This week: the unregulated peptide market made the kind of news regulators have been warning about, and a scale mystery that looks worse than it usually is.

Let's go. ☕

The week the peptide gray market stopped being theoretical

That line came from a Sky News investigation into the unregulated peptide market. This week, it stopped sounding hypothetical.

A documented injury broke through

Australian regulators reported that a person was hospitalized after uncontrollable vomiting caused a torn esophagus following use of a product sold as retatrutide. Then the TGA tested the vial.

It contained no retatrutide. Instead, it contained undeclared semaglutide at roughly eight times the level found in semaglutide products assessed by the regulator.

That is the part worth sitting with. The product was not simply unapproved. It was not what it claimed to be.

Days earlier, Sky News had published an undercover investigation into peptides sold through social media, while the American Medical Association had already published physician guidance this year on the growing use of injectable peptides. Different outlets. Same problem.

The FDA is counting what it can see

The FDA has public adverse-event numbers for compounded semaglutide and tirzepatide. As of May 31, 2026, it had received 990 reports associated with compounded semaglutide and more than 730 associated with compounded tirzepatide. That is more than 1,700 reports combined.

Those reports do not prove the compounded medication caused every event, and the FDA says the numbers are likely underreported. But those numbers should not be confused with gray-market peptides like BPC-157, GHK-Cu, or TB-500. For products sold outside legitimate drug and compounding channels, there is no comparable national count. That is part of the problem.

Why this matters for women

One increasingly visible on-ramp into peptides is beauty. Copper peptides are already familiar from skincare. Then the same name shows up in a vial. NPR recently documented that exact shift with GHK-Cu, from creams into injections, even though the human evidence for injectable use remains extremely limited.

The word is the same. The evidence and quality controls are not.

What to know

• A seller's label or certificate of analysis cannot, by itself, prove that an injectable product contains what it claims, at the concentration claimed, or that it is sterile.
• Keep the categories separate: an FDA-approved medication, a legitimately compounded product made under applicable 503A or 503B rules, or a product sold outside those channels. They are not interchangeable.
• If someone experiences a suspected reaction or product-quality problem, consumers and patients can report it directly to FDA MedWatch.

The FDA already says compounded-drug adverse events are likely underreported. For gray-market products, the blind spot is even larger. Sometimes “we don't know” is not reassuring. Sometimes it is the warning.

“The scale hasn't moved in two weeks. The drug stopped working.”

What the evidence says. Two flat weeks do not prove that the medication stopped working. Body weight is noisy. Water, sodium, glycogen, food in the digestive tract, and menstrual-cycle fluid shifts can all change the number on the scale without representing the same change in body fat. One study found body weight was about 0.45 kg higher during menstruation, largely because of extracellular water. So yes, the scale can sit still while other things are changing.

But one internet explanation deserves retiring. You will often hear that the body holds water while fat disappears and then suddenly releases it all at once: the “whoosh effect.” Short-term water shifts are absolutely real. A predictable calorie-deficit whoosh mechanism is not well established. Real plateaus happen too, but researchers study them over much longer periods than two weeks. In a tirzepatide analysis, plateau was assessed across 12-week intervals, with most participants reaching one after months of treatment. So a two-week stall and a months-long plateau are not the same thing.

I think about side effects in levels. Nausea, constipation, diarrhea, abdominal discomfort, and fatigue are all commonly reported with GLP-1 medications, especially when treatment is starting or the dose is changing. A mild symptom that is improving is very different from something that keeps getting worse or starts affecting how well you can eat, drink, sleep, or function. That is when I would bring your prescriber into the conversation rather than assuming you just have to push through it.

Repeated vomiting or diarrhea that makes it difficult to stay hydrated, severe or persistent abdominal pain, fainting or significant weakness, or symptoms that are rapidly getting worse deserve prompt medical attention.

The important part is not memorizing a perfect list. It is knowing that the side-effect conversation is supposed to continue after the first prescription.

Mais, PharmD, Medical Reviewer, Pep in Her Step

• GLP-1s and PCOS: the full evidence review on weight, cycles, and hormones.
• The restart problem: why the medication can feel weaker after a coverage gap, and what's actually known.
• Planning a pregnancy on a GLP-1: the conversation prescribers keep skipping.