Quick Picks
Eight products that made our shortlist after filtering across all 12 tracked US retailers. Click any pick to see live prices, all retailers, and the latest deal.
How We Ranked These
We restricted the pool to pure whey isolates, casein, and clear whey (categories where sugar is structurally lowest), then ranked by cost per gram of protein. All picks listed here have under 2g sugar per scoop in their primary flavors.
All prices verified within the last 24 hours. We re-check every product across all 12 tracked retailers (Walmart, Amazon, iHerb, GNC, Bodybuilding.com, Target, Vitacost, Muscle & Strength, Costco, Tiger Fitness, MyProtein, Transparent Labs) every two hours. Out-of-stock products are excluded from these rankings entirely.
Our Top Pick
5.5 lb · 24g protein/scoop · 83 servings
Pure whey isolate at the cheapest per-gram cost in the lowest-sugar bracket. 1g of sugar per scoop, 30g of protein, and a tub-price that beats every premium isolate by 30 to 50 percent. The value pick of the low-sugar tier. See MyProtein price →
Runner-Up
5 lb · 25g protein/scoop · 72 servings
Premium pure isolate from a clean-label specialist. 25g protein, under 1g sugar, more polished flavor than the value pick. See Amazon price →
Honorable Mentions
The next picks worth knowing about. Slightly different trade-offs but still in the top tier for this category.
Nutricost Casein Protein Powder. 5 lb, 24g protein/scoop, $41.79 at Vitacost.
Rule 1 Proteins R1 Whey Isolate. 5 lb, 25g protein/scoop, $49.99 at Amazon.
MyProtein Impact Whey Isolate. 5.5 lb, 25g protein/scoop, $54.99 at MyProtein.
Transparent Labs 100% Whey Protein Isolate. 5 lb, 28g protein/scoop, $59.99 at Transparent Labs.
See live prices on every whey isolate
Pure isolates dominate the low-sugar category. Browse the full whey isolate lineup.
Browse whey isolate →Frequently Asked Questions
Added sugars compete with your calorie and carb budget, especially on a cut or low-carb diet. A 5g sugar scoop drunk twice a day is 70 calories of pure sugar. Over a year, that's roughly 7 pounds of body fat if not offset elsewhere.
A small amount (1 to 2g per scoop) is naturally occurring lactose from whey. Anything above that is added (typically dextrose or maltodextrin) for taste and texture. Pure isolates contain virtually no lactose so they default to zero or near-zero sugar.
Not anymore. Modern stevia-sucralose blends produce flavors indistinguishable from low-sugar formulations of 5 years ago. Isopure Zero Carb and Dymatize ISO100 are widely considered among the best-tasting wheys on the market and have effectively zero sugar.
Yes, in normal doses. Erythritol is the most common in protein powders and is largely excreted unchanged. Maltitol is the exception (can spike blood glucose and cause GI distress). Most protein brands don't use maltitol; check the label if it matters.
No. Even sugar-free protein delivers calories from the protein itself (~4 calories per gram). A 25g protein scoop is ~110 calories regardless of sugar content. The 'zero' refers to carbohydrates and added sugars, not total calories.
Mostly. Per FDA rules, 'zero sugar' allows up to 0.5g per serving. So a product marketed as zero sugar may legally have 0.4g per scoop. For our rankings, we don't distinguish between true zero and below-0.5g; both qualify as effectively zero.
Related Rankings
Other useful price comparisons on ProteinPrice.com:
- The full best-value protein ranking across all 377 tracked products.
- Head-to-head product comparisons across our catalog.
- Browse whey isolate, the cleanest whey category by macros.
- Browse all whey protein blends, isolates, and concentrates.
- Casein protein for slow-release recovery and bedtime use.
- Plant protein from pea, rice, hemp, and soy blends.
- Mass gainers for hard gainers and calorie-surplus bulking.
- Protein bar comparisons across 70+ tracked bars.
- Ready-to-drink shakes and protein waters.
- Current protein deals live across all retailers.