Evidence
Evidence-based research
Every claim on WeighLab is tied to primary research or official labeling. Every claim on GLP-1 cost and efficacy, 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.
54 explainers · 195 primary sources cited
Looking for a specific company rather than the science? All 529 providers we have modeled are in the provider review index, and the ranked shortlists are on the rankings page.
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54 explainers across 11 topics
What a GLP-1 actually costs
Cash prices, the gap between a sticker and a year, and what the first month hides.
- How Much Does a GLP-1 Cost Without Insurance?8 sourcesThe real 2026 cash-pay price of GLP-1s without insurance — brand self-pay vials, compounded, and telehealth — and how to pay the least for the same result.
- What Compounded GLP-1 Actually Costs Per Month2 sourcesA cost guide to compounded semaglutide and tirzepatide: real disclosed ranges of roughly $65–$349/mo, what drives the spread, and how to model your own number.
- The True Monthly Cost of GLP-1: Beyond the Sticker Price2 sourcesTeaser step-ups, dose escalation, and hidden fees mean your real GLP-1 cost is rarely the landing-page number. How to calculate what you'll actually pay.
- GLP-1 Insurance Coverage and Prior Authorization, Explained3 sourcesWhy most GLP-1 prescriptions still need prior authorization, what plans typically require to approve one, and the two real coverage levers most people miss.
- Does Insurance Cover Zepbound or Wegovy? Aetna, Cigna, UHC, BCBS, Kaiser, Tricare and Medicare, Compared9 sourcesWhat Aetna, Cigna, UnitedHealthcare, BCBS, Kaiser, Tricare and Medicare publish on covering Zepbound and Wegovy — sourced to each payer's own current policy.
Compounded vs brand-name
The price difference, the legal framework behind it, and what the FDA does and does not verify.
- Compounded vs Brand-Name GLP-1: The Real Cost Difference5 sourcesWegovy and Zepbound list near $1,000+/mo; compounded semaglutide and tirzepatide run roughly $65–$349. What you trade for the gap, in dollars and oversight.
- Is Compounded Semaglutide Legit and Safe?3 sourcesA measured look at compounded semaglutide: 503A vs 503B pharmacies, LegitScript, the FDA shortage rules, and how to tell a legitimate provider from a risky one.
How a GLP-1 actually works — and what doesn't
The real mechanism behind the drug class, what's actually in the pen, and an honest look at the patches, pills and supplements marketed as a substitute.
- How Does a GLP-1 Work? The Actual Pharmacology Behind Zepbound and Wegovy5 sourcesGLP-1s don't just curb appetite by magic. Here's the actual pharmacology — gut hormones, brain receptors, gastric emptying — behind why they cause weight loss.
- What Is Actually in an Ozempic Pen?2 sourcesThe exact ingredients in an Ozempic pen, straight from the FDA-approved label — semaglutide plus its inactive ingredients, and what each one does.
- Is Phentermine a GLP-1? Contrave, Jardiance, and Farxiga, Too5 sourcesNone of these four common weight-loss and diabetes drugs are GLP-1s. Here's each one's actual FDA-labeled drug class and mechanism, straight from the label.
- Do GLP-1 Weight Loss Patches Work? What the Science Says3 sourcesGLP-1 patches on Amazon and TikTok Shop don't contain semaglutide or tirzepatide — and a molecule that size can't cross skin via a patch anyway.
- Does Berberine Work Like Ozempic? The Evidence on 'Natural Ozempic'8 sourcesBerberine is nicknamed 'natural Ozempic' online, but its studied mechanism is AMPK activation, not GLP-1 receptor agonism. Here's what the trials show.
Choosing the provider and the dose
Vetting an operator and following the labeled schedule once you've picked a molecule.
- How to Choose a GLP-1 Telehealth Provider: A Buyer's Checklist3 sourcesFive checks before you pay: price transparency, states served, molecule options, clinical oversight, and cancellation terms — the value-first way to pick.
- GLP-1 Dosing & Titration Schedules: Semaglutide vs Tirzepatide4 sourcesThe exact FDA-labeled dosing schedules for Wegovy (semaglutide) and Zepbound (tirzepatide) — starting dose, each step-up, and the maintenance range.
- Switching From Semaglutide to Tirzepatide: What Actually Happens3 sourcesThere's no FDA-published conversion chart between semaglutide and tirzepatide. Here's what the switching evidence, dosing math, and cost math actually say.
- Tirzepatide & Semaglutide: Converting mg Doses to Syringe Units2 sourcesHow to convert a compounded tirzepatide or semaglutide mg dose into units on a U-100 syringe — and why your vial's own concentration is what actually matters.
Comparing the GLP-1 drugs and brands
Same drug class, different molecules, doses and brand names — where the real differences, and the real prices, actually are.
- Semaglutide vs Tirzepatide: Which GLP-1 Costs Less and Works Better?4 sourcesTirzepatide wins on average weight loss in trials; semaglutide often wins on price. How to weigh efficacy against cost-per-month and pick the better value.
- Oral Semaglutide: Rybelsus, Ozempic Tablets and the Wegovy Pill, Explained4 sourcesThree different FDA-approved oral semaglutide tablets exist, at three different doses, for two different purposes. Here's what actually separates them.
- Zepbound vs Wegovy: Dose, Approved Uses and Cost Compared4 sourcesZepbound (tirzepatide) and Wegovy (semaglutide) are different molecules with different FDA-approved uses. Here's what each label, trial and price actually says.
- Mounjaro vs Zepbound: The Same Drug, a Different Label and a Very Different Price2 sourcesMounjaro and Zepbound are both tirzepatide at the same max dose — but one is priced like a diabetes drug and one like a weight-loss drug.
- Saxenda vs Wegovy: Liraglutide vs Semaglutide, Compared Head-to-Head5 sourcesSaxenda (daily liraglutide) was the GLP-1 weight-loss standard before Wegovy. The head-to-head trial shows exactly how much ground semaglutide gained.
- Ozempic vs Wegovy: Same Molecule, Different Approval, Different Bill3 sourcesOzempic and Wegovy are both semaglutide, but they're FDA-approved for different conditions, dosed differently, and covered by insurance very differently.
Side effects, safety and stopping
What the pivotal trials and dedicated safety reviews actually report — GI effects, body composition, and what happens when treatment ends.
- Tirzepatide Side Effects: What the Trials Actually Report4 sourcesReal adverse-event rates for tirzepatide (Zepbound/Mounjaro) from its pivotal trials — GI effects, discontinuation rates, and what the label flags.
- Semaglutide Side Effects: What the Trials Actually Report4 sourcesReal adverse-event rates for semaglutide (Wegovy/Ozempic) from its pivotal trials — GI effects, discontinuation, and long-term cardiovascular safety data.
- Does Semaglutide or Tirzepatide Cause Muscle Loss?3 sourcesWhat body-composition studies find: GLP-1 weight loss includes real lean-mass loss, roughly how much, and what mitigates it — resistance training and protein.
- What Happens When You Stop a GLP-1? Weight Regain, Explained3 sourcesThe actual trial data on weight regain after stopping a GLP-1, why it happens mechanistically, and the discontinuation strategies with real evidence.
- Does Tirzepatide or Semaglutide Make You Tired? What the FDA Data Shows5 sourcesFDA trial data on fatigue rates for Zepbound and Wegovy versus placebo, how the pattern differs from GI side effects, and the leading theories for why.
- Does Semaglutide or Tirzepatide Cause Cancer? The Thyroid Warning, Explained5 sourcesThe FDA's boxed thyroid C-cell tumor warning on semaglutide and tirzepatide comes from rodent studies, not confirmed human cases — here's the actual data.
- GLP-1s and Depression, Anxiety, and Mood Changes: What the Research Actually Shows4 sourcesThe FDA investigated GLP-1s and suicidal thoughts, then requested the warning be removed. Here's what that review and the mood-effect data actually found.
Interactions, life stage and organ-specific risk
What the label and the literature say about drinking, other medications, pregnancy and fertility, hair, skin, and the pancreas and gallbladder — beyond the standard GI-effects list.
- GLP-1 Drug and Alcohol Interactions: What Actually Interacts, and What Doesn't4 sourcesGLP-1s delay how the stomach absorbs other oral drugs — but the real interaction risks are narrower and more specific than the common assumptions.
- GLP-1s, Pancreatitis and Gallbladder Risk: What the Data Actually Shows4 sourcesThe FDA label warns about both. The trial and real-world data tells two different stories — gallbladder risk is real, pancreatitis risk is more complicated.
- GLP-1 Hair Loss: Is It the Drug, or the Weight Loss Itself?3 sourcesDermatology research links GLP-1s to hair loss, but causality isn't established — and the leading theory points at rapid weight loss, not the drug directly.
- GLP-1s and Pregnancy, Fertility and Breastfeeding: What the Labels and Research Actually Say4 sourcesGLP-1s can restore fertility and undermine oral contraceptives at the same time — and the breastfeeding rule differs by formulation, not by molecule.
- GLP-1s and Hormonal Birth Control: What the FDA Label Actually Requires3 sourcesTirzepatide's FDA label includes a specific instruction about oral contraceptives most patients never hear about until a pharmacist mentions it.
- "Ozempic Face": What Actually Causes GLP-1-Related Facial and Skin Changes3 sourcesFacial hollowing and skin laxity on a GLP-1 aren't a mystery — dermatology research explains it as fat and volume loss from rapid weight change.
Using a GLP-1 day to day
The practical mechanics after the prescription — how to inject, what the evidence says about doses below the labeled schedule, and what to do at a plateau.
- How to Inject Semaglutide: Sites, Technique and What the Label Actually Says3 sourcesWhere to inject, how to rotate sites, and what happens if you miss a dose — pulled directly from the FDA-approved instructions, not forum advice.
- GLP-1 Microdosing: What the Actual Dose-Response Data Shows2 sourcesNo trial has studied 'microdosing' as a strategy. But real dose-response data from the pivotal trials shows exactly what lower doses do and don't deliver.
- The GLP-1 Weight-Loss Plateau: Why It Happens and What the Evidence Says to Do4 sourcesA plateau while still on a GLP-1 differs from stopping the drug — trial data and new genetic research explain why it happens to some people and not others.
- Zepbound and Wegovy: Storage, Fridge Rules, and Travel6 sourcesThe exact FDA-label refrigeration windows for Zepbound and Wegovy pens, how many days each can sit at room temperature, and TSA rules for flying with them.
- How Long Does It Take for a GLP-1 to Start Working?6 sourcesSemaglutide and tirzepatide start acting within days, but trial data show it takes weeks, not hours, before weight loss is visible on the scale.
- How to Reconstitute Compounded Tirzepatide With Bacteriostatic Water1 sourceWhy some compounded tirzepatide vials ship as powder needing mixing, the concentration math, and why only your pharmacy's own instructions apply.
New molecules, new indications, and what's next
Drugs and uses moving through the pipeline right now — an FDA-approved second indication, an oral small-molecule contender, an investigational triple agonist, and emerging trial evidence outside weight loss.
- Zepbound for Sleep Apnea: What SURMOUNT-OSA Actually Showed3 sourcesZepbound is FDA-approved to treat moderate-to-severe obstructive sleep apnea in adults with obesity — a second indication with its own trial and coverage angle.
- Orforglipron (Foundayo): What the Once-Daily GLP-1 Pill Actually Is3 sourcesOrforglipron (Foundayo) is an FDA-approved once-daily oral GLP-1 pill — not a peptide like Rybelsus. What the trial data shows, and what it means for cost.
- Retatrutide vs Tirzepatide: The Investigational Triple Agonist, Compared Honestly3 sourcesRetatrutide's Phase 2 numbers beat tirzepatide's own trial — but it isn't FDA-approved, and the two have never been tested head-to-head.
- Can GLP-1s Reduce Alcohol Cravings? What the New Trial Evidence Shows3 sourcesA 2026 randomized controlled trial in The Lancet found semaglutide reduced heavy drinking in people with alcohol use disorder. What's proven, and what isn't.
Provider bench tests
One company at a time: the rung you can actually buy for a month, the rung the marketing would rather you filed, and every place a provider's own pages disagree with each other.
- The Edit Review: What $209 Semaglutide Costs Over a Year3 sourcesThe Edit publishes $209 semaglutide and $309 tirzepatide month-to-month, and its prepay math checks out to the dollar. The $109 you see first does not.
- Pepti Review: $99 Semaglutide, and the Ladder That Contradicts It2 sourcesPepti prices semaglutide at $99 flat at every dose. Its own production data carries a $299-$449 per-dose ladder nothing renders, and we could not break the tie.
- Trellis Vitality Review: A Real 1/3/6-Month Price Table3 sourcesTrellis Vitality publishes a real 1/3/6-month GLP-1 table with the monthly column labeled. Everything outside GLP-1 is a 'starting at' figure with no ladder.
- Auren Rx Review: Two Rungs on Every SKU, and Which One We File2 sourcesAuren Rx publishes a subscribe rung and a no-commitment rung for every product. Its page defaults to tirzepatide and its schema emits the cheaper number.
- Vyvron Review: Thirteen Charges a Year, Not Twelve2 sourcesVyvron prints $199/mo and bills every four weeks — thirteen charges a year. Its tirzepatide has no monthly rung at all; the cheapest entry is $790 prepaid.
- Rehydra+ Wellness Review: The $119 Month You Cannot Buy2 sourcesRehydra+ advertises GLP-1 memberships from $119 a month. Every one is a six-month non-cancelable contract, so the real minimum purchase is $714 to $2,514.
- Lighter You Review: Seven Price Strings and a Login Wall2 sourcesLighter You leads with $99 and sells nothing at $99 — its cheapest program is $145. Its whole public price surface is seven strings, and checkout needs a login.
Coverage, law, and what's actually legal
The statutes and regulations behind GLP-1 access — what Medicare, Medicaid and the tax code actually say, and the compounding rules that changed when tirzepatide came off the shortage list.
- Medicare, Medicaid, and HSA/FSA: The GLP-1 Rules the Federal Government Actually Sets4 sourcesFederal law explicitly excludes weight-loss drugs from routine Medicare and Medicaid coverage — but three real, citable exceptions exist.
- Is Compounded Tirzepatide Still Legal?3 sourcesTirzepatide's mass-compounding shortage exception is time-limited by statute. Here's exactly what's still legal, and what changed.