What are weight-loss medications?
Modern prescription weight-loss medications are dominated by the GLP-1 receptor agonists— a class of injectable (and one oral) drugs that mimic glucagon-like peptide-1, a hormone your small intestine releases after you eat. By activating GLP-1 receptors throughout the body, they lower blood sugar, slow how fast your stomach empties, and signal fullness to the brain. The result is substantial appetite reduction and weight loss — which is why “weight-loss shot”, “weight-loss injection” and “GLP-1” have become nearly synonymous.
First developed for type 2 diabetes in the late 2000s, the class transformed weight management once semaglutide (Wegovy) and tirzepatide (Zepbound) earned FDA approval for chronic weight management, producing results previously only seen with bariatric surgery.
GLP-1 drugs list
The current GLP-1 (and dual GLP-1/GIP) landscape:
Want the pharmacology-first view? Our GLP-1 agonists comparison guide compares every agonist by mechanism, dosing, and efficacy.
Weight-loss injections vs. weight-loss pills
Most weight-loss medication today is an injection — a once-weekly shot (Wegovy, Zepbound, Ozempic, Mounjaro) or daily shot (Saxenda) you give yourself with a small pen or vial. The leading pill options are Rybelsus (oral semaglutide for diabetes) and, since 2026, two FDA-approved oral weight-loss pills — the Wegovy pill (oral semaglutide, launched Jan 2026) and Foundayo (orforglipron, approved Apr 2026). The largest average weight loss is still from injectables, but pills have arrived. See our oral GLP-1 pills guide.
How do GLP-1 medications work?
GLP-1 receptor agonists work through four mechanisms:
- Glucose-dependent insulin release. They stimulate the pancreas to release insulin only when blood sugar is elevated — reducing hypoglycemia risk vs older diabetes drugs.
- Glucagon suppression. They lower glucagon (the hormone that raises blood sugar), further improving glucose control.
- Slowed gastric emptying. Food stays in your stomach longer → you feel full longer → you eat less.
- Central appetite regulation. They act on hypothalamic appetite centers to reduce hunger and “food noise” — the constant intrusive thoughts about food.
Tirzepatide (Mounjaro, Zepbound) adds a fifth mechanism: it also activates GIP (glucose-dependent insulinotropic polypeptide) receptors, which may explain its greater weight-loss efficacy.
How much weight can you lose?
In pivotal trials, average weight loss at the top maintenance dose was about 21% with tirzepatide (SURMOUNT-1, 72 weeks), 15% with semaglutide 2.4 mg (STEP-1, 68 weeks), and ~8% with liraglutide (SCALE, 56 weeks). Individual results vary widely with dose, diet, activity, and how long you stay on treatment. See the live outcome data and compare two drugs directly in our semaglutide vs tirzepatide breakdown.
GLP-1 side effects
The most common side effects are gastrointestinal and usually mild-to-moderate, improving as your body adjusts:
- Nausea — most common (~20-44%), peaks during dose increases
- Vomiting, diarrhea, constipation — common, manageable
- Abdominal pain, indigestion — common early
- Injection-site reactions — mild, transient
Rare but serious risks include pancreatitis, gallbladder disease, and (in animal studies) a thyroid-tumor signal that places a boxed warning on most GLP-1 labels — discuss personal and family medical history with your prescriber. Slow dose titration is the single best tactic for minimizing GI side effects. See per-drug detail on any medication page.
How much do weight-loss medications cost?
Without insurance, brand GLP-1s run $1,000-1,349/month at list price. Manufacturer cash-pay programs cut that — Zepbound vials from ~$349/month and Wegovy from ~$349/month (with a ~$199/month introductory offer) as of mid-2026. Compounded semaglutide and tirzepatide via telehealth cost $150-400/month cash-pay — but are not FDA-approved as finished products. With insurance, copays range $0-300 depending on plan and indication. Use our cost calculator for a personalized estimate, find the cheapest GLP-1 options, or check provider coverage by state.
How to get weight-loss medication
You need a prescription from a licensed clinician. The common routes are: your primary-care doctor or an obesity-medicine specialist; or a telehealth provider that evaluates you online and ships from a partner pharmacy. Eligibility for the weight-management brands generally requires a BMI ≥30 (or ≥27 with a weight-related condition). Not sure where to start? Take our 60-second quiz to match with a medication and provider, or compare the top telehealth providers.
Other (non-GLP-1) weight-loss medications
GLP-1s are the most effective options, but older prescription weight-loss drugs remain in use and may suit some people or budgets:
- Phentermine. Short-term appetite suppressant (stimulant); decades of use, low cost.
- Qsymia (phentermine/topiramate). Combination pill; ~9% average weight loss.
- Contrave (naltrexone/bupropion). Combination pill targeting appetite and cravings; ~5%.
- Orlistat (Alli/Xenical). Blocks dietary-fat absorption; OTC and prescription; modest effect.
These are covered for completeness; GLP-1 medications produce substantially more weight loss in trials, which is why they dominate prescribing today.
Who are weight-loss medications for?
FDA-approved candidates: adults with type 2 diabetes (Ozempic, Mounjaro, Rybelsus), or adults with BMI ≥30 (or ≥27 with a weight-related comorbidity like hypertension, sleep apnea, or cardiovascular disease) for weight management (Wegovy, Zepbound, Saxenda). Not for type 1 diabetes, pregnancy, or those with personal/family history of medullary thyroid carcinoma or MEN2.
Frequently asked questions
What is the best weight-loss medication?
In head-to-head trial data, tirzepatide (Zepbound) produced the greatest average weight loss — about 21% of body weight at 72 weeks in SURMOUNT-1 — ahead of semaglutide (Wegovy) at about 15% in STEP-1. "Best" still depends on your health profile, insurance, tolerance to side effects, and whether you prefer an injection or a pill, so the right choice is individual and made with a prescriber.
What is the best weight-loss injection or shot?
The two most effective weight-loss shots are tirzepatide (Zepbound, ~21% average weight loss) and semaglutide (Wegovy, ~15%), both once-weekly injections. Liraglutide (Saxenda) is a daily injection with a smaller average effect (~8%). Compounded semaglutide and tirzepatide deliver the same active ingredients at lower cash prices but are not FDA-approved as finished products.
What are GLP-1 medications?
GLP-1 (glucagon-like peptide-1) receptor agonists are a class of medications that mimic the GLP-1 hormone your gut releases after eating. They lower blood sugar, slow gastric emptying, and reduce appetite. Originally developed for type 2 diabetes, several are now FDA-approved for chronic weight management.
What is the GLP-1 drugs list?
FDA-approved GLP-1 (and GLP-1/GIP) medications include: Ozempic, Rybelsus and Wegovy (semaglutide); Mounjaro and Zepbound (tirzepatide); Saxenda and Victoza (liraglutide); Trulicity (dulaglutide); Byetta and Bydureon (exenatide). Compounded semaglutide and tirzepatide are also widely used via telehealth.
How much do weight-loss medications cost?
Without insurance, brand GLP-1s list at roughly $1,000–$1,349/month. Manufacturer cash-pay programs lower that (Zepbound vials from ~$349/month, Wegovy from ~$349/month as of mid-2026). Compounded semaglutide and tirzepatide via telehealth run about $150–$400/month. With insurance, copays range $0–$300 depending on plan and indication.
How do GLP-1 medications work?
GLP-1 drugs activate GLP-1 receptors to: (1) stimulate insulin release when blood sugar is high, (2) suppress glucagon (which raises blood sugar), (3) slow gastric emptying so you feel full longer, and (4) act on brain appetite centers to reduce hunger and "food noise". Tirzepatide also activates GIP receptors for added effect.
People also ask
Are weight-loss injections safe?
For appropriate candidates, GLP-1 weight-loss injections have a well-characterized safety profile across multi-year trials. The most common effects are gastrointestinal (nausea, vomiting, diarrhea, constipation), usually mild-to-moderate and improving with slow dose titration. Rare but serious risks include pancreatitis and gallbladder disease, and the labels carry a boxed thyroid-tumor warning derived from rodent studies. They are avoided in pregnancy and in people with a personal/family history of medullary thyroid carcinoma or MEN2. Always review your history with a licensed prescriber.
What is the downside of GLP-1 medications?
The main downsides are: frequent GI side effects (nausea, vomiting, diarrhea, constipation), especially during dose increases; high cost without insurance ($1,000+/month for brand); the need for ongoing use — weight tends to return after stopping; muscle-mass loss alongside fat loss if protein and resistance training are neglected; and rare but serious risks like pancreatitis, gallbladder disease, and a boxed thyroid-tumor warning.
Do GLP-1 side effects go away?
For most people, yes. The common gastrointestinal side effects (nausea, diarrhea, constipation) are usually worst during the first weeks and after each dose increase, then ease as the body adapts — often within a few weeks to a couple of months. Slow dose titration, smaller meals, and staying hydrated reduce them. Side effects that are severe, persistent, or include intense abdominal pain warrant contacting your prescriber.
Who should not take GLP-1 medications?
GLP-1 drugs are generally avoided in people with a personal or family history of medullary thyroid carcinoma or MEN2 syndrome, a history of pancreatitis, type 1 diabetes, or known hypersensitivity. They are not recommended during pregnancy or breastfeeding and are used cautiously in those with severe gastrointestinal disease (e.g. gastroparesis). Always review your full medical history with a licensed prescriber.
How long do you stay on weight-loss medication?
GLP-1 medications are designed for long-term, ongoing use because obesity is a chronic condition. In trials, most people regain a substantial share of lost weight within a year of stopping. Some prescribers explore lower maintenance doses, but stopping generally leads to appetite and weight returning. Duration is an individual decision made with your clinician.