It could impact muscle mass and performance

While the pill may sustain your performance throughout the month, some research suggests that your overall output may be lower than if you had a natural cycle. The same 2020 paper found that “when compared with a natural menstrual cycle, oral contraceptive pill use might result in slightly inferior exercise performance.”

Researchers concluded that this was because using hormonal contraception reduces hormone levels to similar levels experienced during the early follicular phase of a natural cycle – when you have low levels of oestrogen and progesterone. “This chronic downregulation might be responsible for the slightly impaired exercise performance demonstrated in [contraceptive pill] users when compared with their naturally menstruating counterparts,” researchers wrote.

A 2021 paper from the Journal of Strength and Conditioning also found that oral contraceptive users experienced diminished lean mass gains in response to 10 weeks resistance exercise training. They also and had lower anabolic (muscle building) hormones and higher catabolic (muscle-burning) hormone concentrations.

The pill: everything you need to know about exercising on hormonal contraception