By the ShopMedRx editorial team · Published October 26, 2026
How ShopMedRx Works: From Online Assessment to Delivery
Here's how ShopMedRx works in one breath: you complete an online health assessment, a clinician licensed in your state reviews it, and they prescribe only if treatment is clinically appropriate for you. If they do, a state-licensed 503A compounding pharmacy prepares your medicine and ships it in unmarked packaging.
That's the answer to the question you probably typed into your phone at 11pm, somewhere between "is this legit?" and "what am I actually signing up for?" Below, we'll walk through each step, explain how semaglutide and tirzepatide work in plain English, and cover the safety details worth knowing before you decide anything.
The short version
- ShopMedRx starts with an online health assessment. A clinician licensed in your state decides whether to prescribe, and you aren't charged for medication if you're not prescribed.
- Semaglutide acts on one appetite-related hormone signal (GLP-1). Tirzepatide acts on two (GIP and GLP-1). They're related, not identical.
- The big trials studied FDA-approved products, not compounded ones, and they report group averages. Individual results may vary.
- Stomach side effects are common, and both medicines carry a boxed warning about thyroid tumors seen in animals. Compounded medications are not FDA-approved.
How does ShopMedRx work, and who decides your treatment?
A licensed clinician decides, not a sales page. ShopMedRx is the online front door: you answer questions about your health, and a clinician licensed in your state reads them.
If the clinician decides a prescription fits, they write it. If they don't, you aren't charged for medication. A prescription is not guaranteed, and that's how it should be.
ShopMedRx is available in all 50 states plus DC, although some services may not be available everywhere. This article focuses on weight management: semaglutide injections, tirzepatide injections or oral semaglutide. The same process also covers longevity treatments and ED treatments, and our how it works page lays out the steps.
Since weight management is the topic here, let's start with the part that confuses people most: what these medicines actually do.
How does semaglutide work in your body?
Semaglutide copies a hormone your gut already makes, called GLP-1. Think of GLP-1 as the "I'm full" text your gut sends your brain after a meal. Semaglutide is a man-made version, which the label calls a GLP-1 receptor agonist.[1]
"Receptor agonist" just means it fits the same lock the natural hormone does. The label says that lock, the GLP-1 receptor, helps regulate appetite and calorie intake.[1]
There's a second effect you'll feel in your day. The label says semaglutide delays gastric emptying, which is a medical way of saying food leaves your stomach more slowly. That can also affect how other pills you swallow are absorbed.[1]
The FDA-approved injection is given once a week. The FDA-approved tablet is a daily version, and its label asks for an empty stomach, plain water and a 30-minute wait before food, drinks or other pills.[1] Our oral semaglutide guide and semaglutide injections guide cover the day-to-day details, and what GLP-1 is goes deeper on the hormone.
Tirzepatide shares some of this story, then adds a twist.
How does tirzepatide work, and how is it different?
Tirzepatide works on two hormone signals instead of one: GLP-1 and a second one called GIP.[2]
Picture two volume knobs for appetite instead of one. That's an analogy only. What the label actually says is that tirzepatide binds and activates both receptors, and that it decreases calorie intake, likely by affecting appetite.[2] Like semaglutide, it also slows gastric emptying.[2]
The schedule looks familiar: once a week, starting low and stepping up. The label raises the dose in steps, no sooner than every four weeks.[2] Our tirzepatide injections guide has the full picture.
One rule applies to both medicines. The tirzepatide label says not to combine it with any GLP-1 receptor agonist, and the semaglutide label says the same about other semaglutide products and GLP-1 medicines.[2][1]
So does the extra signal mean more weight loss? Here's what the big trials found, and what they can't tell you.
What did the big trials find for semaglutide and tirzepatide?
On average, people in these trials lost somewhere between about a seventh and a fifth of their starting weight, alongside lifestyle support. Individual results may vary, and neither trial studied compounded medications.
The semaglutide trial, called STEP 1, followed adults with overweight or obesity who didn't have diabetes. They took weekly semaglutide injections or a placebo for 68 weeks, and everyone got lifestyle support.[3] On average, the semaglutide group lost 14.9% of body weight, compared with 2.4% on placebo.[3]
Reviewers have noted a fair caveat: people who join a trial may be more committed to weight loss than the general population.[3] Weight regain after stopping treatment has also been documented in a follow-up study.[3]
The tirzepatide trial, SURMOUNT-1, tested three weekly doses against a placebo for 72 weeks in adults without diabetes, again with lifestyle support.[4] Average weight change ran from 15.0% on the lowest dose to 20.9% on the highest, compared with 3.1% on placebo.[4]
Please don't read those numbers as a race. They came from different trials with different designs, and both were funded by the manufacturers.[3][4]
| At a glance | Semaglutide | Tirzepatide |
|---|---|---|
| Acts on | GLP-1 receptor[1] | GIP and GLP-1 receptors[2] |
| Main trial | STEP 1, 68 weeks[3] | SURMOUNT-1, 72 weeks[4] |
| Average weight change | 14.9% (placebo 2.4%)[3] | 15.0% to 20.9%, by dose (placebo 3.1%)[4] |
| Product studied | FDA-approved manufacturer's product, not compounded | FDA-approved manufacturer's product, not compounded |
Now the part that matters as much as the weight numbers: what these medicines can do to you.
What are the side effects and safety warnings you should know about?
The most common side effects are stomach-related, and both medicines carry a boxed warning, the FDA's most serious label warning. The figures below come from the labels and trials of the FDA-approved products. Compounded versions weren't studied in them, so a clinician can tell you what applies to you.
Boxed warning and who should not use these medicines
Both warnings are about thyroid C-cell tumors. In rodents, semaglutide causes them at clinically relevant exposures, and it's unknown whether it does in humans, including a rare cancer called medullary thyroid carcinoma (MTC).[1] For tirzepatide, the label says the same about rats and says the human relevance is unknown.[2] Symptoms to report include a neck lump, trouble swallowing, trouble breathing or hoarseness that won't go away.[1]
Neither medicine is for people with a personal or family history of MTC, or with MEN 2, a rare inherited endocrine condition.[1][2] Both labels also rule out anyone with a prior serious allergic reaction to the medicine or its ingredients.[1][2]
Common side effects
In the semaglutide label's weight-loss trials, 73% of adults reported stomach or digestive reactions, versus 47% on placebo.[1] For tirzepatide, the pooled figure was 56% at each dose versus 30% on placebo.[2]
| Side effect | Semaglutide vs placebo | Tirzepatide vs placebo |
|---|---|---|
| Nausea | 44% vs 16%[1] | 25% to 29% vs 8%[2] |
| Diarrhea | 30% vs 16%[1] | 19% to 23% vs 8%[2] |
| Vomiting | 24% vs 6%[1] | 8% to 13% vs 2%[2] |
| Constipation | 24% vs 11%[1] | 11% to 17% vs 5%[2] |
These are separate trials (semaglutide 2.4 mg for up to 68 weeks, tirzepatide 5, 10 and 15 mg for up to 72 weeks), so they're not a head-to-head comparison.
The encouraging part is timing. In STEP 1, nausea and diarrhea were the most common effects, and they were typically mild to moderate and faded with time.[3] The tirzepatide label says most nausea, vomiting and diarrhea happened during dose escalation and eased over time.[2] In STEP 1, 4.5% of the semaglutide group stopped treatment because of stomach problems, versus 0.8% on placebo.[3]
Other warnings to know about
- Pancreatitis: both labels say to stop the medicine if it's suspected and to report severe belly pain that doesn't go away, with or without vomiting.[1][2]
- Gallbladder disease: gallstones and gallbladder inflammation occur. With the semaglutide injection, adult gallstones were 1.6% versus 0.7% on placebo. Report upper belly pain, fever, yellow skin or eyes, or clay-colored stools.[1][2]
- Severe stomach reactions: they were reported in 4.1% of semaglutide-treated adults versus 0.9% on placebo, and in 1.7% to 3.1% on tirzepatide versus 1%. Neither is recommended in severe gastroparesis (a very slow-emptying stomach).[1][2]
- Dehydration and kidney injury: ongoing vomiting or diarrhea can cause it. Drink fluids and report symptoms that don't settle.[1][2]
- Low blood sugar: the risk is higher with insulin or sulfonylureas, and the labels point to lowering those doses.[1][2]
- Serious allergic reactions: anaphylaxis and angioedema have been reported. Stop and get care.[1][2]
- Eye changes with type 2 diabetes: report any vision changes.[1][2]
- Heart rate: resting heart rate rose by a few beats per minute on average. Report palpitations.[1][2]
- Surgery or sedation: tell your care team beforehand, because food or liquid can enter the lungs under anesthesia or deep sedation.[1][2]
- Pregnancy: both medicines may harm a fetus and should be stopped once pregnancy is recognized. The semaglutide label says to stop at least 2 months before a planned pregnancy, and it advises against breastfeeding with the tablets.[1][2]
- Other medicines: slower stomach emptying can change how oral medicines are absorbed. The tirzepatide label says to switch to a non-oral birth control method, or add a barrier method, for 4 weeks after starting and after each dose increase. Oral semaglutide raised levothyroxine levels by 33% in label testing.[1][2]
When to get help
Call 911 for swelling of the face, lips, tongue or throat, trouble breathing or swallowing, or fainting. Contact a clinician the same day, or go to urgent care, for severe belly pain that won't ease, vomiting or diarrhea that stops you keeping fluids down, a racing heart at rest, sudden vision changes, signs of low blood sugar or a new neck lump. If you think you've taken too much, call Poison Help at 1-800-222-1222 or go to the ER.[1][2] Tell your clinician about every medicine you take before you start.
Next, the word that sits in front of the medicines ShopMedRx offers: compounded.
What does "compounded" mean for the medicine you'd receive?
A compounded medicine is prepared by a pharmacy for an individual patient, and it is not FDA-approved. The FDA says this means it doesn't verify the safety, effectiveness or quality of compounded drugs before they're marketed.[6]
It also isn't a generic. A generic is approved by the FDA and has to show therapeutic equivalence to a brand-name drug, while a compounded drug has no such approval.[6] The FDA adds that compounded drugs should be used only when a patient's needs can't be met by an approved drug.[6] That's one reason a clinician's judgment matters here.
The FDA also has practical advice for compounded injectables. Throw away a multi-dose vial 28 days after first use, use a new sterile needle and syringe for every dose, and don't use anything that arrives warm. It has also received reports of dosing errors with compounded injectable semaglutide, so ask your clinician or pharmacy how to measure your dose.[5]
The FDA lists telehealth red flags too. They include claiming a compounded drug is the same as an approved one, prices that seem too good to be true, damaged packaging or missing instructions, and no screening or prescription from a licensed doctor.[5] At ShopMedRx, a clinician licensed in your state reviews your assessment before anything is prescribed. If you want to check any company yourself, our guide to verifying ShopMedRx shows what to look for.
The trial results above came from FDA-approved products. Compounded versions weren't studied in them.
What does ShopMedRx include, and what does it cost?
There's no membership fee, pricing is shown up front, and GLP-1 plans include free 1-on-1 care coaching. Current pricing is on the product pages, starting at our weight management page, so you can see it before you commit to anything.
A few practical points:
- ShopMedRx does not bill insurance, and products are HSA/FSA reimbursable.
- Your medicine ships in unmarked packaging.
- You can cancel any time.
Ready to see how the steps fit together? Here's the whole path.
Getting GLP-1 treatment through ShopMedRx
- Take the online health assessment. You answer questions about your health history and medicines.
- A licensed clinician reviews it. A clinician licensed in your state prescribes only if it's clinically appropriate. If you aren't prescribed, you aren't charged for medication.
- A 503A pharmacy prepares and ships. A state-licensed 503A compounding pharmacy prepares your medicine and ships it in unmarked packaging.
Compounded medications are not FDA-approved, and the FDA does not review compounded drugs for safety, effectiveness or quality.[6]
If you're curious whether this route fits your situation, you can check if you qualify online. Only a clinician can make that call.
Bottom line
ShopMedRx is an online assessment, a review by a clinician licensed in your state, and a 503A pharmacy that ships what's prescribed. Semaglutide and tirzepatide work on appetite-related hormone signals, and the trials show group averages with real stomach side effects and a boxed warning. If that sounds worth a conversation with a clinician, the assessment is the next step.
Frequently asked questions
Will ShopMedRx always prescribe me a medication?
No. A clinician licensed in your state reviews your online health assessment and prescribes only if it's clinically appropriate. A prescription is not guaranteed. If you aren't prescribed, you aren't charged for medication.
How does semaglutide work for weight loss?
Semaglutide is a GLP-1 receptor agonist, a man-made version of a gut hormone that helps regulate appetite and calorie intake.[1] The label also says it delays gastric emptying, meaning food leaves your stomach more slowly.[1]
How is tirzepatide different from semaglutide?
Tirzepatide activates two receptors, GIP and GLP-1, while semaglutide activates GLP-1 only.[2][1] The trials were separate and designed differently, so their weight results shouldn't be compared directly.[3][4] A clinician decides which medicine, if any, fits your health history.
Are compounded semaglutide and tirzepatide FDA-approved?
No. The FDA says compounded drugs are not FDA-approved, so it doesn't verify their safety, effectiveness or quality before they're marketed.[6] They're also not generics of brand-name drugs.[6] The trials discussed here studied FDA-approved products, not compounded ones.
Can I use HSA or FSA funds, or insurance?
ShopMedRx products are HSA/FSA reimbursable. ShopMedRx does not bill insurance, so you pay directly. Check with your plan administrator about how to submit a claim. Pricing is shown up front on the product pages, and there is no membership fee.
Can I take semaglutide and tirzepatide together?
No. The tirzepatide label says combining it with any GLP-1 receptor agonist is not recommended.[2] The semaglutide label says the same about other semaglutide products or GLP-1 medicines.[1] Tell your clinician about every medicine you take.
Talk to a licensed clinician
Before you start, stop or change any treatment, talk to a licensed clinician about your health history and other medicines. If you would like to see whether treatment from ShopMedRx could be appropriate for you, you can check if you qualify.
Important information
- This article is for general education and is not medical advice. Talk to a licensed clinician before starting, stopping or changing any treatment.
- All medications available through ShopMedRx are prescription only and are prescribed only if appropriate after a licensed clinician's review.
- Most medications we offer are compounded. Compounded medications are not FDA-approved, and the FDA does not review compounded drugs for safety, effectiveness or quality before they are marketed. They are not the same as, or generic versions of, brand-name drugs.
- Individual results may vary. Nothing in this article promises a specific result.
- Prescriptions are written by clinicians licensed in the patient's state, only when clinically appropriate. All prescriptions are filled by state-licensed 503A compounding pharmacies.
Sources
- DailyMed (NIH/NLM). WEGOVY (semaglutide) injection and tablets: prescribing information (SPL version 19, June 2026). 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee06186f-2aa3-4990-a760-757579d8f77b
- DailyMed (NIH/NLM). ZEPBOUND (tirzepatide) injection: prescribing information (SPL version 40, September 2026). 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b
- New England Journal of Medicine. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). 2021-03-18. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183
- New England Journal of Medicine. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). 2022-07-21. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
- U.S. FDA. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. 2026. https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss
- U.S. FDA. Compounding and the FDA: Questions and Answers. 2025. https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers