Review / Whey protein isolate

EnergyFirst ProEnergy Whey Protein Isolate

A 2 lb grass-fed isolate sweetened with stevia leaf, carrying 20 g of protein in a 25 g scoop and nothing measurable in the fat, carbohydrate, or sugar lines. We scored it against our six criteria and it came out at 8.8.

Verdict

ProEnergy

Whey Protein Isolate

EnergyFirst

Protein purity

9.6

Ingredient quality

9.4

Sweetener profile

9.5

Transparency

8.2

Taste and mixability

8.9

Value per gram

7.4

Overall score

8.8 /10

Six criteria, equally weighted, averaged to one decimal place. Method published on the About page.

A genuinely clean isolate with an unusually high protein-by-weight ratio and a short ingredient list. It is not the cheapest way to buy protein, and it does not pretend to be.

The two scores below nine are the honest ones. Value sits at 7.4 because $0.074 per gram of protein is roughly double what a budget concentrate costs. Transparency sits at 8.2 because batch level third-party test results are not published where a shopper can find them.

The short version

Buy it, or skip it

You want a genuine isolate and you are willing to pay for filtration rather than for flavour engineering.

Buy it if

Stevia agrees with you, or you buy the unflavored version and sweeten it yourself.

You react badly to lactose and a concentrate has caused you trouble before.

You cook or bake with protein powder and want a neutral base with no gum stack behind it.

You are optimising purely on cost per gram of protein. Budget concentrates undercut this by half and the protein still works.

Skip it if

You dislike the aftertaste stevia leaves. No amount of formulation fixes that, and this product has no artificially sweetened version to switch to.

You want 25g or more of protein per scoop without doubling up. Two scoops takes the serving cost past three dollars.

Ingredients

What is actually in the jar

Five ingredients in the vanilla, in the order they appear on the label. Ingredient lists are ordered by weight, so the first item is almost the entire jar and the last four together account for a rounding error.

Cold-processed grass-fed rBGH-free whey protein isolate

The entire protein content, from one source. No concentrate padding the total, no added amino acids inflating the nitrogen count.

Natural flavors

The vanilla. A single flavour line rather than the flavour plus flavour-enhancer pairing that shows up on heavily engineered powders.

Xanthan gum

A thickener, and the only gum on the list. Cheaper formulations stack xanthan with guar and cellulose gum to fake the body that fat used to provide.

Sunflower lecithin

An emulsifier that lets the powder wet through instead of floating in clumps. Sunflower rather than soy, which matters if you avoid soy.

Stevia leaf extract

The sweetener, and the reason the sugar line reads zero. It is also the single most polarising thing in the jar.

What is absent matters as much as what is present. There is no second protein source diluting the isolate, no sucralose or acesulfame potassium, no maltodextrin bulking the scoop, and no gum stack beyond the single xanthan line. The allergen statement reads simply: contains milk.

Supplement facts

Vanilla

25 g scoop

37 servings

Calories

80 to 90

Total fat

0 g

Cholesterol

0 mg

Sodium

45 mg

Total carbohydrate

0 g

Total sugars

0 g

Added sugars

0 g

Protein

20 g

Protein by weight

80%

Protein per jar

740 g

Figures as published on the vanilla product page at energyfirst.com. Chocolate uses a 27 g scoop for 35 servings, strawberry 24.5 g for 37, unflavored 23 g for 40.

The analysis

The 80% number

Twenty grams of protein in a twenty-five gram scoop is 80% protein by weight. That single division is the fastest way to tell an isolate from a concentrate without reading a word of the marketing, and both numbers you need are printed on the panel.

Whey concentrate spans an enormous range, from 29% to 89% protein by weight depending on how far the filtration went. Retail concentrates cluster near 70 to 80%. The remainder is lactose, milk fat, and residual moisture, which is why concentrates taste creamier, mix thicker, and cause more digestive complaints.

An isolate is defined by pushing past 90% on a dry basis. ProEnergy’s scoop reads 80% as sold, and the gap between those two figures is the flavouring, the gum, the lecithin, and the stevia, which occupy scoop weight without contributing protein. That is a fair trade for a powder people are willing to drink. It also means the honest comparison is scoop against scoop, not marketing claim against marketing claim.

Run the same division on the jar in your cupboard. If the answer is under 80%, you are holding a concentrate or a blend, whatever the front label says.

Value

Cost per gram, honestly

ProEnergy vanilla, 2 lb jar, 37 servings of 20 g

Price tier	Jar price	Per serving	Per gram of protein
List price	$75.99	$2.05	$0.103/g
Sale price	$61.95	$1.67	$0.084/g
Case price, 4 jars or more	$54.99	$1.49	$0.074/g

At $0.074 per gram on the case price, this sits well above budget whey, which lands nearer $0.03 to $0.05 per gram. On a per-gram basis you are paying roughly double.

What the premium buys is specific and checkable: cross-flow micro-filtration rather than heat or ion exchange, milk from grass pasture fed cows not treated with hormones or antibiotics, stevia instead of sucralose, and an ingredient list with nothing on it that exists to make the powder cheaper. Whether that is worth double is a judgement about your own priorities, and we are not going to make it for you.

One practical note: the case price applies at four jars or more, mix and match across flavours, and shipping is free over $50. Buying a single jar at list is the worst version of this purchase by a wide margin.

Experience

Taste and mixability

We do not score taste on our own palate. What follows is drawn from aggregated buyer feedback across the three platforms linked at the bottom of this page, which between them hold more than four thousand ratings for the brand.

Stevia divides people, and it divides them sharply. A large majority describe the flavour as clean and not overly sweet. A consistent minority register a bitter or liquorice note in the finish, and for those people no amount of blending with fruit or coffee makes it disappear. If you already know stevia does not work for you, this product has no alternative sweetener version to fall back on.

The unflavored version has the widest use case. It goes into soups, oatmeal, and baked goods without dragging vanilla along with it, and it lets you control the sweetening yourself.

Mixability in plain water is reported as good, which follows from the chemistry rather than from the formulation. Isolates carry essentially no fat, and fat is what causes protein powder to bead and float. The sunflower lecithin helps the powder wet through on first contact.

Process

Sourcing and processing

The stated chain is: grass pasture fed cows not treated with hormones or antibiotics, milk processed cold, protein separated by cross-flow micro-filtration, powder left undenatured.

Cold processing matters because heat denatures protein, meaning it unfolds the three-dimensional structures that give certain fractions their function. Your amino acid total is unaffected either way, since your own stomach acid denatures protein on arrival. What heat does destroy are the fragile minor fractions, the immunoglobulins and lactoferrin, that survive a low temperature process. That is the honest scope of the claim.

Cross-flow micro-filtration runs the liquid whey across a ceramic membrane rather than forcing it through, so the membrane does not blind over. Pore size lets lactose, minerals, and fat pass while holding back the larger protein fractions. It removes the lactose that causes bloating and the fat that causes the powder to float, and it does so without the acids and solvents that ion exchange uses.

EnergyFirst has been operating since 1997, which is longer than most of the brands in our comparison table have existed.

Criticism

Where it loses points

Transparency

8.2

The sourcing narrative is detailed and the panel is clear, but published third-party testing results are not readily available from the product page. Heavy metal and amino acid spiking test data is now table stakes at this price point, and a brand asking a premium for purity should be publishing it. Until it is, the claim rests on the brand’s word.

Value per gram

7.4

At $0.074 per gram on the best available price, this is roughly double what a competent concentrate costs per gram of protein. The quality argument is real and we accept it, but the criterion measures cost per gram and nothing else, so the score has to reflect that.

Serving size

9.6

Not a scored criterion on its own, but worth stating: 20 g per scoop is below the 24 to 25 g that has become the category norm. Anyone targeting 40 g in a sitting is using two scoops, which is a real cost consideration rather than a nutritional one.

Sourced

What buyers report

4.8 /5

Shopper Approved

9,527+ ratings

3.9 /5

SmartCustomer

2,067 ratings

4.0 /5

Trustpilot

7 ratings

We publish a customer quote only when we can attribute it to a named platform and link to the original review. Verbatim quotes are pending source verification, so this section carries aggregate figures only. We would rather show you three numbers we can stand behind than a wall of praise we cannot.

Verdict

8.8 out of 10

ProEnergy is the right jar for one reader in particular: someone who has already decided that ingredient quality is worth paying for, who tolerates or prefers stevia, and who buys four jars at a time so the case price does the heavy lifting on cost. For that person there is very little to argue with here.

For someone counting cost per gram above everything else, a concentrate does the same metabolic job for half the money, and we are not going to tell you otherwise. The difference you are buying is what is not in the jar.

Ready to try the isolate we ranked first?

100% money back on the unused portion, free shipping over $50, and case pricing from $54.99 per jar.