While protein powders for women are generally considered safe and effective, there are a few potential side effects to be aware of. The most common side effect is gastrointestinal discomfort, including bloating, gas, and diarrhoea. This can be alleviated by taking the powder with plenty of fluids and starting with a smaller dose. Other potential side effects include headaches, fatigue, and nausea. If you experience any of these side effects, stop taking the supplement and speak with a doctor.