Semaglutide Vs Phentermine For Weight Loss: Facts Revealed

Welcome to the nitty-gritty showdown you didn’t know you needed: Semaglutide vs. Phentermine for weight loss.

With the many medications claiming to be your silver bullet, how do you pick your champion? This article is your compass, guiding you through the maze of effectiveness, side effects, and costs associated with Semaglutide and Phentermine. 

Stick around because we’ve also dug up some lesser-known facts that might tip the scales in your decision-making process. So, sit tight, and let’s unravel the facts!

What are Semaglutide and Phentermine?

Semaglutide and Phentermine are distinct weight-loss meds.

Semaglutide: Semaglutide is one of the most popular weight loss drugs known under its name, Ozempic, and Wegovy. You can also get compounded Semaglutide, which combines traditional Semaglutide with other body-safe vitamins, such as B6. 

This drug acts like a hormone you naturally have, called glucagon-like peptide-1 (GLP-1), which reins in your hunger and leaves you feeling content. The drug has been clinically shown to assist people in losing an average of 14.9% of their body weight. 

Phentermine: It’s an appetite-curbing stimulant and holds FDA approval for short-term use—up to 12 weeks—in obese adults. 

Phentermine, also sold under the names Suprenza and Adipex, curbs your hunger and aids in dropping pounds. You usually take it for a brief stint—about three months—and you could lose an average of 3% of your total body weight during that window.

Origin and uses

Initially crafted for type 2 diabetes treatment, Semaglutide gained FDA approval in 2017. It later ventured into the weight loss domain and scored FDA approval again in 2021.

Phentermine initially hit the scene in the 1950s as an antidepressant. Later, it was discovered to aid weight loss, and the FDA approved it in 1959.

FDA approval

The FDA gives the green light to Semaglutide for shedding pounds in adults burdened by obesity or extra weight and those in danger of health complications tied to their weight.

Conversely, Phentermine snagged the FDA’s nod for short-term weight loss in obese grown-ups but is a hard pass for extended use.

Semaglutide vs Phentermine: The Main Differences

Semaglutide and Phentermine are two commonly prescribed options in weight loss medications. Let us compare how these drugs function in the body, recommended dosage levels, the typical duration of treatment, and their relative effectiveness in promoting weight loss. Additionally, we’ll explore possible side effects, cost comparisons, and potential interactions with other medications.

How Do They Work?

Semaglutide is pretty sly, acting just like a hormone we’ve naturally got, dubbed glucagon-like peptide-1 (GLP-1). This little guy’s job? Keeping hunger in check and letting you know when the tank’s full. Semaglutide gets in on the action by latching onto GLP-1 hotspots in our brain and gut. When these spots light up, your brain gets the memo: “Belly’s full; put the fork down!” Bonus: It throws a wrench in your stomach’s clearing process, so you’re feeling stuffed for longer.

Now, Phentermine is a different beast. Think of it as a turbo booster for your central nervous system. It amps up the release of feel-good players like dopamine and norepinephrine. These bad boys don’t just make you feel good; they slam the brakes on hunger. Plus, it cranks up your body’s calorie-torching system, so you’re burning calories while chilling.


Semaglutide for weight loss comes in a wide range of strengths, from 0.25 mg (weeks 1 to 4), 0.5 mg (weeks 5 to 8), 1 mg (weeks 9 to 12), and 1.7 mg (weeks 13 to 16). The maintenance dose is 2.4 mg from week 17 onwards. It is usually administered subcutaneously once a week. 

Phentermine, meanwhile, is a twice-a-day kind of deal. The dosage isn’t one-size-fits-all: it ranges from 15 to 37.5 mg daily, but only if you’re 17 or older.

So, whether it’s Semaglutide or Phentermine, dosage isn’t a guessing game. Always follow your healthcare provider’s advice.

Duration of the treatment

Semaglutide’s a long-haul player in managing type 2 diabetes; you’ll likely be on it for the foreseeable future. For battling obesity, it’s a shorter gig, usually clocking in at 16-20 weeks. Some folks might need to stick with it for up to a year.

Phentermine’s more of a quick fix, maxing out at about 12 weeks. To be clear, it’s not your go-to for the long run.

Effectiveness in Weigh Loss

Semaglutide’s track record in clinical trials is stellar. One shot saw folks shedding a whopping 15% of their body weight over 68 weeks. Another dialed it back a bit, but still impressive, showing a 12% weight loss over 52 weeks.

Phentermine needs to catch up, too; it has its applause-worthy results. In one study, users kissed goodbye to 10% of their body weight in just 12 weeks. Another found a 7% weight drop over 24 weeks.

Here’s the kicker: These meds work differently for everyone. Weight loss can be a mixed bag, varying from person to person. So, don’t slack off on the healthy eating and exercise while you’re poppin’ either of these pills if you want to knock those pounds out of the park.

Possible Side Effects

While Semaglutide is mostly a smooth ride, it’s not all rainbows and butterflies. You might deal with common nuisances like nausea, throwing up, diarrhea, and the big C—constipation. You could also run into headaches, fatigue, and feeling woozy. And although it’s rare, serious stuff like pancreatitis, thyroid issues, and kidney problems could rear their ugly heads.

Phentermine’s got its quirks, too. Most commonly, you’re looking at a dry mouth, constipation, and restless nights. It can also throw you for a loop with symptoms like anxiety and irritability. While rare, heavy hitters like heart issues, strokes, and seizures are also in the mix.

So, just a heads-up—no med’s a miracle worker without drawbacks.

Cost Comparison

The cost of Semaglutide is all over the map, influenced by factors like your treatment plan, insurance, and where you’re shopping. Sans insurance, you’re peering at a price tag between $970 and $2,120 a month. Plus, brands like Ozempic, Wegovy, and Rybelsus each have their own pricing game.

Phentermine is easier on the wallet and remains America’s go-to appetite buster. A generic Phentermine 37.5 mg tablet pack typically hovers around $32.35; capsules are just a tad more at around $36. But watch out for Qsymia—this high-roller of the Phentermine world can set you back anywhere from $194 to $240 monthly, depending on the dosage.

So yeah, when it comes to your pocketbook, these meds are in different leagues entirely.

Drug interactions

Semaglutide doesn’t play well in the sandbox with all your other meds. It can butt heads with insulin, other diabetes treatments, and even mess with blood thinners. It could also get tangled up with meds impacting serotonin levels, like tricyclic antidepressants and MAOIs.

Phentermine’s got its own “doesn’t play well with others” list, too. Antidepressants, blood pressure meds, and heart meds are on the list. It can also tango poorly with various antidepressants like MAOIs, SSRIs, and SNRIs, not to mention Fintepla, other weight loss drugs, and even your weekend wine.

Don’t pop either of these pills without a sit-down with a healthcare provider or pharmacist to dodge any nasty drug interactions.

Related article: How To Flush Phentermine Out Of Your System

Who Should Avoid These Medications?

If you’ve battled with pancreatitis or certain types of thyroid cancer, give Semaglutide a hard pass. It hasn’t even been tested on folks with pancreatitis. Also, if thyroid issues or Multiple Endocrine Neoplasia type 2 runs in the family, proceed cautiously.

Phentermine’s off the table if you’ve dealt with heart problems, soaring blood pressure, a hyperactive thyroid, glaucoma, or past substance abuse issues.

When weighing the pros and cons of taking either Semaglutide or Phentermine, here’s what else you should mull over:

Age: Keep the Semaglutide away from anyone under 18, and Phentermine’s off-limits for the under-12 crowd.

Pregnancy and breast-feeding: Neither of these drugs gets the green light during pregnancy or breastfeeding.

Other medications: Both can clash with other drugs, so give your doctor the full rundown on what you’re taking.

Frequently Asked Questions

Can you take Phentermine and semaglutide together?

No, mixing Phentermine and semaglutide is a no-go. Phentermine is a stimulant that, when combined with semaglutide, ups the ante for severe side effects like heart attack and stroke. Not to mention, taking these meds together could also make your blood sugar plummet.

Is ozempic better than phentermine?

Ozempic tends to outperform Phentermine in weight loss effectiveness and long-term results, plus it's generally safer. That said, Phentermine is easier on the wallet. The ideal pick depends on your unique situation and budget.

Is wegovy better than Phentermine?

Wegovy usually beats Phentermine in the weight loss game, offering more effective results and fewer side effects. If you aim to lose weight and keep it off, Wegovy is the safer bet.

Can you take one pic with Phentermine?

Mixing Ozempic and Phentermine is possible, but it's not advised. Though the two have no known lousy reaction, they haven't been studied together. Plus, doubling weight loss meds could increase your odds of side effects.

Does wegovy have Phentermine in it?

Nope, Wegovy doesn't contain Phentermine. Its active ingredient is semaglutide, a GLP-1 receptor agonist that mimics a natural hormone to help control hunger. Phentermine, by contrast, is a stimulant that curbs your appetite.

Can you take Adipex with Ozempic?

Technically, mixing Adipex and Ozempic is doable, but it's a no-go in medical advice. They have yet to be studied as a pair, so their safety and effectiveness together is a question mark. Plus, doubling down on weight loss meds could increase your risk for side effects.

Can you take ozempic and qsymia together?

No, mixing Ozempic and Qsymia isn't a good idea. Ozempic is a GLP-1 receptor agonist, and Qsymia combines Phentermine with topiramate. Both can increase your risk for not-so-fun side effects like low blood sugar, heart flutters, and anxiety.

Can I take berberine with Phentermine?

Taking berberine with Phentermine? Not the best move. While berberine is a natural weight loss supplement, it can clash with Phentermine, upping your chances of side effects like low blood sugar, heart jitters, and anxiety.

Can you take contrave and semaglutide together?

Pairing up Contrave and semaglutide? Bad idea. Contrave blends naltrexone with bupropion, while semaglutide is a GLP-1 receptor agonist. Mixing them can spike your risk for nasty side effects like low blood sugar, heart flutters, and anxiety.

Can you take metformin and Phentermine together?

Combining metformin and Phentermine? Think twice. Metformin's a diabetes med, and Phentermine suppresses appetite—both can lower blood sugar. Taking them together could put you on the fast track to hypoglycemia or dangerously low blood sugar.

Does Phentermine make you constipated?

Phentermine can throw a wrench in your digestive flow, making you constipated. It's a stimulant that slows down food's journey through your gut. Watch out for other side effects, like dry mouth, sleep issues, anxiety, and a racing heart.

Final Thoughts

Both semaglutide and Phentermine get the job done for shedding pounds, but they have pros and cons. Semaglutide is usually a year-long commitment, while Phentermine’s more of a quick fix, maxing out around 12 weeks. 

Your unique situation and objectives will steer you toward the right choice. So, chat with your doctor to determine the best fit for you.

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