Multi Protein — Low Carb 4-Protein Blend
The protein that moves your Muscle number — 24 g per serving, blended fast-to-slow so the amino acids keep arriving for hours, not minutes.†
- 24 g protein, 11 g essential amino acids per serving†
- Fast, moderate, and slow proteins for sustained amino-acid delivery†
- Supports muscle protein synthesis alongside resistance training†
- Keeps you fuller longer than a fast whey alone†
What you can expect — and what was actually studied.
Each card is scoped to an endpoint where controlled trials found an effect. If it isn't here, we don't claim it.
More lean mass from the same training
Adding protein to a resistance program increased fat-free mass and strength across the pooled trials.†
Amino acids for hours, not minutes
Whey spikes and fades within about two hours; casein holds a plateau for six or more. This blend contains both.†
Fuller between meals
Protein is the most satiating macronutrient per calorie, and slow-digesting casein extends the effect.†
A full serving that clears the bar
In adults over 60, milk-protein doses of 22 g or more were needed before strength gains appeared. This serving is 24 g.
What to expect, and when.
Protein doesn't work like a pill. Nothing "kicks in." What changes is whether you hit your daily target every day — and the muscle trials that found an effect ran at least six weeks. Here is the honest clock.
Fuller, sooner
The satiety effect is immediate. Most people notice the gap between shakes and snacks widens the first week.
Hitting the target
This is the real job — closing the gap to your Protein Playbook number every single day. Recovery between sessions usually improves once intake is consistent.
The studied window
The resistance-training trials in the meta-analysis lasted six weeks or longer. Lean mass changes show up here, on a tape and a scale, not in a mirror.
Your Muscle number
At the Gauntlet, the arm and thigh measures tell you whether it worked. Protein plus load moved them, or it didn't.
Muscle is built between sessions — from amino acids that have to be there.
Training creates the signal. Protein supplies the material. After 40, two things make the material harder to come by: you need more of it per meal to trigger the same response, and most adults simply don't eat enough. A blend solves a third problem — timing.
- Anabolic resistance is real. Older muscle needs a bigger protein dose per meal to switch on synthesis. That's why serving size matters more at 55 than at 25.
- Fast and slow proteins do different jobs. Whey drives a sharp, short rise in synthesis. Casein holds amino acids in the blood for hours and cuts protein breakdown. This blend carries both, plus two proteins in between.
- The daily total is the number that counts. The meta-analysis found gains tracked total daily intake, up to roughly 1.6 g per kg of body weight. One serving is a quarter of that for most people.
5 ingredients. Here's the case for each.
Every active on the shelf gets the same five questions. Supplement Facts is below — that's the label. This is the argument.
Whey Protein Isolate
- Clinical dose
- Protein doses in the pooled trials ranged widely; what mattered was total daily intake reaching ~1.6 g/kg. Isolate delivers the highest protein-per-calorie of the four.
- What it does
- The fast fraction — amino acids peak in the blood within about an hour and drive a sharp rise in muscle protein synthesis.†
- Why this form
- Isolate is whey with most of the lactose and fat removed — more protein per scoop, easier on people who don't tolerate concentrate.
- Why this source
- BioTrust states grass-fed sourcing and third-party testing for purity and potency. Those are the manufacturer's statements; we haven't independently tested this lot.
- Evidence
- Boirie 1997 (kinetics); Morton 2018 (training outcomes).
Whey Protein Concentrate
- What it does
- Fast protein with more of the native milk fractions retained.†
- Why this form
- Concentrate keeps bioactive fractions that isolation strips out. BioTrust cites immune-supportive fractions; we list it as what it is — less-processed whey.
- Why this source
- Manufacturer's sourcing statements apply, as above.
- Evidence
- Same kinetics as isolate.
Micellar Casein
- What it does
- The slow fraction — forms a clot in the stomach, releasing amino acids over six-plus hours and reducing protein breakdown by about a third in the landmark study.†
- Why this form
- Micellar (not hydrolyzed) casein is the form that produces the slow plateau. Hydrolyzed casein digests fast and loses the point.
- Why this source
- Manufacturer's sourcing statements apply, as above.
- Evidence
- Boirie 1997: whole-body protein breakdown inhibited 34% after casein, not after whey.
Milk Protein Isolate
- What it does
- Milk's natural ratio — roughly 80% casein, 20% whey — in one ingredient. Moderate digestion speed.†
- Why this form
- It's the middle of the release curve. With isolate at the fast end and casein at the slow end, this fills the gap.
- Evidence
- Kinetics per Boirie 1997; older-adult milk-protein dosing per the 2021 meta-analysis.
ProHydrolase®
- What it does
- A digestive enzyme blend BioTrust states improves protein breakdown and amino-acid absorption.
- Why this form
- Manufacturer's choice. The supporting studies are small and industry-funded; we present it as BioTrust's claim, not ours.
- Evidence
- Manufacturer-attributed. Not counted toward the Shelf standard.
Supplement Facts — the label ▾
Supplement Facts
| Amount Per Serving | % DV | |
| Calories | 150 | |
| Total Fat | [VERIFY] g | [VERIFY]% |
| Total Carbohydrate | [VERIFY] g | [VERIFY]% |
| Dietary Fiber | 4 g | [VERIFY]% |
| Protein | 24 g | [VERIFY]% |
What the studies show. And where they don't.
Meta-analyses only — pooled results across many trials, not one flattering study. Links go to the papers.
Muscle mass and strength with training
Protein supplementation on top of resistance training added fat-free mass (+0.30 kg) and one-rep max (+2.5 kg) versus training alone. Gains tracked total daily intake up to ~1.6 g/kg.
British Journal of Sports Medicine, 2018 →Fast vs. slow protein
The study that coined "fast" and "slow" proteins: whey produced a sharp two-hour rise; casein a moderate plateau over seven hours, with protein breakdown cut 34%. The physiological case for a blend.
PNAS, 1997 →Dose in older adults
In adults 60 and over, milk-protein supplements improved strength only at doses of 22 g or more per serving. Lower doses did not. This serving is 24 g.
Nutrients, 2021 →Where the effect shrinks
The benefit of added protein got smaller with age in the pooled data, and was larger in already-trained people. Translation: after 50, protein helps less if the training isn't there. It is a supplement to load, not a substitute for it.
Morton et al., 2018 — age covariate →What it will not do
It will not build muscle without resistance training — the trials that found an effect added protein to a lifting program, not to a couch. It will not "boost metabolism" in any way you could measure; that's a marketing phrase, not an endpoint. It will not replace food: it's for the days your meals come up short of the Playbook target. And if you already eat 1.6 g/kg of protein from food, the research suggests adding more does very little.
Against what you'd otherwise buy.
| This blend | Plain whey isolate | "Lean" / diet protein | |
|---|---|---|---|
| Protein per serving | 24 g, 11 g EAAs | 20–25 g | Often 15–20 g |
| Release profile | Fast + moderate + slow | Fast only (~2 hrs) | Fast only |
| Casein (the slow fraction) | Yes — micellar | No | Rarely |
| Net carbs | 4 g | 1–3 g | Varies; check for fillers |
| Satiety | Extended, from casein | Short | Often relies on added fiber or stimulants |
| Clears the 22 g older-adult threshold | Yes | Usually | Often no |
Reviews arrive with the first cohort.
No reviews are shown until they're real. Second Prime members re-test their four numbers every 90 days; reviews here will come from people whose numbers we can see.
How to use it.
2 scoops in 8 oz
Water or milk. Shake or blend; two ice cubes helps. Drink within 10 minutes of mixing — it thickens.
Whenever the day is short
Timing matters less than total. Use it to close the gap to your Playbook number — after training, as a lunch that isn't happening, or before bed for the casein.
Every day you're under target
The trials measured daily totals over 6+ weeks. A shake three days a week won't move the tape.
Five tests before anything reaches the shelf.
Every product's scorecard is public.
Meta-analytic evidence for the category
Protein + training: 49 RCTs. Fast/slow kinetics: landmark 1997 trial. Dose threshold in older adults: 17 RCTs.
Clears the studied dose
24 g per serving; older-adult strength gains appeared at ≥22 g.
Full label transparency
Blend amounts per protein are not disclosed on the page. [VERIFY on label — if the panel lists a protein-blend total only, keep Conditional.]
Third-party testing
BioTrust states third-party testing for purity and potency. No certificate is published on the product page; we have not seen a lot-specific CoA.
Asked before buying.
I'm over 50. Does one serving actually do anything?
It clears the bar that the older-adult research set — 22 g of milk protein per serving — with 24 g. What it can't do is replace training. In the pooled trials, protein helped less with age unless the lifting was there.
Whey, casein, or a blend?
Whey is fast and short; casein is slow and long. Whey right after training and casein before bed each have evidence. A blend is the pragmatic choice for someone using one product to close a daily gap at whatever hour the gap shows up.
Does it have caffeine or stimulants?
No.
Allergens?
Contains milk. Made in a facility that also processes eggs, fish, tree nuts, peanuts, wheat, and soy. The label for your flavor governs.
Why does the Milk Chocolate / Café Mocha say "Prop 65"?
California requires a warning on those two flavors for lead exposure above the state's threshold, which is stricter than federal limits and common in cocoa-containing products. The other four flavors carry no warning. If it matters to you, choose one of those.
Can I cook with it?
Yes — smoothies, yogurt, oats, pudding. Heat is fine; it's already-denatured milk protein. It doesn't change the numbers.
What's the subscription commitment?
None. Ships on your schedule at the subscribe price. Pause, skip, or cancel from your account in one click — no email, no retention scripts.
The first dollar on the Shelf. For a reason.
Nothing else here moves the Muscle number if the protein isn't there. Close the gap every day for twelve weeks, then measure.
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Second Prime provides fitness education and coaching; it does not provide medical advice. Consult your physician before starting any supplement, especially if you take prescription medication. Results vary. Product claims are the manufacturer's.