There are no side effects, ever. Don't be silly
Merck & Co. faced numerous lawsuits related to Propecia, where internal company emails suggested that executives were aware of the potential for serious side effects like sexual dysfunction and depression, but did not adequately warn users. Specifically, these emails indicated that Merck knew about the high dropout rate in clinical trials due to these side effects but chose not to emphasize these risks in their marketing or warnings. This came to light especially around the time when Merck updated the drug's label in 2012 to include warnings about persistent sexual side effects, which was after many users had already experienced issues.