Two of America's purest whey brands face off. Both source from small grass-fed dairies. Both refuse to use artificial sweeteners. The difference comes down to filtration (concentrate vs isolate), pricing structure and flavor strategy.
If you have eliminated mainstream brands (Optimum Nutrition, Dymatize, MuscleTech) because you do not want artificial sweeteners, artificial flavors, sucralose or proprietary blends, your shortlist gets short fast. Naked Nutrition and Promix Nutrition are the two American brands that consistently make it. Both publish full sourcing detail, both source from small family dairies, both lean into "fewer ingredients is better."
The most common mistake shoppers make: assuming they are buying the same product. They are not. Naked Whey is a whey concentrate; Promix's flagship is a whey isolate. The filtration difference shows up in the protein-by-weight ratio, the texture, the lactose content and the price.
| Metric | Naked Whey (5 lb, unflavored) | Promix Grass-Fed Whey Isolate (5 lb, vanilla) |
|---|---|---|
| Tub size | 2,268 g / 5 lb | 2,270 g / 5 lb |
| Servings per tub | 76 | 74 |
| Protein per serving | 25 g | 25 g |
| Serving size | 30 g | 30 g |
| Format | Whey concentrate | Whey isolate |
| Protein density by weight | ~83% | ~83% (isolate-filtered) |
| Number of ingredients | 1 (just whey) | 2–4 depending on flavor (whey, natural flavor, stevia) |
| Source | Grass-fed, hormone-free, rBGH-free dairies | Small family-farm grass-fed dairies |
| Sweetener | None (unflavored) or stevia (flavored) | Stevia + monk fruit |
| Artificial dyes | None | None |
| Lowest tracked price | $99.99 (Amazon) | $99.99 (Amazon) |
| Cost per serving | $1.32 | $1.35 |
| Cost per gram of protein | $0.053 | $0.054 |
| Best for | Baking, smoothies, mixing into food, unflavored use | Daily shakes, post-workout, taste-first clean-label drinkers |
| Smaller trial size | 1 lb at $24.99 | 2 lb at $49.99 |
The single biggest case for Naked Whey is unflavored. Most protein powders are essentially impossible to stir into oatmeal, pancake batter or yogurt because the sweeteners and flavoring turn everything into a confused dessert. Naked Whey unflavored is just whey. Stir 25 g into a bowl of plain Greek yogurt and you have a 40+ g protein snack that still tastes like Greek yogurt. Bake it into pancakes and you get protein pancakes that do not taste artificially sweetened.
The flavored Naked Whey options (chocolate, vanilla, strawberry) use a small amount of organic cocoa, vanilla and stevia for flavor. They are minimal but not as clean as the unflavored. If flavor matters to you, this is also where the price-per-gram increases slightly.
Promix's edge is the filtration. By using whey isolate instead of concentrate as the base, Promix delivers slightly tighter macros (lower lactose, lower fat per scoop) at the same price point. For lactose-sensitive lifters who still want clean-label sourcing, this is the more comfortable pick. The mouthfeel is also smoother: isolate mixes thinner and smoother than concentrate, which matters in a daily shake.
Promix flavor lineup includes Dutch Chocolate, French Vanilla, Vanilla Bean and seasonal rotations. The flavors lean closer to "natural" than "dessert"; expect a competent vanilla, not a "Vanilla Ice Cream" sugar bomb. Sweetened with stevia and monk fruit, no sucralose.
Both products price almost identically at the 5 lb size: roughly $99.99 on Amazon, $100–105 at iHerb, with a few dollars of variance at Vitacost and Walmart. The interesting pricing happens at smaller sizes. Naked Whey offers a 1 lb tub at $24.99, which is the cheapest way to trial premium grass-fed whey we have found. Promix's smallest size is typically a 2 lb tub around $49.99.
Naked Nutrition sells primarily through Amazon, iHerb and the NakedNutrition.com site, plus a presence on Vitacost and Walmart.com. Promix sells through Amazon, iHerb and Vitacost (plus PromixNutrition.com direct). Neither is widely available at brick-and-mortar GNC or Target, so you should expect to order online either way.
If you want the cleanest possible single-ingredient protein and you plan to use it in baking, oatmeal, yogurt or other unflavored applications: buy Naked Whey unflavored. The 1 lb starter tub at $24.99 is the smartest first purchase in this entire category.
If you want a clean-label flavored daily shake and you prefer the smoother texture of isolate: buy Promix Grass-Fed Whey Isolate in Dutch Chocolate or French Vanilla. The isolate filtration and slightly tighter macros are worth the marginal price difference.
If you are sensitive to lactose: Promix's isolate is the more comfortable pick. Naked Whey concentrate has more lactose by weight, which can bother some users despite the otherwise clean ingredient list.
If you are bulking and want a clean-label mass gainer: skip the head-to-head and grab Naked Mass at $99.99 for the 8 lb tub. There is nothing else in this clean-label category that matches the calorie density and ingredient simplicity.
Both publish sourcing detail and both source from grass-fed dairies. Naked Whey states its dairy comes from California family farms with grass-fed cows; Promix sources from a small network of US family farms with similar standards. Neither carries the USDA "100% Grass Fed" certification (which is rare and expensive to obtain), but both publish enough sourcing detail to verify the claim with reasonable confidence. If you require formal certification, Promix has been the more aggressive brand at publishing third-party verification documents.
Manufacturing and packaging overhead. The cost of producing and packaging a 1 lb tub is not five times cheaper than producing a 5 lb tub. Small-size protein tubs across every brand carry a 30–60% per-pound premium over large-size tubs. The 1 lb Naked Whey at $24.99 is a "trial size" priced for first-time buyers; the per-pound cost is intentionally higher to incentivize the bigger commitment.
Yes, but it will not dissolve fully into hot coffee like a typical protein coffee creamer. Naked Whey unflavored stirred into iced coffee, an iced latte or a blended coffee drink works well. Stirred into hot coffee, you will get a slight protein-precipitate texture as the heat changes the protein structure. For hot coffee specifically, a collagen peptide product (different protein, more heat-stable) is the better choice.
Promix sells several product tiers. The "Grass-Fed Whey Isolate" is the most common SKU we track and the one referenced throughout this comparison. The brand also sells a "Performance" formula with added ingredients and an unflavored version of the same isolate. The base protein source is the same; the difference is added flavoring and the marginal cost difference between SKUs.
Naked Whey unflavored, no contest. The lack of any flavoring or sweetener means it disappears into batter, dough or savory recipes. Promix's flavored isolates will color any baked recipe with the chocolate or vanilla note, which is fine for protein cookies but a problem for breads, pancakes and savory dishes. For baking specifically, the unflavored Naked Whey is the right pick across both brands.