Whey and whey isolate comparison
Thorne Whey Protein Isolate vs Klean Athlete Klean Isolate
Klean Isolate scores higher on our standard, 99/100 to 82/100. It earns more points for label transparency (fully disclosed vs proprietary blend) and protein density (90% vs 70% protein by weight), while Thorne Whey Isolate earns more for verified label data (7 vs 6 of 7 label values). We could not verify a current price for Klean Isolate, so we can't compare cost.
Both are scored out of 100 against our published standard: protein density, third-party testing, label transparency, sugar, ingredient simplicity and verified label data. Every number below is from the manufacturer's label; last checked 2026-10-13.
Thorne
Whey Protein Isolate
Klean Athlete
Klean Isolate
Side by side
Per serving, from each label. Bold marks the better score, protein density, sugar and cost where the two differ. How we score
| Compared | Thorne Whey Isolate | Klean Isolate |
|---|---|---|
| Our score | 82/100 | 99/100 (better) |
| Protein density | 22 / 3070% of each scoop is protein | 30 / 30 (better)90% of each scoop is protein |
| Third-party testing | 25 / 25Lot-tested for banned substances | 25 / 25Lot-tested for banned substances |
| Label transparency | 10 / 20uses a proprietary blend | 20 / 20 (better)Fully disclosed formula, no amino spiking |
| Sugar | 10 / 102 g sugar per serving | 10 / 101 g sugar per serving |
| Ingredient simplicity | 10 / 10Natural flavors and sweeteners | 10 / 10Unflavored |
| Verified label data | 5 / 5 (better)7 of 7 label values verified | 4 / 56 of 7 label values verified |
| Type | Whey Isolate | Whey Isolate |
| Protein per serving | 21 g | 20 g |
| Serving size | 1 scoop (30.2 g) | 1 scoop (22.3 g) |
| Protein by weight | 70% | 90% (better) |
| Sugar | 2 g | 1 g (better) |
| Calories | 100 | 85 |
| Cost per 25 g protein | $2.58 | Not verified |
| Price per serving | $2.17 | Not verified |
| Third-party certifications | NSF Certified for Sport | NSF Certified for Sport |
| Sweeteners | Evaporated Cane Juice Sugar, Rebaudioside A (Stevia) | None listed |
| Allergens | Milk | Milk |
| Proprietary blend | Yes | No |
| Added free amino acids (amino spiking) | No | No |
| Last checked | 2026-10-13 | 2026-10-13 |
Which to choose
Only the differences in our records. A value we couldn't verify never counts as a difference.
Choose Thorne Whey Isolate if…
- You want a powder the brand labels soy-free (our record for Klean Isolate has no such label).
Choose Klean Isolate if…
- You want more of each scoop to be protein (90% vs 70% by weight).
- You want less sugar (1 g vs 2 g per serving).
- You want a fully disclosed formula (Thorne Whey Isolate uses a proprietary blend).
- You want no sweeteners (Thorne Whey Isolate uses evaporated cane juice sugar and rebaudioside a (stevia)).
- You want a powder the brand labels non-gmo (our record for Thorne Whey Isolate has no such label).
The two powders
Good to know
Labels and prices change, so check the package before buying, especially if you have allergies. If you are pregnant, nursing, buying for a child or managing a health condition, ask your doctor before adding a supplement.