GLP-1 pens postpartum: what the science says about safety and timing

What did @kylieajohnston actually say?

Not much, honestly. This is a fairly thin video. @kylieajohnston shows the remaining medication in a GLP-1 injection pen after four weeks of use, then documents week five. Her main substantive advice is "always talk to your pharmacist" repeated three times, plus a disclaimer: "I'm not a doctor. I'm just showing you my fifth week." She does not name the medication, dose, or brand. She notes that "pen one...twists a different way" and that "it's not for sure what you're getting," which is a surprisingly honest nod to compounded GLP-1 variability. The video is more of a vlog check-in than an instructional guide, which limits how much there is to fact-check. But the postpartum context and the casual pen-handling demonstration do raise real questions worth addressing.

Does the science back this up?

Her core implicit claim, that GLP-1 receptor agonists are being used for postpartum weight management, is factually happening, but the evidence base for this specific population is thin. The major semaglutide trials (STEP 1-4, Wilding et al., 2021, NEJM; Davies et al., 2021, Lancet) excluded pregnant and breastfeeding individuals entirely. Tirzepatide's SURMOUNT trials did the same. That means the safety and efficacy data everyone cites for GLP-1s does not apply to postpartum people who are breastfeeding. A 2023 review in Obstetrics and Gynecology by Tarleton et al. noted that semaglutide is detectable in breast milk in animal models, with no adequate human lactation data available. The FDA label for Wegovy explicitly states it should not be used during breastfeeding. Whether @kylieajohnston is breastfeeding is unknown, but the audience this video reaches, tagged postpartumbody and postpartumjourney, almost certainly includes people who are.

What did they get wrong (or right)?

She gets credit for the pharmacist advice. Repeatedly saying "always talk to your pharmacist" is genuinely useful, especially because compounded GLP-1 pens vary significantly in concentration, volume, and excipients depending on the compounding pharmacy. Her comment that "it's not for sure what you're getting" reflects a real regulatory issue. FDA warning letters issued in 2023 and 2024 flagged numerous compounding pharmacies for semaglutide potency and sterility concerns (FDA, 2024, MedWatch). That is not a minor caveat. That is a patient safety issue. Where the video falls short: showing pen fill levels without naming the drug or dose creates an implicit tutorial effect. Viewers in the comments will, and do, use this to estimate their own dosing. She never addresses the postpartum-specific risks, the breastfeeding contraindication, or whether she cleared this with an OB or prescriber rather than just a pharmacist. Pharmacists dispense. They do not manage postpartum medical care.

What should you actually know?

If you are postpartum and considering a GLP-1, a few things are not negotiable. First, if you are breastfeeding, the current guidance is to avoid semaglutide and tirzepatide. The data simply does not exist to call it safe, and animal data suggests transfer into milk (Novo Nordisk prescribing information, 2023). Second, compounded GLP-1 pens are not equivalent to brand-name Wegovy, Ozempic, Zepbound, or Mounjaro. They are not FDA-approved. Concentration errors in compounded products have resulted in hospitalizations, according to FDA adverse event reports. Third, postpartum bodies are in active hormonal recovery. Rapid weight loss via GLP-1 in the months after birth can affect milk supply, micronutrient status, and mood, none of which has been studied adequately in this group. Talk to your OB. Talk to a registered dietitian familiar with postpartum care. A pharmacist is a good start, as @kylieajohnston suggests, but it is not the whole picture.