I was diagnosed with a prolactinoma in may of this year. I requested blood work because of NO libido, and the list I went in with after researching included prolactin. I had a 3mm prolactinoma. Started cabergoline at 0.5mg a week. I was frustrated with having absolutely no libido so I took a second 0.5mg 2 days after my first. Two days later my libido was stronger than ever. That lasted about 3 days, then it disappeared again. I was suffering from bipolar symptoms because of the high dose of meds so I decided to stick with the doctors recommended dosing. I thought the whole time that my prolactin was still high, and that the brief period of having a libido was because I took so much cabergoline. My next blood work came in and my prolactin was so low there was no reading. The doctor advised I take 0.25mg a week. I did this for a couple weeks and still had no libido. Being a stubborn prick, I stopped taking the meds all together. I haven't taken it for about 3 weeks. My latest lab work just came in and my prolactin is at 1ng/dL or whatever the units are. It's still off the scale. My libido came back a little bit having stopped. My theory is that having extremely low prolactin will kill libido. What about other factors??? Well my testosterone is at a 900. Everything else was tested and is normal. Thyroid is fine. Prolactin seems to be the culprit. I assume this is groundbreaking since Ive done hours and hours of searching and asking multiple doctors whom all said that low prolactin should not reduce libido... it is only the case when prolactin is high. The real results will come with my prolactin is normal again. I don't know why it hasn't increased by much.