Complete Guide to Prescription Weight-Loss Medications (Including the New GLP-1/GLP-1-GIP Injections)

Some patients need more than diet and exercise. Under physician supervision, anti-obesity medications (AOMs) can improve appetite control, cravings, fullness, and metabolic health. Below is a clear, clinic-ready overview—what they are, how they work, who might qualify, and key cautions. W8MD’s Philadelphia team can evaluate and prescribe when appropriate.

A) Incretin-Based Injections (Newest & Most Effective for Many)

Tirzepatide — Zepbound® (weight management) / Mounjaro® (type 2 diabetes)

• Class/Mechanism: Dual GLP-1 + GIP receptor agonist; powerful appetite and weight-loss effects.

• Dosing: Once weekly; gradual titration to improve GI tolerability.

• Common Effects: Nausea, diarrhea/constipation, abdominal discomfort—usually during dose increases.

• Key Cautions: Not for pregnancy; avoid with personal/family history of medullary thyroid carcinoma or MEN2; use caution if history of pancreatitis or gallbladder disease.

Semaglutide — Wegovy® (weight management) / Ozempic® (type 2 diabetes)

• Class/Mechanism: GLP-1 receptor agonist; robust weight loss and improved satiety.

• Dosing: Once weekly; dose-escalation per label.

• Common Effects/Cautions: Similar to tirzepatide (see above).

Liraglutide — Saxenda® (weight management) / Victoza® (type 2 diabetes)

• Class/Mechanism: GLP-1 receptor agonist.

• Dosing: Once-daily injection with gradual up-titration.

• Common Effects/Cautions: Similar GLP-1 class effects.

Who may qualify (typical criteria): Adults with BMI ≥30, or BMI ≥27 with a weight-related condition (e.g., high BP, dyslipidemia, type 2 diabetes), plus readiness for a reduced-calorie diet and increased activity.

B) Combination & Oral Agents

Phentermine/Topiramate ER — Qsymia®

• Mechanism: Sympathomimetic (appetite suppression) + anticonvulsant (craving/portion control).

• Pros: Strong efficacy when paired with meal structure and follow-up.

• Common Effects: Dry mouth, paresthesias (tingling), altered taste, insomnia, constipation.

• Key Cautions: Teratogenic—requires reliable contraception and periodic pregnancy testing; caution with glaucoma, kidney stones, mood/cognitive effects.

Naltrexone/Bupropion SR — Contrave®

• Mechanism: Targets reward/craving pathways and appetite centers.

• Common Effects: Nausea, headache, insomnia; avoid with seizure disorders, chronic opioid therapy, uncontrolled hypertension.

Orlistat — Xenical®/Alli®

• Mechanism: Inhibits GI fat absorption.

• Common Effects: GI oiliness, urgency; take fat-soluble vitamin supplements (A/D/E/K) separated in time.

Plenity® (Hydrogel Device)

• Mechanism: Cellulose/citric-acid hydrogel taken before meals; expands in the stomach to enhance fullness.

• Note: Not a systemic drug; works with diet and behavior changes.

C) Short-Term Sympathomimetics (Appetite Suppressants)

Phentermine

• Use: Short-term adjunct to a structured program.

• Common Effects: Elevated BP/HR, insomnia, anxiety/irritability, dry mouth, constipation.

• Cautions: Avoid in pregnancy, hyperthyroidism, glaucoma, MAOI use, certain cardiac conditions; monitor BP/HR, mood, and sleep.

Diethylpropion & Phendimetrazine

• Use/Notes: Similar to phentermine; short-term use only with monitoring due to side-effect profile.

D) Specialized / Genetic-Obesity Option

Setmelanotide — Imcivree®

• Indication: Certain rare genetic forms of obesity (e.g., POMC, LEPR, PCSK1 deficiency).

• Use: Requires genetic confirmation and specialist oversight.

How W8MD’s Philadelphia Program Uses Medications—Safely

• Full medical evaluation (history, meds, labs, sleep screening) to uncover causes of weight gain (e.g., insulin resistance, sleep apnea, meds that add weight).

• Nutrition first: Protein-forward, high-fiber, low-glycemic or keto-friendly plans; LCD/VLCD options only under supervision; optional meal replacements for precision and convenience.

• Behavior coaching: Meal timing, dining out, travel, stress/sleep routines, relapse-prevention.

• Medication stewardship: We match the right agent to your profile, titrate thoughtfully, manage side effects, and help explore insurance coverage or alternatives when needed.

• Follow-ups & maintenance: Adjust calories/macros, activity, and medications as your body changes.

• Sleep integration: Testing/treatment for snoring/OSA/insomnia to remove hidden blockers.

Important safety notes for all AOMs: Not for pregnancy; review for drug interactions and contraindications; report severe abdominal pain, persistent vomiting, or signs of gallbladder/pancreatic issues promptly. Always use FDA-approved products as prescribed.

Not Sure Which Option Fits You?

The “best” medication depends on your medical history, current meds, side-effect tolerance, preferences, and coverage. Many patients succeed on nutrition + behavior + movement, while others benefit from adding a GLP-1/GLP-1-GIP agent or a combination oral.

Ready to Be Evaluated?

W8MD Medical Weight Loss & Sleep – Philadelphia (Primary)
1718 Welsh Road, 2nd Floor, Ste C
Philadelphia, PA 19115 • (215) 676-2334

W8MD – New York City
2632 East 21st Street, Ste L3
Brooklyn, NY 11235 • (718) 946-5500

Less commonly used and investigational weight loss medications

Obocell: Obocell is a drug that is being developed for the treatment of obesity. It is thought to work by inhibiting the production of an enzyme called carboxylesterase, which is involved in the breakdown of fat in the body. The safety and efficacy of Obocell for weight loss have not yet been established in clinical trials.

2,4-Dinitrophenol: 2,4-Dinitrophenol is a chemical compound that was once used as a weight loss medication. However, it has been withdrawn from the market due to its dangerous side effects and high potential for toxicity. 2,4-Dinitrophenol works by increasing the body’s metabolic rate, but it can cause serious side effects, including heart problems, muscle weakness, and even death.
AdipoRon: AdipoRon is a weight loss medication that works by targeting a protein called adiponectin, which regulates glucose metabolism and fatty acid oxidation. It is still in the experimental stage and has only been tested in animal studies so far. While it has shown promising results in reducing body weight, more research is needed to determine its safety and efficacy in humans.
Anti-obesity medication: Anti-obesity medications are prescription drugs used for weight loss and management. These medications work by reducing appetite, increasing metabolism, or blocking the absorption of fat. Anti-obesity medications should be used under the close supervision of a doctor and only as part of a comprehensive weight loss program that includes lifestyle changes, such as diet and exercise.
Azalanstat: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by blocking the production of a specific hormone involved in the regulation of metabolism and body weight.
Beloranib: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by blocking the production of a specific hormone involved in the regulation of metabolism and body weight.
Benfluorex: Benfluorex is a medication used for weight loss that was once available in Europe. However, it has been withdrawn from the market due to its dangerous side effects, including heart problems and an increased risk of blood clots
Benfluorex: This was a weight loss medication that was available in Europe, but has been withdrawn from the market due to concerns about its safety.
Benzphetamine: Benzphetamine is a prescription medication used for weight loss. It is classified as an anorectic drug, meaning it reduces appetite. Benzphetamine works by increasing the release of certain chemicals in the brain that suppress hunger. It should only be used under the close supervision of a doctor, as it has the potential for abuse and can cause serious side effects.
Bupropion/zonisamide: This combination drug is being investigated for its potential use in the treatment of obesity. Zonisamide is an anticonvulsant that is thought to promote weight loss by reducing food intake, while bupropion increases feelings of fullness.
Bupropion: Bupropion is an antidepressant medication that is also used for weight loss. It works by increasing the levels of certain chemicals in the brain that are involved in regulating appetite. Bupropion is usually prescribed in combination with other weight loss medications and should be used under the close supervision of a doctor.
Cetilistat: This is a drug that blocks the action of lipases, which are enzymes involved in the breakdown of fat in the body. By reducing the breakdown of fat, cetilistat may promote weight loss.
Dexfenfluramine: Dexfenfluramine was once a popular weight loss medication, but it has since been withdrawn from the market due to its dangerous side effects. Dexfenfluramine works by increasing the release of serotonin, a chemical in the brain that regulates hunger. It was linked to serious health problems, including heart valve problems, and is no longer available for use.
Dirlotapide: Dirlotapide is a prescription medication used for weight loss in animals. It works by reducing the absorption of fat in the gut, but it is not yet approved for use in humans. Dirlotapide is being studied for its potential as a weight loss medication, but more research is needed to determine its safety and effectiveness.
Dirlotapide: This is a drug that blocks the absorption of fat in the intestines. It is used in the treatment of obesity, but has been associated with serious side effects, including heart problems and liver damage.
Etiocholanedione: Etiocholanedione is a steroid hormone that has been studied for its potential use as a weight loss medication. It is believed to increase energy expenditure and lipid metabolism, leading to weight loss. However, research is still in its early stages, and more studies are needed to determine its safety and effectiveness as a weight loss medication.
Etiocholanedione: Etiocholanedione is a steroidal anti-obesity medication that works by reducing the uptake of glucose from the bloodstream and increasing insulin sensitivity. It is still in the experimental stage and has only been tested in animal studies so far. While it has shown promising results in reducing body weight, more research is needed to determine its safety and efficacy in humans.
Etiocholanedione: Etiocholanedione is a steroidal compound that is being studied for its potential to promote weight loss. It is thought to work by increasing the expression of certain genes involved in fat metabolism, but its safety and efficacy for weight loss have not yet been established in clinical trials.
Fenbutrazate: This is a weight loss medication that has been shown to reduce the formation of fat cells in the body. It works by blocking the action of a specific enzyme involved in the synthesis of fat.
Fluasterone: Fluasterone is a selective androgen receptor modulator (SARM) that is being studied for its potential to promote weight loss. It is thought to work by increasing muscle mass and reducing fat mass, but its safety and efficacy for weight loss have not yet been established in clinical trials.
Fluasterone: Fluasterone is a steroid hormone that has been studied for its potential use as a weight loss medication. It is believed to increase energy expenditure and lipid metabolism, leading to weight loss. However, research is still in its early stages, and more studies are needed to determine its safety and effectiveness as a weight loss medication.
Fluasterone: Fluasterone is an anabolic steroid that has been studied for its potential as an anti-obesity medication. It works by increasing muscle mass and decreasing fat mass, leading to improved body composition. However, the use of anabolic steroids for weight loss is controversial and may lead to serious side effects, including liver damage, cardiovascular disease, and hormonal imbalances. As such, it is not recommended as a weight loss treatment option.

Lorcaserin: Withdrawn from the market in the United States. This is a weight loss medication that works by targeting serotonin receptors in the brain. It is thought to reduce food intake by increasing feelings of fullness and decreasing hunger.
Mitratapide: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by blocking the production of a specific hormone involved in the regulation of metabolism and body weight.
Obocell: Obocell is a weight loss medication that is currently in development. It works by blocking the absorption of dietary fats in the gut, leading to a decrease in calorie intake and weight loss. It is still in the early stages of development and more research is needed to determine its safety and efficacy as a weight loss medication.
Obocell: Obocell is a weight loss medication that works by targeting the obesity-related gene called PTP1B. It is still in the experimental stage and has only been tested in animal studies so far. While it has shown promising results in reducing body weight and improving insulin sensitivity, more research is needed to determine its safety and efficacy in humans.
Oleoyl-estrone: Oleoyl-estrone is a naturally occurring substance that has been studied for its potential as a weight loss medication. It works by regulating the metabolism and suppressing appetite, but more research is needed to determine its safety and effectiveness. Oleoyl-estrone is not yet available as a prescription medication.
Oleoyl-estrone: This is a naturally occurring compound found in olive oil. Some studies have suggested that oleoyl-estrone may promote weight loss by increasing the breakdown of fat in the body and reducing the formation of fat cells. However, more research is needed to fully understand the effects of oleoyl-estrone on weight loss.
Orlistat: Orlistat is a medication used for weight loss and management. It works by blocking the absorption of dietary fats, which helps to reduce caloric intake and promote weight loss. Orlistat is available over-the-counter or by prescription and is typically taken with each meal to maximize its effectiveness.
Prohibitin-targeting peptide 1: This is a drug that is being investigated for
Tesofensine: This is a drug that is currently being investigated for its potential use in the treatment of obesity. It works by reducing the absorption of fat in the intestines and increasing feelings of fullness. However, further research is needed to determine its safety and efficacy for weight loss.
Vabicaserin: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by targeting serotonin receptors in the brain, which are involved in the regulation of appetite.
This is a comprehensive list of weight loss medications, but it is important to note that the safety and efficacy of many of these drugs have not been established. Before starting any weight loss medication, it is important to consult with a healthcare professional to assess its potential benefits and risks for each individual.

New FDA approved weight loss injections

Semaglutide (Wegovy): Semaglutide is a medication that is commonly used to treat type 2 diabetes but has also been studied for its potential as a weight loss medication. It works by increasing feelings of fullness and reducing food intake, leading to weight loss. While semaglutide has been shown to be effective for weight loss in clinical trials, more research is needed to determine its long-term safety and efficacy.

Liraglutide (Saxenda): This is a drug that is used to treat type 2 diabetes, but has also been shown to promote weight loss in some individuals. It works by increasing feelings of fullness and reducing the desire to eat.

Phendimetrazine: Phendimetrazine is a prescription medication used for weight loss and management. It is classified as an anorectic drug and works by increasing the release of certain chemicals in the brain that suppress hunger. Phendimetrazine should only be used under the close supervision of a doctor and for a limited period of time due to the potential for abuse and serious side effects.
Phentermine/topiramate: This is a combination drug used to treat obesity. Phentermine is a stimulant that decreases appetite, while topiramate is an anticonvulsant that is thought to promote weight loss by reducing food cravings.

Naltrexone/bupropion (Contrave): This combination drug is used to treat obesity. Naltrexone is an opioid antagonist that reduces the desire to eat, while bupropion is an antidepressant that increases feelings of fullness.

Obocell: Obocell is a drug that is being developed for the treatment of obesity. It is thought to work by inhibiting the production of an enzyme called carboxylesterase, which is involved in the breakdown of fat in the body. The safety and efficacy of Obocell for weight loss have not yet been established in clinical trials.

2,4-Dinitrophenol: 2,4-Dinitrophenol is a chemical compound that was once used as a weight loss medication. However, it has been withdrawn from the market due to its dangerous side effects and high potential for toxicity. 2,4-Dinitrophenol works by increasing the body’s metabolic rate, but it can cause serious side effects, including heart problems, muscle weakness, and even death.
AdipoRon: AdipoRon is a weight loss medication that works by targeting a protein called adiponectin, which regulates glucose metabolism and fatty acid oxidation. It is still in the experimental stage and has only been tested in animal studies so far. While it has shown promising results in reducing body weight, more research is needed to determine its safety and efficacy in humans.
Anti-obesity medication: Anti-obesity medications are prescription drugs used for weight loss and management. These medications work by reducing appetite, increasing metabolism, or blocking the absorption of fat. Anti-obesity medications should be used under the close supervision of a doctor and only as part of a comprehensive weight loss program that includes lifestyle changes, such as diet and exercise.
Azalanstat: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by blocking the production of a specific hormone involved in the regulation of metabolism and body weight.
Beloranib: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by blocking the production of a specific hormone involved in the regulation of metabolism and body weight.
Benfluorex: Benfluorex is a medication used for weight loss that was once available in Europe. However, it has been withdrawn from the market due to its dangerous side effects, including heart problems and an increased risk of blood clots
Benfluorex: This was a weight loss medication that was available in Europe, but has been withdrawn from the market due to concerns about its safety.
Benzphetamine: Benzphetamine is a prescription medication used for weight loss. It is classified as an anorectic drug, meaning it reduces appetite. Benzphetamine works by increasing the release of certain chemicals in the brain that suppress hunger. It should only be used under the close supervision of a doctor, as it has the potential for abuse and can cause serious side effects.
Bupropion/zonisamide: This combination drug is being investigated for its potential use in the treatment of obesity. Zonisamide is an anticonvulsant that is thought to promote weight loss by reducing food intake, while bupropion increases feelings of fullness.
Bupropion: Bupropion is an antidepressant medication that is also used for weight loss. It works by increasing the levels of certain chemicals in the brain that are involved in regulating appetite. Bupropion is usually prescribed in combination with other weight loss medications and should be used under the close supervision of a doctor.
Cetilistat: This is a drug that blocks the action of lipases, which are enzymes involved in the breakdown of fat in the body. By reducing the breakdown of fat, cetilistat may promote weight loss.
Dexfenfluramine: Dexfenfluramine was once a popular weight loss medication, but it has since been withdrawn from the market due to its dangerous side effects. Dexfenfluramine works by increasing the release of serotonin, a chemical in the brain that regulates hunger. It was linked to serious health problems, including heart valve problems, and is no longer available for use.
Dirlotapide: Dirlotapide is a prescription medication used for weight loss in animals. It works by reducing the absorption of fat in the gut, but it is not yet approved for use in humans. Dirlotapide is being studied for its potential as a weight loss medication, but more research is needed to determine its safety and effectiveness.
Dirlotapide: This is a drug that blocks the absorption of fat in the intestines. It is used in the treatment of obesity, but has been associated with serious side effects, including heart problems and liver damage.
Etiocholanedione: Etiocholanedione is a steroid hormone that has been studied for its potential use as a weight loss medication. It is believed to increase energy expenditure and lipid metabolism, leading to weight loss. However, research is still in its early stages, and more studies are needed to determine its safety and effectiveness as a weight loss medication.
Etiocholanedione: Etiocholanedione is a steroidal anti-obesity medication that works by reducing the uptake of glucose from the bloodstream and increasing insulin sensitivity. It is still in the experimental stage and has only been tested in animal studies so far. While it has shown promising results in reducing body weight, more research is needed to determine its safety and efficacy in humans.
Etiocholanedione: Etiocholanedione is a steroidal compound that is being studied for its potential to promote weight loss. It is thought to work by increasing the expression of certain genes involved in fat metabolism, but its safety and efficacy for weight loss have not yet been established in clinical trials.
Fenbutrazate: This is a weight loss medication that has been shown to reduce the formation of fat cells in the body. It works by blocking the action of a specific enzyme involved in the synthesis of fat.
Fluasterone: Fluasterone is a selective androgen receptor modulator (SARM) that is being studied for its potential to promote weight loss. It is thought to work by increasing muscle mass and reducing fat mass, but its safety and efficacy for weight loss have not yet been established in clinical trials.
Fluasterone: Fluasterone is a steroid hormone that has been studied for its potential use as a weight loss medication. It is believed to increase energy expenditure and lipid metabolism, leading to weight loss. However, research is still in its early stages, and more studies are needed to determine its safety and effectiveness as a weight loss medication.
Fluasterone: Fluasterone is an anabolic steroid that has been studied for its potential as an anti-obesity medication. It works by increasing muscle mass and decreasing fat mass, leading to improved body composition. However, the use of anabolic steroids for weight loss is controversial and may lead to serious side effects, including liver damage, cardiovascular disease, and hormonal imbalances. As such, it is not recommended as a weight loss treatment option.

Lorcaserin: Withdrawn from the market in the United States. This is a weight loss medication that works by targeting serotonin receptors in the brain. It is thought to reduce food intake by increasing feelings of fullness and decreasing hunger.
Mitratapide: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by blocking the production of a specific hormone involved in the regulation of metabolism and body weight.
Obocell: Obocell is a weight loss medication that is currently in development. It works by blocking the absorption of dietary fats in the gut, leading to a decrease in calorie intake and weight loss. It is still in the early stages of development and more research is needed to determine its safety and efficacy as a weight loss medication.
Obocell: Obocell is a weight loss medication that works by targeting the obesity-related gene called PTP1B. It is still in the experimental stage and has only been tested in animal studies so far. While it has shown promising results in reducing body weight and improving insulin sensitivity, more research is needed to determine its safety and efficacy in humans.

Oleoyl-estrone: Oleoyl-estrone is a naturally occurring substance that has been studied for its potential as a weight loss medication. It works by regulating the metabolism and suppressing appetite, but more research is needed to determine its safety and effectiveness. Oleoyl-estrone is not yet available as a prescription medication.
Oleoyl-estrone: This is a naturally occurring compound found in olive oil. Some studies have suggested that oleoyl-estrone may promote weight loss by increasing the breakdown of fat in the body and reducing the formation of fat cells. However, more research is needed to fully understand the effects of oleoyl-estrone on weight loss.
Orlistat: Orlistat is a medication used for weight loss and management. It works by blocking the absorption of dietary fats, which helps to reduce caloric intake and promote weight loss. Orlistat is available over-the-counter or by prescription and is typically taken with each meal to maximize its effectiveness.
Prohibitin-targeting peptide 1: This is a drug that is being investigated for
Semaglutide: Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist that promotes weight loss by reducing appetite and increasing feelings of fullness. It is an injectable medication that is taken once weekly. Semaglutide has been shown to result in significant weight loss in clinical trials and has been approved for the treatment of obesity by regulatory agencies in several countries.
Tesofensine: This is a drug that is currently being investigated for its potential use in the treatment of obesity. It works by reducing the absorption of fat in the intestines and increasing feelings of fullness. However, further research is needed to determine its safety and efficacy for weight loss.
Vabicaserin: This is a drug that is being investigated for its potential use in the treatment of obesity. It works by targeting serotonin receptors in the brain, which are involved in the regulation of appetite.
This is a comprehensive list of weight loss medications, but it is important to note that the safety and efficacy of many of these drugs have not been established. Before starting any weight loss medication, it is important to consult with a healthcare professional to assess its potential benefits and risks for each individual.