Is it safe to take whey protein every day?

A meta-analysis of 28 trials found higher-protein diets did not worsen kidney function in healthy adults, and a 30-day trial at roughly 80 g a day of whey — well above a single serving — found no adverse change in kidney, liver or metabolic markers in healthy men. Both exclude people who already have kidney disease, who should ask a doctor before adding daily protein supplementation.

What the kidney-safety research found

A systematic review and meta-analysis of 28 randomised controlled trials (1,358 participants) compared higher-protein diets (at least 1.5 g/kg bodyweight/day, or at least 100 g/day) against normal or lower-protein diets in adults without existing kidney disease. Higher protein intake did not worsen the change in kidney function, measured by GFR, compared with the lower-protein groups. That's a finding about total dietary protein from various sources, not one product's specific dose, but it directly addresses the most common daily-safety worry about protein intake.

A 30-day trial at a dose well above ours

A double-blind, randomised 30-day trial in 40 healthy, resistance-trained men had participants take two 40 g doses of whey protein a day — about 80 g/day total, roughly 3.6 times our 22 g serving — and measured general health, metabolic, hepato-renal and cardiovascular markers throughout. The whey-alone group showed no adverse change in any of those markers over the 30 days. If a dose well above what our label directs showed no adverse signal in healthy trained men over a month, that's a reasonable data point for daily use at our smaller serving, though it's still not a trial of our specific product.

How much protein a day is actually recommended

The 2017 International Society of Sports Nutrition position stand on protein describes 1.4-2.0 g of total daily protein per kilogram of bodyweight as sufficient for most exercising adults building or maintaining muscle, with higher intakes (2.3-3.1 g/kg/day) studied specifically for preserving lean mass during a calorie deficit. That's a range for your whole day's protein from all sources, not a recommendation to take our product a specific number of times — see how much whey protein to take a day for how our 22 g serving fits into a daily total.

The exception both studies make

Both studies above are specific to people without pre-existing kidney disease. If you have kidney disease, or a condition affecting kidney function, ask a doctor before adding daily protein supplementation of any kind — that caution isn't a footnote, it's the boundary of what these studies actually cover.

Our label's own caution

Our label directs anyone pregnant, nursing, under 18, or living with a medical condition to consult a physician before use — standard label caution, not a claim about what happens if someone in those groups takes it, since the safety research above was done in healthy adults.

Questions people ask

Is whey protein safe?

The research above, in healthy adults without kidney disease, doesn't show a kidney, liver or metabolic harm signal from higher protein intake, including a 30-day trial at a dose well above our serving. That's a conclusion about the research generally, not a claim specific to our tub.

Should I take whey protein every day?

Our label's directions are for one daily serving, and the safety research above was built on daily or near-daily supplementation over 30 days. Daily use is what's actually been studied at doses at and above ours.

Are whey protein powders safe long term?

The longest controlled trial we cite here ran 30 days. We didn't find a multi-year controlled trial of whey protein supplementation specifically; the kidney-function meta-analysis above pools trials of varying, generally shorter lengths. That's the honest boundary of what's been directly studied.

Is whey protein safe for kidneys?

The meta-analysis above found no adverse kidney-function change from higher-protein diets in people without existing kidney disease. It specifically doesn't extend to people who already have kidney disease — see who should not take whey protein for that group.