Legion vs Promix
Two of the most science-forward clean-label whey brands compete head-to-head. Legion built its audience on no-prop-blend transparency and Irish grass-fed isolate. Promix built its audience on small US family-farm sourcing and dietitian-led formulation.
Overview: Legion Athletics
Legion launched in 2014 with founder Mike Matthews aiming to build a supplement brand based on fully disclosed, no-proprietary-blend formulas. Whey+ is the flagship product: 100% whey protein isolate sourced from grass-fed Irish dairy cows, sweetened with stevia and erythritol, no artificial dyes or fillers. The brand is Informed Choice certified for athlete safety and publishes per-batch testing.
We currently track four Legion SKUs including Whey+ (multiple flavors), Casein+, and the Plant+ blend. The flagship 2 lb Whey+ tub lands around $54.99 at standard pricing, with subscribe-and-save dropping to about $49.99. Flavors include Mocha Cappuccino, Chocolate Peanut Butter, Birthday Cake, Salted Caramel, Strawberry Banana and Dutch Chocolate. Sells direct through legionathletics.com plus full Amazon distribution.
Overview: Promix
Promix launched in 2011 from a Pennsylvania-based athletic nutrition operation, co-founded by registered dietitian Albert Matheny. The brand sources whey concentrate from small US family farms practicing grass-fed dairy (primarily Pennsylvania, Wisconsin and Midwest). Promix sweetens with organic cane sugar or stevia, avoids artificial colors or flavors entirely, and emphasizes supplier transparency.
We track four Promix SKUs: Original Whey, Whey Isolate, Casein, and a plant-based blend. The flagship 2.5 lb Whey bag lands around $59.99 standard, or $54.99 on subscribe-and-save through promixnutrition.com. Flavors include Chocolate, Vanilla, Cinnamon Bun and Iced Coffee. Retail availability is direct purchase plus limited Amazon presence.
Head-to-head comparison
| Metric | Legion Whey+ (2 lb) | Promix Original Whey (2.5 lb) |
|---|---|---|
| Tub size | 907 g / 2 lb | 1,135 g / 2.5 lb |
| Servings per tub | 30 | 32 |
| Protein per serving | 22 g | 26 g |
| Carbs per serving | 1 g | 5 to 7 g |
| Fat per serving | 0 g | 2 g |
| Total protein per tub | 660 g | 832 g |
| Lowest tracked price | $49.99 (subscribe) | $54.99 (subscribe) |
| Cost per gram of protein | $0.076 | $0.066 |
| Protein form | 100% whey isolate | Whey concentrate |
| Sweeteners | Stevia + erythritol | Organic cane sugar or stevia |
| Sourcing | Grass-fed Irish dairy | US small family farms |
| Third-party testing | Informed Choice certified | Third-party batch testing |
| Flavor count | 8+ across SKUs | 4 |
Value Score breakdown
Promix has the slight edge on per-gram pricing because it uses concentrate (which costs less to produce than isolate) and packs more protein per scoop (26 g vs 22 g). Over a year of daily use, Promix costs about $545 at subscribe pricing. Legion comes in around $620 at the same usage pattern. The $75 annual gap is not huge but it is real.
However, the Legion premium buys you a true isolate product with cleaner macros (1 g carb, 0 g fat per scoop). For cutting protocols where every gram of carbohydrate matters, that is worth paying for. The Whey+ flavor lineup is also dramatically wider than Promix, with rotating seasonal options like Pumpkin Spice Latte and Peppermint Mocha that add daily-use enjoyment.
For a comparison with another isolate-based competitor, see our Legion vs Transparent Labs matchup.
Flavor and mixability
Legion Whey+ has built a reputation for some of the best flavors in the clean-label whey category. Mocha Cappuccino tastes like a proper coffee shop drink. Chocolate Peanut Butter is widely cited as the best in class. Birthday Cake delivers vanilla cake batter notes without being cloying. Salted Caramel is rich and balanced. The stevia + erythritol blend produces high sweetness with minimal aftertaste for most users (though some report mild stevia bitterness).
Promix flavors lean less sweet and more whole-food. Chocolate uses Dutch-processed cocoa and organic cane sugar, producing a rich but restrained flavor. Cinnamon Bun is the standout: real cinnamon and a proper bakery-shop taste profile. Iced Coffee uses real coffee bean concentrate plus organic cane sugar. Vanilla is real vanilla bean rather than chemical vanillin. Mixability is good in both brands. Legion has a slight edge with its instantization grind.
Verdict by goal
Which one should you buy?
If you are running a cut and want the cleanest possible isolate macros, plus you enjoy stevia-sweetened flavors, buy Legion Whey+. Mocha Cappuccino and Chocolate Peanut Butter are standout daily-drivers. Subscribe-and-save locks in $49.99 for the 2 lb tub, which is one of the best premium isolate values we track.
If you want US small-farm sourcing transparency, slightly higher protein per scoop, and you prefer organic cane sugar over stevia, buy Promix Original Whey. The 2.5 lb Chocolate or Cinnamon Bun bag at $54.99 subscribe gives you 32 servings of small-batch whey with a paper-trail you can verify.
If you cannot decide: buy Legion Mocha Cappuccino for daily cuts and Promix Cinnamon Bun for weekend pancakes and oatmeal. Total cost: about $100. Two distinct flavor experiences from two distinct sourcing philosophies.
Common questions about Legion vs Promix
Is Legion actually a "no proprietary blend" brand?
Yes. Legion publishes the full per-ingredient breakdown on every product label, including exact amounts of every active ingredient. The brand has built its reputation on this transparency, especially in the pre-workout and fat-burner categories where proprietary blends are common. Whey+ is straightforward (whey isolate plus flavor and sweetener) but the brand's overall transparency posture is industry-leading.
Why does Legion use Irish grass-fed dairy?
Ireland has some of the most consistent year-round grass-fed dairy in the world thanks to mild climate that supports pasture grazing about 320 days per year. Irish dairy cooperatives also have established export channels into the US supplement market. The grass-fed claim is more rigorous on Irish dairy than typical US dairy, which is one reason Legion chose this sourcing path despite higher cost.
Does Promix actually source from small farms or is it marketing?
Promix does name specific family farms on its website and publishes information about its supplier network. The brand's founder Albert Matheny has visited and documented these farms in marketing content. The "small family farm" claim is more substantive than typical commodity-dairy sourcing. Whether it justifies the price premium is a personal call.
Which has fewer additives?
Promix has the leaner ingredient panel. Original Whey contains: whey protein concentrate, organic cane sugar (in sweetened flavors), cocoa or vanilla, sea salt, sunflower lecithin. Five to six ingredients total. Legion Whey+ contains whey isolate, natural flavor, stevia, erythritol, sunflower lecithin, citric acid. Six to seven ingredients. Both are dramatically cleaner than mainstream whey but Promix is the slightly shorter label.
Are these brands safe for daily long-term use?
Yes. Both brands meet GMP standards, both run per-batch third-party testing, and both have multi-year track records of clean test results. Legion's Informed Choice certification adds an extra layer of banned-substance screening that matters for tested athletes. One to two scoops daily is well within standard protein-intake guidance.
Which one should I add to oatmeal vs use as a shake?
Promix is better for oatmeal due to its richer milk-like flavor and slight sweetness from cane sugar. Legion Whey+ is better for cold shakes due to its instantization and stevia sweetness intensity. If you primarily eat oatmeal with whey mixed in, lean Promix. If you drink shakes shaken with water and ice, lean Legion.