Across 305 first-hand reports, people mentioned a side effect 19 times (about 6 per 100 reports). The most common: stomach issues, acne, constipation. User reports show what people notice — they can't tell you whether Whey Protein is safe for you.
“I do notice they help significantly but i cannot tolerate them (yes, I have tried concentrate, isolate and hydro), I start to bloat a lot and feel a bit nauseous.”
“Just left the dermatologist and she said stop using whey protein as it's making my acne worse”
“The other thing I was going to get is a good pea protein for shakes (whey protein fucks me up).”
“I decided to start taking a scoop of whey protein everyday...I've also recently become heavily constipated.”
“DAE get constipation issues when you drink whey protein? I have been drinking SNI Pro Whey Pw-30.”
Conclusion: Analysis revealed that chronic and without professional guidance use of whey protein supplementation may cause some adverse effects specially on kidney and liver function. Presented data support a need for future studies co-relating the use of different types of whey protein with and without exercise to better see the impact on human physical health.