Excess body hair and sometimes chest pain, fast heartbeat, weight gain, insomnia, swelling and several others. Rarely it can cause swelling around the heart (like 3% of users).
“The risk of ejaculation disorders was 8 times higher with finasteride versus dutasteride, and the risk of erectile dysfunction and decreased libido was 5 times higher (P = .001).”
https://www.urologytimes.com/view/real-world-5-ari-data-show-increased-sexual-side-effects-with-finasteride-vs-dutasteride