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GLP-1 Medications: 7 Things You Need to Know Before Starting
By Dr. Samantha Pfeiffer, ND — Head 2 Toe Spine & Sports Therapy
Medical Disclaimer: This article is for educational purposes only and reflects the professional observations of Dr. Samantha Pfeiffer, ND, based on current research and clinical experience. It is not a substitute for personalized medical advice. GLP-1 medications are prescription drugs. Always consult a licensed healthcare provider before starting, adjusting, or stopping any medication.
GLP-1 medications (Ozempic, Wegovy, Mounjaro, and more) are everywhere right now. Patients ask about them at every appointment. People discuss them at dinner parties. And with that level of attention comes a level of misinformation that genuinely concerns me.
I have been working with patients on GLP-1 therapy for several years. What I have seen in my practice, and what the research is beginning to confirm, tells a more nuanced story than the headlines suggest. There are real benefits. There are also real risks that don't get enough attention, and some genuinely dangerous territory in how people are accessing these medications.
Here are seven things I think every person considering or currently on a GLP-1 medication should know.
01 — The Drug Everyone Is Talking About Isn't Legal Yet. Here's What That Means
Retatrutide · FDA Status
Retatrutide (also identified in research as LY3437943) is the next-generation GLP-1 drug being developed by Eli Lilly. If you have been to any social gathering lately, someone has probably mentioned it. The buzz is real, and the early trial data gives some reason for it.
But the critical piece: as of this writing, retatrutide has not received FDA approval. That doesn't mean people aren't accessing it. It means those people are doing so outside of a regulated, clinically supervised framework, and that carries serious risk that I want people to understand before pursuing this route.
If you pursue any compounded GLP-1, ask this first: Request a Certificate of Authenticity (COA) from the compounding pharmacy. If they cannot produce one, do not take that medication. A COA verifies dosage accuracy, sterile compounding practices, and that the product contains what it claims to. No COA, no injection.
Two population studies from Eli Lilly (one in patients without diabetes, one in patients with Type 2 diabetes) examined outcomes over 80 weeks. The weight loss data is significant. Retatrutide is a triple agonist, acting on three receptor sites compared to the one or two targeted by semaglutide or tirzepatide. That mechanism is what the early data reflects. Long-term risks and benefits are still under evaluation, and trial averages do not predict individual outcomes.
02 — Black Market GLP-1s: One Question That Could Protect Your Health
Safety · Compounded Medications
The demand for GLP-1 medications has created a significant black market. Compounded versions of semaglutide, tirzepatide, and other GLP-1 drugs are sold through online pharmacies and unregulated channels. Some are legitimate. Many are not.
When you inject a substance without verified documentation, you genuinely do not know what you are putting into your body. The medication strength may be incorrect: dangerously high or completely ineffective. Sterile compounding standards may not have been followed. Preservative agents may be absent or inappropriate. There are documented cases of mold contamination in improperly compounded injectables.
The one question to ask any pharmacy: "Can you provide a Certificate of Authenticity (COA) for this medication?" A legitimate compounding pharmacy will provide this. It confirms drug identity, concentration, sterility testing, and preparation standards. This is not an unreasonable request. It is a basic patient safety measure.
I have seen patients in my practice who experienced adverse reactions tracing back to improperly compounded medications. The cost savings are not worth the risk. If you are pursuing GLP-1 therapy through a compounding pharmacy, verify their COA process before anything else.
"Almost a quarter of the mass people lose on GLP-1s is lean muscle, not just fat. If you are not actively protecting that muscle, you are trading one health problem for another." — Dr. Annie Armstrong, DC, Head 2 Toe Spine & Sports Therapy
03 — GLP-1 and Cancer: What the "50% Reduction" Headline Actually Means
Cancer Research · Media Literacy
You may have seen 2026 headlines suggesting GLP-1 medications reduce cancer spread by as much as 50%. This is being discussed widely, and I want to address it directly. The gap between the headline and the actual study is significant.
The 50% figure came from one study looking specifically at lung cancer. The researchers examined medical records retrospectively, meaning they looked back at existing patient data rather than randomly assigning cancer treatments in a controlled trial. That distinction matters enormously. Retrospective observational studies can suggest associations. They cannot establish that a medication caused a particular outcome.
What the evidence does and does not support: GLP-1 medications are not an established cancer treatment. Some research suggests possible associations between GLP-1 use and reduced metastatic spread in certain cancers, but these findings are preliminary. We do know that obesity increases all-cause mortality, and reducing obesity has meaningful health benefits. Always follow your oncology team's guidance. Approach GLP-1 cancer headlines with appropriate skepticism until more rigorous evidence emerges.
Misinformation in this space can be genuinely dangerous. Patients have asked whether they should use GLP-1 medications as a cancer prevention strategy based on these headlines. The honest answer is: the current evidence does not support that application, and decisions about cancer treatment should involve your oncologist, not a news article.
04 — You're Losing Muscle, Not Just Fat. Most People Don't Know It
Body Composition · Muscle Health
This is the conversation I have more than almost any other with GLP-1 patients. Someone is losing weight on the scale, feeling like they are making progress, and they are, in some respects. But what they are losing is not only fat.
Research and clinical observation consistently show that approximately one quarter of the mass lost during GLP-1 therapy is lean muscle tissue, not fat. Patients are also losing collagen and other soft tissue mass. And because GLP-1 medications significantly suppress appetite, many people are not consuming adequate protein, which means the body turns to muscle as a protein source.
Why this matters long-term: Muscle mass is the single most important longevity factor we can influence, particularly from age 40 onward. Loss of lean mass affects metabolic health, joint stability, cardiovascular resilience, and functional independence. A GLP-1 program that does not actively protect muscle is an incomplete program. Protein targets and strength training should be part of any clinically supervised GLP-1 plan.
At Head 2 Toe, we use an InBody scanner before and during GLP-1 therapy to give patients an accurate baseline and ongoing measurement of lean mass, fat mass, bone density, and hydration. If you are on a GLP-1 program without a body composition assessment, that is a meaningful gap in your monitoring.
05 — Retatrutide vs. Semaglutide: What the Side Effect Profiles Actually Show
Retatrutide vs. Semaglutide · Side Effects
One of the most common questions I receive is how retatrutide compares to semaglutide (Ozempic/Wegovy) in terms of side effects and benefits. Based on currently available trial data, here is an honest comparison, with the important caveat that retatrutide's long-term profile is still being established.
Both drugs share a common set of gastrointestinal side effects: nausea, diarrhea, and digestive discomfort are reported across the GLP-1 class. Retatrutide trial participants also reported skin discomfort at injection sites and occasional dizziness or lowered blood pressure. Both drug classes offer well-documented benefits: appetite suppression, improved blood sugar regulation, and anti-inflammatory effects.
One notable difference in current reporting: Retatrutide trials have not yet produced reports of the eye damage (non-arteritic anterior ischemic optic neuropathy) that has been associated with semaglutide in some patients. This is worth noting, though retatrutide is newer and has had significantly less long-term observation time. Absence of a reported risk in early trials is not the same as absence of risk.
The triple-agonist mechanism of retatrutide appears to produce stronger weight loss outcomes in early trials compared to single or dual-agonist drugs. Whether that translates to a better long-term risk-benefit profile is still being established. Trial averages are population statistics. They describe groups, not individuals.
06 — Hair Shedding on GLP-1? There's One Blood Test That Matters Most
Hair Loss · Iron Deficiency
Hair shedding is the most common complaint I hear from GLP-1 patients, typically appearing around the three-month mark. A patient who is losing weight and feeling good suddenly notices significant hair loss, and it is genuinely distressing. Here is what is likely happening and what to actually check.
Significant or rapid weight loss, combined with reduced food intake, can put the body in a state that deprioritizes hair growth. When nutrient availability is limited, the body allocates resources to essential systems first. Hair follicles are not in that priority tier. But nutritional deficiency is only part of the picture.
Check your ferritin: Ferritin is the protein that stores iron in your body. When ferritin levels drop, it signals that iron stores are becoming depleted. Iron is essential for oxygen transport, cellular energy, and hair follicle function. Iron deficiency is strikingly common in my practice, even in otherwise healthy patients. If you are experiencing hair shedding on a GLP-1 medication, ask your provider to check ferritin specifically, not just a general iron or hemoglobin panel. They are different measures.
Regular blood work is an important part of any GLP-1 program. If your ferritin is low, options may include dietary adjustments, oral supplementation, or in some cases IV iron therapy, which we offer at Head 2 Toe. Hair shedding during GLP-1 therapy is often addressable, but only if you identify the underlying cause.
07 — Coming Off the Medication: The Mental Health Piece Nobody's Talking About
Transitioning Off · Mental Health
Many patients eventually transition off GLP-1 medications, whether due to cost, personal choice, reaching their goals, or a change in health status. The physical side of that transition gets some attention: appetite may return, weight regain is a documented concern, and some patients notice increased joint discomfort. There are supplements and fiber products that may help support satiety during this period, and a thoughtful transition timeline matters.
But the mental health dimension of coming off GLP-1 medications is something I feel is significantly underaddressed in most clinical conversations. These medications quiet what many patients describe as "food chatter," that persistent mental noise around eating, cravings, and food-related decision-making. When the medication stops, that chatter may return.
What I tell patients before they transition off: Build your mental frameworks while the medication is still supporting you, not after the chatter comes back. What is your response when a craving hits? What does satisfaction that is not food-based look like for you? What habits have you built during this period that you can carry forward? These are not questions to answer in the moment of temptation. They need to be decided in advance and practiced while you still have the medication's support.
The cognitive and behavioral preparation for coming off GLP-1 therapy deserves as much clinical attention as the physical preparation. If this is not part of your conversations with your provider, it is worth raising directly. A GLP-1 program that does not prepare you for what comes after is an incomplete one.
Have Questions About GLP-1 Therapy?
Dr. Samantha Pfeiffer, ND offers free 15-minute consultations to discuss whether GLP-1 therapy is appropriate for your health goals, and what a medically supervised program looks like.
No commitment required · Lynnwood, WA · Also available via telehealth
