ProMix Grass-Fed Micellar Casein, Unflavored Review
#7 of 8 · Best premium grass-fed✓ Label verified · Supplement Facts read Sep 7, 2026Real retailer photo, cut out. Label unedited.
Consider it. The premium grass-fed minimalist — cold-processed, additive-free casein, but no third-party seal. Cold-processed, acid-free micellar casein from pasture-raised cows, 25 g protein per serving (BCAA content not stated on the label), with no artificial sweeteners, gums or fillers.
$50$1.30 / serving
Why It Scores 7.8 — And The Label Line Behind Each Number
Form & purity (micellar)
30% of scoreIt's cold-processed, acid-free micellar casein — the acid-free processing is a genuine plus, since it avoids the harsher methods that produce faster-digesting caseinate — from grass-fed dairy, unflavored with just sunflower lecithin for mixing. That's a clean, minimally-processed form. It scores solidly rather than at the very top here because a few picks edge it on pure form specificity, but the additive-free, cold-processed micellar profile is exactly what this axis wants.
- Form
- Micellar casein (cold-processed, acid-free; grass-fed, pasture-raised)
- Sweetener
- None — unflavored single ingredient + sunflower lecithin for mixing
- Allergens
- Contains milk; soy-free (not lactose-free)
Protein per serving & macros
25% of scoreA strong axis: 25 g of protein per serving with low carbs and no added sugar — a lean, night-appropriate macro from a clean, additive-free base. It scores among the better protein/macro results in the lineup, reflecting a full 25 g dose with nothing diluting it. Two caveats: that 25 g comes from a 2-scoop serving, and the Supplement Facts panel doesn't break out a BCAA figure — an earlier version of this review cited 5.3 g of BCAAs, which isn't stated on the label, so we're not crediting a number we can't verify.
- Protein
- 25 g per serving (2 scoops); BCAA content not stated on the label
Third-party testing
20% of scoreThe honest read: ProMix makes disclosed clean-sourcing claims — soy-free, non-GMO, no added hormones, grass-fed — but carries no Informed Sport or NSF banned-substance seal. Those are manufacturer claims, not an independent certification, and we won't frame them as one. It scores below the certified picks on this axis for exactly that reason; if you need a verified seal, Naked (NSF) or the Informed Sport pair are the choices.
- Third-party testing
- None stated (brand claims soy-/GMO-/hormone-/filler-free; no Informed Sport/NSF seal)
Value per serving
15% of scoreAt about $50 for a 2.5 lb bag of ~39 servings, cost per serving lands near $1.30 — premium, driven by the grass-fed sourcing and cold processing. It's fair value for what it is, but on pure price per gram of protein it can't match Dymatize or the unflavored bulk bags. A reasonable but not standout value, consistent with a premium-sourcing product.
- Servings
- ~39 per 2.5 lb bag
- Value
- ~$50 / 2.5 lb bag ≈ $1.30 per serving
Taste & mixability
10% of scoreThe weak axis, as with all the unflavored picks: there's no flavor to rate and plain casein is bland and thick. The sunflower lecithin helps it mix better than raw casein, and it blends fine into oats, yogurt or a flavored smoothie, but on its own it's not something you'll enjoy drinking. Lowest weight, and the expected trade-off of an additive-free, unflavored powder.
- More Specs
- Carbs / sugar
- Low carb, no added sugar
Label verified. Every figure read from the Supplement Facts photo, Sep 7, 2026.
Marketing Claims Vs. Reality
Grass-fed, pasture-raised, cold-processed acid-free micellar casein.
These are disclosed sourcing and processing claims from the brand. Acid-free cold processing is genuinely relevant — it helps preserve the intact micellar structure rather than producing faster-digesting caseinate — but the grass-fed/pasture-raised sourcing isn't independently certified on the listing, so it's a credible manufacturer claim, not a verified seal.
Additive-free — no artificial sweeteners, gums or fillers.
The label is an unflavored single ingredient plus sunflower lecithin as a mixing aid, with no sweeteners, gums or fillers — a genuinely minimal, verifiable formula.
25 g of protein per serving.
The nutrition panel states 25 g protein per serving — accurate, with the honest note that it's a 2-scoop serving. The panel does not break out a BCAA figure, so we no longer cite a BCAA number for this product.
Soy-free, non-GMO, no added hormones.
Soy-free is consistent with the sunflower-lecithin formula. Non-GMO and no-added-hormones are disclosed supply claims from the brand; without an Informed Sport/NSF seal or a published third-party audit on the listing, they're credible manufacturer statements rather than independently certified facts.
Premium quality casein for muscle building.
It's a genuinely clean, well-sourced casein, so 'premium quality' is fair. But 'for muscle building' rests on general casein/protein evidence (Res 2012 pre-sleep MPS); grass-fed, cold-processed sourcing doesn't add hypertrophy over a well-made casein — total daily protein does that (Morton 2018).
What Our Test Actually Found
Correction: the label does not print a BCAA figure
An earlier version of this review said the label lists 5.3 g of BCAAs per serving. The Supplement Facts panel on this listing shows Calories, Total Fat, Cholesterol, Sodium, Total Carbohydrates and Protein (25 g) per 2-scoop serving — no separate BCAA line. We re-read the label on Sep 7, 2026 and corrected every mention of the 5.3 g BCAA figure to reflect that it is not stated on the label.
Grass-fed sourcing plus additive-free — the specific niche
ProMix fills a precise gap: you want grass-fed, pasture-raised dairy AND a fully additive-free label. It's cold-processed and acid-free (which helps keep the micellar structure intact), 25 g protein, no sweeteners or fillers, soy-free. If that combination is your priority, it's the strongest option for it in the lineup — Naked is the certified minimalist, ProMix is the grass-fed one.
Acid-free cold processing is a real, relevant detail
Unlike the marketing fluff on many tubs, the cold-processed, acid-free method matters here: acid or heat processing is what turns casein into faster-digesting caseinate, which defeats the slow-release purpose. Keeping it acid-free helps preserve the intact micellar form. It's one of the few processing claims on this page that connects to an actual functional property.
The certification gap is the honest cost of the sourcing story
ProMix leans on disclosed clean-sourcing claims — grass-fed, non-GMO, no added hormones — but carries no Informed Sport or NSF seal. Those are manufacturer statements, not independent certification. That's precisely why it sits a notch behind Naked (#6), which offers a similar additive-free profile plus an actual NSF seal. If verification matters more than grass-fed sourcing, Naked is the better call.
Premium price, unflavored format — plan for both
At about $1.30 a serving it's a premium buy, and it's unflavored, so it's bland and thick on its own. Consistent with quality-over-price, it earns its spot on sourcing and clean processing, not on cost. Blend it into oats or a flavored smoothie; don't expect to enjoy it plain. If you want grass-fed but flavored, Legion (#5) is the ready-to-drink alternative.
Full analysis: all pros & cons (6), buy if / skip if
- Grass-fed, pasture-raised micellar casein, cold-processed without acid
- Additive-free: no artificial sweeteners, gums or fillers; 25 g protein per serving
- Soy-free, non-GMO, no added hormones; ~39 servings in the 2.5 lb bag
- Acid-free processing helps preserve the intact, slow-release micellar structure
- Premium price per serving; unflavored only (needs your own flavoring)
- No Informed Sport / NSF certification — sourcing claims are disclosed but not independently certified; contains milk
- You want grass-fed, pasture-raised, cold-processed casein with no additives
- You flavor your own shakes and value a minimally-processed label
- You prefer sourcing story and clean processing over a certification
- You need a banned-substance certification — go Naked (#6, NSF) or NOW/Ascent (Informed Sport)
- You want a ready flavor or the lowest cost per gram — go Dymatize (#1) or a bulk bag
Cold-processed, acid-free micellar casein from pasture-raised cows, 25 g protein per serving (BCAA content not stated on the label), with no artificial sweeteners, gums or fillers. Soy-free, non-GMO, no added hormones. The catches: premium cost per serving, unflavored only, and no Informed Sport/NSF certification — the sourcing claims are disclosed but not independently certified. Best for purists who want grass-fed AND minimally processed and will flavor it themselves.
ProMix Casein is the premium grass-fed pick for purists who want sourcing and a clean label together. It's a cold-processed, acid-free micellar casein from pasture-raised cows, with no artificial sweeteners, gums or fillers, delivering 25 g of protein per serving (BCAA content isn't broken out on the label). It overlaps with Naked on the additive-free, unflavored philosophy but leans harder into the grass-fed, cold-processed story, and it's soy-free, non-GMO and made without added hormones. The catches are a premium price per serving, the unflavored-only format, and the lack of a formal banned-substance certification — the brand's clean-sourcing claims are disclosed but not third-party certified on the listing. If you specifically want grass-fed, minimally-processed casein and don't mind flavoring it yourself, it earns its spot, just a notch behind the certified minimalist above it.
The premium grass-fed minimalist — earns its place for the sourcing purist, a notch behind the certified pick.
ProMix Casein is the premium grass-fed pick for purists who want sourcing and a clean label together. It's a cold-processed, acid-free micellar casein from pasture-raised cows, with no artificial sweeteners, gums or fillers, delivering 25 g of protein per serving (BCAA content isn't broken out on the label). It overlaps with Naked on the additive-free philosophy but leans harder into the grass-fed, cold-processed story, and it's soy-free, non-GMO and made without added hormones. The catches are a premium price per serving, the unflavored-only format, and the lack of a formal banned-substance certification — the clean-sourcing claims are disclosed but not third-party certified. If verification matters more, Naked (#6) offers a similar profile plus a real NSF seal; if you want grass-fed but flavored, Legion (#5) is the pick. But if you specifically want grass-fed, minimally-processed casein and don't mind flavoring it yourself, this earns its spot, just behind the certified minimalist above it. (Dairy protein — low lactose, not lactose-free.)
If This Doesn’t Fit — Try These
06Naked Casein
Naked Casein is the minimalist's answer: a single ingredient — 100% micellar casein — with no sweeteners, flavors, gums, or fillers of any kind, and it's NSF Certified and independently tested, which is a real mark of quality.
05Legion Casein+
Legion Casein+ is the grass-fed, naturally-sweetened option for someone who wants a clean premium label but doesn't want to go fully unflavored.
01Dymatize Elite Casein
Dymatize Elite Casein is the best all-round pick because it nails the things that actually matter for casein: it's 100% micellar (the genuinely slow-digesting form), it's dosed at a full 25 g of protein for only about 130 calories, and at 50 servings a tub it's one of the better values here — all wrapped in a chocolate that's repeatedly rated among the smoothest-mixing caseins, which is no small thing for a notoriously thick protein.
Quick Answers
What does 'cold-processed, acid-free' actually mean for me?
It's one of the few processing claims that connects to a real property. Casein can be turned into faster-digesting calcium caseinate through acid or heat processing — which defeats the slow-release reason to buy casein. Keeping it cold-processed and acid-free helps preserve the intact micellar structure, so it clots and releases slowly as intended. It won't build more muscle, but it protects the kinetics you're paying for.
How is this different from Naked Casein?
They're close cousins — both single-ingredient, additive-free, unflavored micellar casein. The split is what each emphasizes: ProMix leans into grass-fed, pasture-raised, cold-processed sourcing but has no third-party seal; Naked is NSF Certified but conventional (still non-GMO, no rBGH/rBST). If grass-fed sourcing is your priority, ProMix; if an independent certification is, Naked. Both need you to flavor them yourself.
Is it worth the premium over the bulk bags?
Only if you specifically value grass-fed, cold-processed sourcing. At about $1.30 a serving it costs more than the unflavored bulk bags (BulkSupplements, NOW) for the same basic job — slow-release protein you flavor yourself. Consistent with quality-over-price, it earns its spot on sourcing, not cost. If grass-fed isn't a must, the cheaper unflavored bags give you the same slow-release protein for less.
Sources & Further Reading
3 peer-reviewed sources, each linked to PubMed
- [1] Res 2012 PMID 22330017 — Protein ingestion before sleep improves postexercise overnight recovery. Casein before sleep raised overnight muscle protein synthesis versus placebo — supporting a 25 g cold-processed micellar serving like ProMix's for the overnight window.
- [2] Boirie 1997 PMID 9405716 — Slow and fast dietary proteins differently modulate postprandial protein accretion. Casein produced a slow, prolonged amino-acid release and stronger suppression of protein breakdown than whey — the mechanistic reason acid-free cold processing (which preserves the intact micellar form) matters for a true slow release.
- [3] Morton 2018 PMID 28698222 — A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Training gains tracked total protein (~1.6 g/kg/day) with no clear source advantage — confirming grass-fed sourcing is a values/quality choice, not a muscle-growth upgrade.
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