There is no clear mechanism in the literature that says the peptide lowers libido. The signal has not been studied directly in a trial.

Libido is shaped by sleep, stress, hormones, body composition, body image, relationship context, other medications, and nutrition. Each of those moves during weight loss. Some shifts (lower visceral fat, better sleep, improved insulin signaling) tend to favor libido. Others (under-eating, micronutrient gaps, fatigue) push the other way.

A 2024 systematic review on GLP-1 and reward-system pathways found the peptides affect motivation and craving, but the review covered food and substance use, not sexual function specifically.