Is a new weight-loss drug making people fall out of love? | Weight-loss drugs

A recent TikTok video shows a man wearing a black baseball cap, with text on the video reading: “strange effects from Reta” and “ruined relationships.”

He’s referring to retatrutide, an experimental weight-loss drug that targets three appetite-related hormones. It is still in clinical trials but has generated so much interest that some users are already obtaining it illegally online before its approval. The “weird theory going around,” the TikTok poster says, is that drugs can “make you fall in love.”

Below the video, the comments are filled with accounts of what users describe as emotional flattening. One person says the drug “also stopped food cravings and lust,” another says she suffers from “severe anhedonia.” [the inability to experience joy or pleasure]”, and a third says that retatrutide made them feel “indifferent to 99% of everything”.

This is part of several viral videos asking if peptides are stopping you from falling in love. Although it seems strange, medical researchers are beginning to study whether these drugs act as a “general reward buffer.” Because they target the brain’s reward center, the mesolimbic system, they apparently stop not only the “noise of food” but also, inadvertently, the quiet joy found elsewhere.

Although retatrutide is the newest and most potent, reports of “emotional flatness” have also surfaced among users of approved GLP-1 drugs, such as Mounjaro. A recent case report suggests that these medications may influence brain regions involved in emotional regulation and potentially trigger or worsen severe depressive symptoms.

Academic neuroscientist Paul Kenny, of the Icahn School of Medicine at Mount Sinai, New York, said the world was in the middle of a “huge experiment” as millions of people began using GLP-1 drugs, and researchers were only now beginning to collect data on how they affect behavior as well as physiology.

He said some of the links already emerging were surprising, suggesting the drugs could influence much more than appetite and weight. “We still know very little about how GLP-1 works in the brain,” he said, although new research suggests the drugs may help protect against neurodegenerative disorders. Recent clinical trials in people in the early stages of dementia have raised the possibility that drugs that enhance GLP-1 signaling could have neuroprotective effects.

As for whether such drugs might impair love, emotions or social connections, Kenny was more cautious, saying he couldn’t comment directly from a neurobiological perspective. But he said it wouldn’t surprise him if drugs so closely linked to the body’s energy systems also shape human emotions and social interactions.

“A lot of animal behavior is influenced by energy and energy availability, everything related to survival,” he said. Since GLP-1 is intimately linked to energy status, he said, it was plausible that shifting these signals could also change behavior.

In animals, for example, Kenny said territoriality often increased when food was scarce, suggesting that energy balance may shape the nature of social interactions. “GLP-1 is also linked to how the brain processes rewards and pleasant stimuli,” he said.

These medications affect libido, as Dr Naveed Asif, GP at London General Practice, explains: “From a physical perspective, GLP-1 medications affect smooth muscle activity, which can influence arousal and orgasm due to changes in blood flow to the genital area.

“Chemically, the effects may vary among different patient groups, but there is also a dopaminergic component: dopamine, a hormone released in the brain in response to stimuli, may decrease when using these peptides. This creates challenges related to sexual desire and attraction, which can impact overall sexual function.”

He adds: “Estrogen is a key sex hormone, so taking GLP-1 can disrupt its balance, which can lead to emotional disturbances. This problem appears to be more pronounced in women using these peptides.”

“I have observed that many women experience significant side effects that cause them to stop treatment. Some patients have reported worsening mental health, including increased depression and anxiety, which likely affects sexual function as a secondary consequence.”

Dr Sophie Dix, of online pharmacy MedExpress, said that “the move from ‘reduced cravings’ to ‘inability to fall in love’ is an area where science is currently not keeping up. Romantic attachment is a much more complex neurobiological process than a single reward pathway.”

She added: “We see a range of experiences in clinical practice; some users report a decrease in libido, others report an improvement, and many of these changes are better explained by a range of other factors. Research shows that losing weight and improving metabolic health can boost confidence, self-image and sexual self-esteem, which for many patients improves rather than decreases desire.”

Dix noted that because GLP affects reward areas of the brain, it is thought to reduce compulsive behaviors. “This could indeed imply a risk of anhedonia, a loss of pleasure in things. However, this is not generally observed… It is likely that GLP normalizes or stabilizes the system rather than simply blunting it.”

She said: “The research is still in its early stages, and this is an area that truly merits more clinical investigation. Patients should feel comfortable raising concerns about emotional or sexual changes with their prescribing clinician.”