Description
Rule One Source 7 Protein
22 grams of protein from seven sources — four whey fractions, micellar casein, milk protein isolate and pea protein — at 170 calories. Informed Choice certified, and built around taste and texture rather than lean macros.
That last part is the honest framing, and the label shows exactly why.
Run the numbers: 22g from a 41g scoop
That works out at roughly 54% protein by weight — noticeably lower than the 80% a pure isolate delivers.
That is not a flaw, but you should know what you are buying. The remaining weight is largely a cream blend — sunflower oil, maltodextrin, sodium caseinate, monoglycerides and mixed tocopherols — and that blend is precisely what produces the gelato-like texture the product is named for.
You are buying creaminess by weight. It is a deliberate formulation choice, and it explains the macros:
| Source 7 | A pure isolate | |
| Protein | 22g | 25g |
| Calories | 170 | 110 |
| Fat | 4.5g | 0g |
| Carbs | 10g | 1–3g |
| Protein by weight | ~54% | ~80% |
Sixty extra calories for a considerably better drinking experience. Whether that is worth it depends entirely on what you want the shake to do.
The seven sources, and what staged release actually means
The blend genuinely does span digestion rates, which is the coherent idea behind it:
- Hydrolysed whey — pre-broken into peptides, fastest
- Whey isolate and native whey isolate — fast
- Whey concentrate — fast to moderate
- Milk protein isolate — roughly 80% casein, 20% whey, so moderate to slow
- Micellar casein — slowest. Forms a gel in stomach acid and releases amino acids over several hours
- Pea protein — moderate, and the one non-dairy source
Native whey isolate is the interesting inclusion. Most whey is a by-product of cheesemaking; native whey is filtered directly from milk, which we explain fully on our PÜR NATIVE page. Seeing it in a blend at this price is unusual.
The casein is what makes this a genuinely different product from a whey powder. Casein clots in the stomach and releases slowly — which is why this suits before bed or a long gap between meals far better than it suits post-workout.
Honest note on the 22g
22 grams is on the lower side, and it matters more here than it would in a fast whey.
Muscle protein synthesis is triggered by reaching a leucine threshold, and a fast whey hits that quickly with a sharp amino acid spike. A predominantly slow-release blend delivers the same aminos more gradually, which is excellent for sustained supply and less ideal for maximally triggering that response from a single serving.
Practically: if you are using this post-training or as your main protein hit, consider a scoop and a half, or pair it with food. If you are using it before bed or between meals — which is what it is best at — 22g is perfectly appropriate.
Specs (per 41g scoop)
| Protein | 22g |
| Calories | 170 |
| Fat | 4.5g (1.5g saturated) |
| Carbohydrate | 10g, 1g fibre |
| Sodium | 280mg |
| Cholesterol | 90mg (30% DV) |
| EAAs | 10g+ naturally occurring |
| Certification | Informed Choice, tested by LGC |
| Sizes | 1.76 lb (20 servings), 3.96 lb (46), 5 lb |
| ⚠ Allergens | Milk and soy (soy lecithin) |
Two things to note. The 90mg cholesterol at 30% of daily value is high for a protein powder — worth knowing if you monitor it. And this contains soy, unlike most of our other proteins.
Blue spirulina and beta carotene appear as natural colourings rather than synthetic dyes, which is a small but genuine plus.
Where it fits on our shelf
| Source 7 | 22g / 170 cal | Creamiest. Staged release. Before bed or between meals |
| Rule One Casein | 25g / 110 cal | Pure slow release, far leaner |
| C4 Whey | 25g / 130–140 cal | Concentrate-led, flavour focused |
| CBUM Itholate | 25g / 110 cal | Pure isolate, leanest |
The honest guide: if you want slow-release protein without the calories, Rule One Casein gives you 25g at 110 calories. Source 7 is the one to choose when you want the shake to feel like a treat — a dessert substitute, an evening shake, something you look forward to.
How to mix it
- One scoop in 6 to 8 ounces of cold water or milk. Water is plenty creamy given the cream blend; milk makes it genuinely dessert-like.
- Blended with frozen banana or berries is where this product is at its best.
- Before bed or between meals, where the casein and milk protein isolate do their work.
- Not the ideal pre-workout shake — it is thick and sits heavily before heavy sets.
- Good for baking, since the casein content holds moisture where pure whey dries things out.
Who this is for
- Anyone who finds protein shakes a chore — this is the most enjoyable one we stock
- People wanting an evening or between-meals shake with sustained amino release
- Anyone using a shake as a dessert substitute
- Tested athletes, given Informed Choice certification
- People who want both fast and slow proteins without buying two tubs
- Anyone baking with protein
Who this is not for
If you are cutting and counting calories, this is not the one. 170 calories for 22g is well behind an isolate's 110 for 25g.
It contains soy — worth flagging since most of our proteins do not.
If you monitor cholesterol, 90mg at 30% DV is high for a protein powder.
If you want maximum protein per scoop, 22g is on the lower side. Consider a scoop and a half if this is your main serving.
Not vegan — six of the seven sources are dairy.
If you want it purely for post-workout, a fast isolate does that job better and leaner.
Stack it with: nothing. At 170 calories with 10g carbs it is already substantial.
Frequently asked questions
What are the seven protein sources?
Whey isolate, whey concentrate, hydrolysed whey, native whey isolate, micellar casein, milk protein isolate and pea protein.
Why does it have more calories than other proteins?
The formula includes a cream blend — sunflower oil, maltodextrin and sodium caseinate — which creates the gelato-like texture. That is roughly 60 extra calories bought as creaminess.
What does staged release mean?
The seven sources digest at different rates, from hydrolysed whey (fastest) through to micellar casein, which forms a gel in stomach acid and releases amino acids over several hours.
When should I take it?
Before bed or between meals, where the slow-release sources are most useful. A fast isolate suits post-workout better.
Is 22g enough?
For an evening or between-meals shake, yes. If it is your main protein serving or post-training, consider a scoop and a half or pairing it with food, since slow-release blends produce a more gradual amino rise.
Does it contain soy?
Yes, soy lecithin, along with milk. Most of our other proteins do not.
Is it tested for banned substances?
Yes — Informed Choice certified, regularly tested by LGC.
Can I bake with it?
Yes, and better than a pure whey. The casein content holds moisture where isolate dries baked goods out.