The GLP-1 Side Effect Nobody's Talking About: Lying

A study out of Florida State University, led by researcher Kyle Lazenby, found that GLP-1 users routinely conceal their use from the people closest to them. They also downplay how much weight they've actually lost. Or, they feel compelled to invent a medical justification just to preempt the judgment.

Check.

Check.

Check.

The frailty issues and other side effects made it even harder to play along. 

Three falls, over a few years.

This woman who had never once fallen in the decades I'd known her, suddenly going down like a tree, again and again, her body no longer able to catch her the way it used to.

One of these ended with an ambulance. Others involved waiting until strength came back and then crawling to a bed.

Here's what nobody tells you at the pharmacy counter, and what I only learned by going down a research rabbit hole: a real and meaningful chunk of the weight people lose on drugs like Ozempic and Wegovy is not fat. It's muscle. 

Depending on which trial you're reading, somewhere between a quarter and nearly 40 percent of total weight lost on semaglutide comes off as lean mass — the STEP 1 trial's body-composition substudy put that number close to 40 percent, and Regeneron's COURAGE trial found people on semaglutide alone lost roughly a third of their total weight as lean tissue.

This is not a fringe concern.

An editorial in Annals of Internal Medicine raised the alarm specifically about older adults, who are already losing 12 to 16 percent of their skeletal muscle simply from the passage of time, and who now face a drug that can strip away a quarter to nearly half of what little reserve they have left. Up to half of adults over eighty already qualify as sarcopenic — muscle loss severe enough to threaten walking, balance, and independence. Dr. John Batsis, an obesity medicine physician at UNC who studies physical function in aging bodies, put it about as plainly as a doctor can: losing muscle mass and strength leads to functional decline, disability, nursing home placement, and death.

And then there was the vomiting. Yes this person had had surgery and yes, the vomiting went on for weeks and weeks. Way beyond what doctors told her it would.

Another dead giveaway.

What I found is that gastroparesis — literally, stomach paralysis — has become one of the most sobering discoveries to come out of GLP-1 research in the last two years. A 2024 study out of the University of British Columbia, published in JAMA and built on insurance records from roughly sixteen million patients, found GLP-1 users were 66 percent more likely to be diagnosed with gastroparesis than people not on the drugs, on top of higher rates of pancreatitis and bowel obstruction. Researchers presenting related findings at Digestive Disease Week described patients vomiting fifteen to twenty times a day — a frequency that led to actual lawsuits against Novo Nordisk. One of the lead researchers, Dr. Prateek Sharma, told reporters the real-world odds of GI side effects severe enough to force someone off the drug entirely run around one in three.

A Boston Globe investigation into GLP-1 culture described jealousy, secrecy, and lies "rippling through friendships, marriages, and even doctors' appointments" as these drugs have gone mainstream.

Guardian readers, writing in about their own GLP-1 journeys, described hiding the drugs from their own children — one parent wrote that their twenty-year-old daughter felt "worried, angry.”

Newsweek ran its own informal investigation into who discloses and who hides, and found the same split I lived through firsthand: some people announce it happily, and some people build an entire alternate narrative rather than say the word out loud.

Swedish researchers tracking roughly 12,500 patients through rapid weight loss found divorce rates nearly double the general population within six years — not necessarily because the drug ruins marriages, researchers are careful to note, but because rapid transformation surfaces whatever was already cracked underneath it, including, I'd wager, whatever was already cracked about how two people tell each other the truth.

So here is what I actually want to talk about, which is not muscle loss or stomach paralysis.

It's what it does to a person, to be lied to, slowly, for over a year, by someone you'd have taken a bullet for.

Psychologist Bella DePaulo has spent her career studying who we lie to and why, and found that we don't save our biggest lies for strangers.

We tell our biggest, highest-stakes lies to the people closest to us, precisely because those are the relationships with the most to lose.

Betrayal trauma researcher Jennifer Freyd, at the University of Oregon, has a term for what happens next in the person being lied to — "betrayal blindness," a kind of protective fog the mind generates so you don't have to fully register that someone this close is deceiving you this completely, because registering it is almost unbearable.

I didn't have the fog.

I had the opposite of the fog. 

I was not willing to jump into the lie with my close person. I loved her that much. And I loved myself that much.

Psychologist Susan Krauss Whitbourne has written that what actually wounds us about being lied to isn't usually the size of the lie — it's what the lie tells us about how the liar sized us up.

This person isn’t worth telling the truth too or this person can’t handle the truth or this person can’t be trusted with my secret

I don't have a tidy ending for you, because I don't have one for myself yet. She's still on the medication. Still managing the side effects (including the darkest one: dishonesty). Still, I assume, deciding day by day what version of the truth she can afford to hand out.

I've stopped pretending I believe the Prozac thing, and I've stopped needing her to perform a big confession scene for me, because I think I understand now that the confession isn't really the point.

The point is that somewhere in the last two years, losing weight became more important than her relationship with me.

And no amount of muscle mass, regained or lost, is going to give her the backbone to tell the truth.

Sidebar: What to do When Someone is Lying to Your Face

There is a peculiar kind of psychological injury that comes from knowing someone you love is lying to you while they continue to insist that they are not.

The problem is no longer simply the original secret. The relationship itself starts becoming unstable because every conversation now requires the person being lied to to choose between two realities: what they can plainly see and what someone they trust keeps telling them is true.

Research on deception suggests that lying also carries psychological costs for the person doing it.

Producing a lie generally requires more cognitive control than telling the truth. The liar has to remember what actually happened, suppress that information, construct an alternative account and keep the new story consistent over time. Reviews of deception research have repeatedly found that these processes place demands on working memory, inhibition and executive control. 

Dishonesty can also change the liar’s relationship with the person being deceived. Across eight studies involving more than 2,500 participants, researchers found that behaving dishonestly reduced people’s ability to accurately read other people’s emotions. The researchers traced part of that effect to a weakening of what psychologists call “relational self-construal” — the degree to which people experience themselves as connected to others. 

Even when a lie succeeds, it may not feel psychologically cost-free. Experimental research has found that undetected deception can produce guilt, reduce satisfaction with an interaction and make the deceiver less interested in interacting with the same person again. 

So what do you do when you know someone you love is lying?

• Say what you know without turning the conversation into a courtroom. “I don’t believe that explanation” can be more useful than spending hours trying to force a confession.

• Refuse to participate in the false version of events. You do not have to pretend to believe something simply to preserve peace.

• Focus on the relationship rather than proving every detail. The central question becomes: Can we have a relationship in which I am expected to accept things I believe are untrue?

• Set a boundary around your own participation. A boundary might mean declining to discuss the subject, limiting contact or saying that greater closeness requires honesty.

• Leave the responsibility for telling the truth with the person who owns it. You cannot extract honesty from another adult.

• Pay attention to what prolonged deception does to you. Chronic suspicion can turn relationships into investigations, which is damaging even when the suspicion is justified.

Close relationships are particularly vulnerable to deception precisely because they involve repeated interaction, intimate knowledge and the expectation that each person will protect the other’s vulnerabilities. That is why a seemingly private lie can become much larger than the subject being concealed. 

Sometimes the most consequential part of a lie is not what was hidden.

It is what keeping the lie required the relationship to become.

GLP-1 Drugs After 70: What Deserves Extra Attention

This is the crazy thing. I don't care if someone is on a GLP-1. Lots of my friends are on them. Each to his own. What makes me feel icky is having the person closest to me in the world lie to my face and them expecting me to go along with it. With no change in our relatioship.

But despite that I wanted to take a look at the risks.

Semaglutide is not automatically safe or not safe because someone is over 70 or obese.

FDA prescribing information says clinical trials did not identify an overall difference in Ozempic's safety or effectiveness between older and younger adults, although it specifically notes that greater sensitivity in some older people cannot be ruled out. Importantly, relatively few Ozempic trial participants were 75 or older. 

Age nevertheless changes the equation because older adults generally have less physiological reserve. A side effect that is merely unpleasant at 45 — several days of vomiting, sharply reduced food intake or rapid weight loss, for example — may have much greater consequences at 75.

Potential concerns include:

• Muscle and lean-tissue loss. Weight lost on GLP-1 drugs is not exclusively body fat. Reviews have found that a meaningful portion can come from lean mass. This matters especially in older adults, who may already be experiencing age-related sarcopenia. 

• Loss of strength or physical function. A 2025 observational study of older adults with type 2 diabetes associated semaglutide treatment with reductions in muscle mass, grip strength and walking speed, with greater concern in people who already had sarcopenia. Observational research cannot establish that semaglutide alone caused those changes, but the findings are clinically important. 

• Frailty and falls. Muscle loss, weakness, inadequate nutrition and dehydration can all contribute to frailty. Older adults with limited muscle reserves may therefore require closer monitoring during substantial weight loss.

• Nausea, vomiting, diarrhea, abdominal pain and constipation. These are among Ozempic's most commonly reported adverse reactions.

• Severe gastrointestinal problems. FDA labeling warns that severe GI reactions can occur and says Ozempic is not recommended for patients with severe gastroparesis.

• Dehydration and acute kidney injury. Persistent vomiting or diarrhea can cause volume depletion, and FDA labeling specifically warns about acute kidney injury associated with dehydration. That can be particularly consequential in an older patient.

• Gallstones and gallbladder inflammation. Acute gallbladder disease, including cholelithiasis and cholecystitis, is included in the FDA warnings. 

• Pancreatitis. Acute pancreatitis has been reported with semaglutide and other GLP-1 receptor agonists. 

• Hypoglycemia when combined with certain diabetes medications. The risk increases when Ozempic is used with insulin or insulin-secretagogue medications such as sulfonylureas. 

• Diabetic-retinopathy complications. People with pre-existing diabetic retinopathy may require monitoring, particularly when glucose levels improve rapidly. 

• Delayed stomach emptying. Semaglutide delays gastric emptying, which can affect gastrointestinal symptoms and may alter absorption of some oral medications. 

• Aspiration during anesthesia or deep sedation. Because the stomach may empty more slowly, FDA labeling warns about rare reports of pulmonary aspiration during procedures requiring general anesthesia or deep sedation. 

• Serious allergic reactions. Anaphylaxis and angioedema have been reported. 

• Thyroid C-cell tumor warning. Semaglutide caused thyroid C-cell tumors in rodents. Whether it causes these tumors in humans remains unknown. Ozempic is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN2. 

• Weight regain after stopping. This may be one of the most important risks to discuss before beginning treatment. In the STEP 1 extension, people who discontinued semaglutide regained approximately two-thirds of the weight they had lost during the following year.

• Possibly regaining fat faster than muscle. This is an emerging concern rather than a settled finding. Researchers studying older adults have warned that weight cycling after GLP-1 discontinuation could leave some patients regaining proportionally more fat than lean tissue, potentially worsening sarcopenic obesity. More research is needed. 

For an adult in their 70s or 80s, the relevant question therefore isn't simply, “How many pounds did this drug take off?”

It is also: What happened to muscle, strength, nutrition, hydration, balance and physical independence while those pounds were coming off — and what happens if the medication is eventually stopped?

(Sources: NIH; FDA Access Data)