Evidence
Evidence-based research
Every claim on GLP-1 Desk is tied to primary research or official labeling. Every claim the Desk publishes on GLP-1 drugs, tied to primary research or official labeling — each row below shows how many primary sources the piece cites, so you can see what is behind a conclusion before you open it.
35 explainers · 113 primary sources cited
Looking for a specific company rather than the science? All 508 providers the Desk has scored are in the provider dispatch index, and the ranked shortlists are on the rankings page.
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35 articles
The molecules
What the trial evidence actually shows about each drug, and how the delivery route and the brand name change the picture.
- Semaglutide vs Tirzepatide: Which Molecule Fits You5 sourcesThe two GLP-1 molecules head to head — trial weight-loss data, the single-vs-dual mechanism, and how to decide which one to ask your provider for.
- Injections vs Oral or Sublingual GLP-1: What to Know4 sourcesWeekly injections carry the trial-grade weight-loss evidence; oral and sublingual GLP-1 trade some data for convenience. How to weigh the route.
- Ozempic vs Wegovy: Same Drug, Two Different FDA Approvals4 sourcesOzempic and Wegovy are both semaglutide. What differs is the FDA-approved indication, the maximum dose, and a cardiovascular-risk claim only one carries.
- Wegovy vs Zepbound: What the Trials — and One Head-to-Head Study — Show5 sourcesWegovy is semaglutide, Zepbound is tirzepatide. The pivotal trials, a real head-to-head study, and what each drug's own FDA label adds the other doesn't.
- Mounjaro vs Zepbound: Same Drug, Two FDA Approvals4 sourcesMounjaro and Zepbound are both tirzepatide, from Eli Lilly. What differs is the FDA-approved use — and, since Dec. 2024, one has an approval the other doesn't.
- Rybelsus vs Ozempic: Oral vs Injectable Semaglutide3 sourcesRybelsus and Ozempic are both semaglutide, from Novo Nordisk, both approved only for type 2 diabetes — not weight loss. Here's what the route actually changes.
- Wegovy vs Saxenda: The Randomized Trial That Compared Them Directly4 sourcesSaxenda (liraglutide) came first; Wegovy (semaglutide) came later. A real randomized trial — STEP 8 — compared them directly. Here's what it found.
Compounded vs brand-name
The legal framework, the safety record, and where our own record cannot confirm what is in the vial.
- Compounded vs Brand-Name GLP-1: How to Read the Trade-Off6 sourcesBrand-name Wegovy and Zepbound are FDA-approved; compounded GLP-1 is not. Here is what that difference actually means for cost, access and safety.
- Is Compounded GLP-1 Legit and Safe?2 sourcesCompounded GLP-1 is legal but not FDA-approved. What 503A and 503B mean, why LegitScript verification matters, and how to vet a compounder before you buy.
Choosing a provider
How to read a provider's claims — the checks that separate a licensed operator from a storefront.
- How to Choose a GLP-1 Provider That Fits You2 sourcesA six-point checklist for picking a GLP-1 telehealth provider — price, state access, molecule, speed, support and licensing — matched to your situation.
- How to Tell If a GLP-1 Telehealth Provider Is Legitimate12 sourcesRed flags and a step-by-step verification checklist — state license lookups, pharmacy accreditation, instant-approval traps and pricing scams — for GLP-1 sites.
- Best GLP-1 Provider by Need: Budget, Oral, Fast Start, Nationwide2 sourcesNo provider wins on every axis. The Desk's best-for-X picks — cheapest, oral-capable, fastest onboarding and widest state reach — with the trade-offs.
Side effects & safety
What the FDA labels and pivotal trials actually report — real percentages, the boxed warnings, and what's reported but not on either label.
- GLP-1 Side Effects: What the Trials and FDA Labels Actually Show4 sourcesReal numbers from the pivotal trials and FDA labels — how common nausea and diarrhea are, the boxed warnings, and when a side effect means call your provider.
- GLP-1 and Muscle Loss: What the Body-Composition Data Shows4 sourcesGLP-1 weight loss isn't all fat. What DXA-scan substudies measured, why the lean-mass share varies so much between studies, and what it does and doesn't mean.
- GLP-1 and Hair Loss: What Causes It, and When It Stops2 sourcesHair thinning is not on the Wegovy or Zepbound label, but it is widely reported and increasingly studied — the mechanism, timing and who is affected.
- GLP-1 and Alcohol: What Happens When You Drink on Semaglutide or Tirzepatide2 sourcesNeither FDA label bans alcohol. A separate randomized trial found semaglutide reduced drinking in people with alcohol use disorder — two findings, not one.
- "Ozempic Face": What Causes It, and What the Evidence Actually Says2 sourcesFacial hollowing after rapid GLP-1 weight loss is real and now studied — the peer-reviewed evidence on why it happens, and what it doesn't prove yet.
- GLP-1 Drugs and Depression: What the FDA Warning and the Studies Show3 sourcesZepbound's label directs monitoring for mood changes. Here's why that warning exists, and what the largest cohort study to test it actually found.
- GLP-1 Drugs Before Surgery: What the Aspiration-Risk Evidence Shows2 sourcesGLP-1 drugs delay gastric emptying, raising aspiration risk under anesthesia. The actual gastric-ultrasound study data, and what it means for a procedure.
Dosing & technique
The FDA-approved titration schedules, injection technique, and what happens when a practice skips both.
- GLP-1 Dosage and Titration Schedules: Semaglutide and Tirzepatide2 sourcesThe FDA-approved dose-escalation steps for Wegovy and Zepbound, why the climb is slow by design, and what happens if you miss a week.
- How to Inject GLP-1 Medications: Sites, Rotation and Timing2 sourcesWhere the FDA-approved instructions say to inject Wegovy or Zepbound, how to rotate sites correctly, and the timing rules for a weekly dose.
- GLP-1 Microdosing: What It Is, and What the Evidence Says3 sourcesMicrodosing GLP-1 means going below the FDA-approved starting dose, usually via compounded product. No randomized trial has tested it — what that gap means.
Beyond weight loss
The outcomes trials behind GLP-1's newer FDA indications, and what happens when treatment stops.
- GLP-1, the Heart and the Kidneys: The SELECT and FLOW Trials4 sourcesSemaglutide's two newest FDA indications aren't about weight loss at all — they're for reducing heart-attack, stroke and kidney-disease risk directly.
- GLP-1 Weight Regain After Stopping: What the Withdrawal Trial Shows1 sourceWhat actually happened to STEP 1 participants a year after they stopped semaglutide — the real numbers, not the anecdote version.
- Zepbound and Sleep Apnea: What the SURMOUNT-OSA Trial Showed2 sourcesIn December 2024, Zepbound became the first drug ever FDA-approved for obstructive sleep apnea. The SURMOUNT-OSA trial numbers behind that approval.
- GLP-1 Drugs for PCOS: What the Trials Actually Show2 sourcesNo GLP-1 drug is FDA-approved for PCOS. What the randomized trials that exist found on weight, hormones, and reproductive outcomes — and their real limits.
Provider dispatches
Single-provider write-ups: the rung we filed, the rung the site would rather we filed, and the places a provider's own pages disagree with each other.
- The Edit Review: $209 Semaglutide, $309 Tirzepatide3 sourcesThe Edit publishes a semaglutide and tirzepatide ladder whose prepay maths checks out exactly, plus a full Spanish site. What we verified in August 2026.
- Pepti Review: $99 Semaglutide, and an Open Question3 sourcesPepti advertises $99 semaglutide flat at every dose. Its own production data carries a $299-$449 per-dose ladder. We could not break the tie — here is why.
- Trellis Vitality Review: $150 Semaglutide, and a Gap3 sourcesTrellis publishes a real 1/3/6-month GLP-1 table at $150 semaglutide and $199 tirzepatide. Everything else on the site is a starting-at number with no ladder.
- Auren Rx Review: $199 Semaglutide, $299 Tirzepatide2 sourcesAuren Rx publishes a subscribe rung and an explicit no-commitment rung on every SKU, plus a named microdose program. It never publishes the states it serves.
- Vyvron Review: Billed Every 4 Weeks, Not Monthly2 sourcesVyvron advertises $199/mo semaglutide but bills every four weeks — thirteen charges a year. Its tirzepatide has no monthly rung; the entry is $790 prepaid.
- Rehydra+ Review: A 6-Month Non-Cancelable Contract3 sourcesRehydra+ advertises GLP-1 from $119 a month. Every membership is a six-month non-cancelable contract, so the real minimum purchase is $714 to $2,514.
- Lighter You Review: The $99 That Buys Nothing2 sourcesLighter You advertises 'start for just $99'. No program on the site costs $99; the cheapest is $145, and the only route to a real price is behind a login.
How treatment plays out over time
What actually happens to your weight, and to the drug itself in your body, across weeks and months of treatment.
- Does GLP-1 Weight Loss Plateau? What the Physiology Shows3 sourcesWeight loss on Wegovy or Zepbound levels off, and that's not the drug failing. What a 2024 modeling study found about why, versus diet and surgery.
- How Long GLP-1 Drugs Stay in Your System4 sourcesSemaglutide and tirzepatide clear over weeks, not hours. The half-life figures from each FDA label, and what they mean for surgery and pregnancy planning.
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