According to Dr. Anna Fleytman-Pope, D.O., board-certified in emergency medicine and a fellow of integrative medicine from Opt Health, estrogen plays a crucial role in our body’s immunity, growth, and repair processes. “When estrogen levels are low, it can weaken the immune function and potentially reduce the frequency of autoimmune issues,” she says. “Moreover, low estrogen levels can also decrease sexual interest, lead to depression, cause painful intercourse, and make individuals more insulin-resistant.”