Best Clean Label Protein Powders in 2026
Comparing Levels Grass-Fed Whey, Momentous, Naked Nutrition, and Transparent Labs on ingredient transparency and third-party testing standards.
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Protein powder should be a simple product: protein, and maybe a flavor system. In practice, many popular protein powders pack in artificial sweeteners, gums, fillers, and undisclosed additive blends. Clean-label protein powders strip that back down, favoring short ingredient lists and independently verified purity.
This roundup compares four brands built around that philosophy: Levels Grass-Fed Whey, Momentous, Naked Nutrition, and Transparent Labs.
Why protein powder purity matters
Research on whey protein supplementation has consistently linked it, when combined with resistance training, to improvements in muscle mass and strength measures such as one-repetition-maximum strength, particularly in trained individuals (systematic review and meta-analysis on dietary protein supplementation and resistance training, British Journal of Sports Medicine). But those benefits come from the protein itself, not from any additional additives, which is part of why a minimalist ingredient list is worth prioritizing.
Because protein powders are consumed daily by many people, often in large volumes, contamination risk from heavy metals or undisclosed substances is a meaningful concern. Third-party testing programs like Informed Choice and NSF Certified for Sport are designed specifically to verify that a product's contents match its label and that it's free of banned substances (NSF Certified for Sport Program).
Top clean label protein powder picks
Levels Grass-Fed Whey
Levels Grass-Fed Whey keeps things minimalist: grass-fed, hormone-free dairy, natural sweeteners, and no fillers, artificial flavors, or added sugar. It's a strong pick for people who want the simplest possible whey protein formula.
Best for: people who want a straightforward grass-fed whey with the shortest possible additive list.
Momentous
Momentous has every batch NSF Certified for Sport, publishes Certificates of Analysis, and names the specific clinically studied forms of its ingredients. It contains no proprietary blends, which extends its transparency beyond just the protein source.
Best for: athletes and tested competitors who want NSF Certified for Sport assurance with fully disclosed, clinically studied ingredient forms.
Naked Nutrition
Naked Nutrition is built around radically short ingredient lists, with some products containing as little as one ingredient. It avoids artificial sweeteners and is Informed Choice tested, giving it both simplicity and third-party verification.
Best for: people who want the absolute shortest possible ingredient list combined with Informed Choice testing.
Transparent Labs
Transparent Labs offers full-disclosure sports supplements with published third-party test results and zero artificial sweeteners, colors, or preservatives across its lineup.
Best for: shoppers who want published third-party test results alongside a completely artificial-additive-free formula.
How these four compare
| Brand | Protein source focus | Sweeteners | Testing/certification |
|---|---|---|---|
| Levels Grass-Fed Whey | Grass-fed, hormone-free whey | Natural | No fillers or artificial flavors |
| Momentous | Named, clinically studied forms | Varies by product | NSF Certified for Sport every batch, published COAs |
| Naked Nutrition | Minimal, sometimes single-ingredient | No artificial sweeteners | Informed Choice tested |
| Transparent Labs | Full-disclosure sports formulas | Zero artificial sweeteners | Published third-party test results |
Protein supplementation may support muscle mass and strength gains when combined with resistance training, but it's not a substitute for adequate whole-food protein intake or a training program, and results vary based on total daily protein intake and training status (BJSM meta-analysis).
What to look for in a protein powder
Ingredient list length
The shorter the list, the fewer additives you're consuming alongside the protein itself. Naked Nutrition is a useful benchmark here.
Named, verified certifications
Look for Informed Choice, NSF Certified for Sport, or published third-party test results rather than a generic "tested for quality" claim.
Sweetener and additive disclosure
Even clean-label products vary in sweetener choice. If artificial sweeteners are a concern, check specifically for "no artificial sweeteners" language, as with Transparent Labs and Levels Grass-Fed Whey.
FAQ
How much protein do I actually need from supplements? Research suggests total daily protein intake around 1.6 g per kg of body weight is generally sufficient to maximize resistance-training-related gains in fat-free mass, with limited additional benefit beyond that threshold (BJSM meta-analysis). Whether that comes from food or supplements is a personal choice.
Is grass-fed whey nutritionally different from regular whey? Grass-fed sourcing, as used by Levels Grass-Fed Whey, speaks to how the source animals were raised and is often chosen for animal welfare or purity preferences, though the core amino acid profile of whey protein is broadly similar across sourcing methods.
What does Informed Choice testing verify? It's a third-party testing program that screens products for banned substances and verifies manufacturing quality, which Naked Nutrition carries across its tested products.
Are artificial sweeteners in protein powder a safety concern? This is a matter of personal preference and tolerance. Brands like Transparent Labs and Levels Grass-Fed Whey specifically avoid artificial sweeteners for shoppers who prefer to skip them.
Does NSF Certified for Sport matter if I'm not an athlete? It's not required for casual users, but it remains a strong general quality signal, since it involves batch testing for label accuracy and banned substances, as seen with Momentous.
Protein powders are often just one part of a broader supplement or training routine, and it's worth knowing how everything fits together, especially if you're also taking other supplements or peptides. The Cade app offers supplement and peptide interaction-checking and personalized tracking to help you manage your full routine with more confidence.
