bigger concern than weather protection. In the rain we found it provides decent short-term protection, but wets out after about 15 minutes. This jacket is a great choice if you prefer an superlight softshell to a windshell, otherwise I'd consider Squamish (men's / women's) or Norvan (men's / women's) jackets. 

Fabric: Fortius 1.0: 86% nylon, 14% elastane. 4.7oz/yd2, 160g/m2

The Gamma SL is built for:

• Summer alpine travel
• Cool-weather trail running
• Rock climbing and scrambling
• Minimalist layering systems

Because the fabric is thinner, the Gamma SL offers limited wind and abrasion resistance compared to the other models. However, it packs down small and feels barely noticeable when worn, making it a favorite for weight-conscious users.

Best for: Warm to cool conditions, high-exertion activities, minimalists.

Arc’teryx Gamma MX: Warmth and Protection for Cold, Mixed Conditions

The Gamma MX (Mixed Weather) is the warmest and most protective jacket in the Gamma lineup. It features a thicker face fabric and a light fleece backing that adds noticeable warmth. While it offers excellent weather resistance for a softshell, the trade-off is reduced breathability and increased weight. The Gamma MX is not ideal for high-output activities unless temperatures are cold. Obviously a great jacket for ice climbers, but for me this is more of a great everyday work jacket for cold weather. 

The Gamma MX is built for:

• Cold-weather climbing
• Winter hiking and mountaineering
• Windy, variable alpine conditions
• Work jacket for fall/winter

Best for: Cold climates, low-to-moderate output, winter mountain use.

Women’s Arc’teryx Gamma MX Coat: Extended Coverage for Cold, Mixed Conditions

The women’s Arc’teryx Gamma MX Coat takes the warmth and weather resistance of the Gamma MX softshell and extends it into a longer, coat-length design for added protection. Built for cold, windy, and variable conditions, it offers more coverage through the hips and thighs while maintaining the stretch and breathability that define the Gamma line. With a garment centre back length of 36 inches (92 cm) in size small, this model fits squarely between an active softshell jacket and a casual winter coat, making it well suited for winter travel, cold-weather commuting, and everyday outdoor use where extra warmth and coverage matter.

FAQ: Arc’teryx Gamma SL vs LT vs MX

What are the main differences between Gamma SL, LT, and MX?

The Gamma SL is the lightest and most breathable, the Gamma LT is the most versatile and durable, and the Gamma MX is the warmest with the best weather protection. Here is how Arc'teryx compares the Gamma jackets.

Which Arc’teryx Gamma jacket is best for hiking?

For most hikers, the Gamma LT is the best option due to its balance of breathability, durability, and wind resistance. The SL works well in summer, while the MX is better for winter hiking.

Is the Gamma MX waterproof?

No. Like all softshells, the Gamma MX is water-resistant, not waterproof. It handles light precipitation well but should be paired with a hardshell in heavy rain.

Are Arc’teryx Gamma jackets worth the price?

If you love softshells, yes. The Gamma series is made with the fit and quality we expect from Arc'teryx. These jackets rank very high compared to any other softshell when it comes to dependability in alpine environments.

Can you layer a Gamma jacket under a hardshell?

Yes. The SL and LT layer easily under a waterproof shell. The MX can also be layered but is bulkier due to its fleece backing. If using the Gamma as a midlayer if your priority, then get a non-hooded jacket version. The bulky helmet compatible hood annoys me when I'm layering.

How warm is the women’s Gamma MX Coat compared to the Gamma MX jacket?

The women’s Gamma MX Coat provides a similar level of core warmth to the Gamma MX jacket, but the longer cut adds noticeably more overall warmth. By extending coverage over the hips and upper thighs, the coat helps retain heat more effectively in cold and windy conditions. The fleece-backed softshell construction traps warmth while still allowing some breathability, making it ideal for cold-weather use without feeling bulky. See the latest women's Arc'teryx Gamma MX Coat here.

How long is the women’s Gamma MX Coat, and where does it fall on the body?

In size small, the women’s Gamma MX Coat has a garment centre back length of 36 inches (92 cm). On most wearers, this length falls to mid-thigh, providing extended coverage without reaching full parka length. The longer cut helps block wind and cold while still allowing comfortable movement for everyday use.See the latest women's Arc'teryx Gamma MX Coat here.