How These Medications Work, In Plain Terms.
A deeper look at GLP-1 medications — how they work in the body, what to expect during treatment, who should not take them, and the different ways they can be taken.
Works on two receptors at once. Most often given as a weekly injection, and also made in daily oral and sublingual forms.
Works on the GLP-1 receptor. Most often given as a weekly injection, and also made as a daily pill or sublingual.
Three Things Worth Knowing First
These are the points that most often surprise people in the first couple of months.
There Is No One Right Dose
Some people respond at low doses. Others titrate up over several months before they see much. Not seeing a change early is common, and it is not a sign the medication won’t work for you — your provider adjusts based on how you respond, not toward a target number.
Restarting Feels Different
If you have taken a GLP-1 before, the response may be a little slower when you restart — how much depends on the dose you reached and how long you were off it. Your provider can help you decide whether to titrate up more quickly.
It Is A Tool, Not The Whole Plan
The medication works best alongside changes to how you eat and move. Its biggest contribution is on the diet side — it makes those changes easier to sustain rather than making them unnecessary.
What The Medication Is Doing In Your Body
Semaglutide and tirzepatide both increase insulin production and lower glucagon secretion, and both act on the parts of the brain that regulate appetite and food intake. A small change to the molecule lets it last weeks in the body rather than the minutes the natural version lasts.
- Slows Stomach EmptyingFood leaves the stomach more slowly, so smaller meals feel filling and satisfying.
- Slows Intestinal MotilityYou stay full for longer after a meal, not just during it.
- Lowers Blood SugarPartly by reducing how much sugar the liver produces in the first place.
- Stimulates Insulin ReleaseThe pancreas releases insulin in response to what you eat.
- Reduces AppetiteBy stimulating the satiety signal in the hypothalamus — the “I’ve had enough” response.
- Tirzepatide Adds GIPGIP has been shown to improve pancreatic beta-cell function and insulin secretion after diet-induced weight loss, and it helps increase energy expenditure.
Which One Is Right For Me?
Three factors usually decide it. If you are still unsure, your provider can help you choose — and you can switch between the two later with their guidance.
Effectiveness
Head to head over 72 weeks, tirzepatide produced more weight loss than semaglutide — about 20% of body weight versus about 14%. Those are trial averages, though, and plenty of patients do very well on semaglutide.
Side Effects
The side effects are very similar between the two. Some patients experience more of them on semaglutide, particularly gastrointestinal side effects.
Cost
Entry-level plans for the two now start within a few dollars of each other. Where a difference shows up is at higher doses, and even then it varies a lot by pharmacy. Worth comparing the actual plans side by side rather than assuming one is cheaper.
Not Every GLP-1 Is A Weekly Shot
Most people start on a weekly injection, which is why it is the form described most often. It is not the only one — the same medications also come as pills, as tablets that dissolve in your mouth, and as liquids you hold under your tongue, and there is a GLP-1 that is injected daily.
Compounded Oral & Sublingual
Taken DailyThe same two medications — semaglutide and tirzepatide — made as a liquid you hold under your tongue, or as a tablet that dissolves in your mouth. Taken daily rather than weekly.
Some people prefer this simply because it is not a needle. Plan sizes and doses work differently from the injectable tiers, so it is worth looking at the plans before deciding.
Wegovy® Pills
Oral SemaglutideThe brand-name pill version of semaglutide, from 1.5mg up to 25mg. Taken once a day.
The timing matters with this one. Take it first thing in the morning on an empty stomach with no more than 4 ounces of plain water, swallow it whole, then wait at least 30 minutes before food, any other drink, or any other oral medication.
Foundayo™
Oral OrforglipronThe newest option, approved in April 2026. Unlike every other GLP-1, it is a small molecule rather than a peptide — which is why it is the only one you can take any time of day, with no food or water rules at all.
Once daily, six strengths from 0.8mg to 17.2mg. In its main trial, people on the highest dose lost about 12 percent of their body weight on average.
Liraglutide
Daily InjectionStill an injection, but given once a day rather than once a week. It is an older GLP-1 than semaglutide and tirzepatide.
About Compounded Medications
While we only send prescriptions to vetted and accredited compounding pharmacies, the medications they provide are not FDA approved or regulated. The availability of any particular compounded medication also can’t be guaranteed under the regulations governing it.
How Much Weight Will I Lose?
Across trials, average weight loss lands around 14 percent on semaglutide and around 20 percent on tirzepatide. Yours can be more or less depending on your starting point, the dose you reach, how long you stay on treatment, and the changes you make alongside it.
Who Should Not Take It & What To Watch For
Your provider reviews all of this with you before prescribing, but it is worth reading first. Most side effects are the ordinary ones below — the rest of this section is what to do in the rare cases that need more than waiting it out.
Do Not Take This Medication If
- You or a family member has a history of medullary thyroid cancer, or of multiple endocrine neoplasia type 2 — there is a possible increased risk of medullary thyroid cancer in this group.
- You have severe gastrointestinal disease.
- You are pregnant or breastfeeding.
Tirzepatide only: if you use oral contraceptives, switch to a non-oral method or add a barrier method for 4 weeks after starting tirzepatide, and for 4 weeks after each dose increase. This is on tirzepatide’s label specifically — semaglutide does not carry the same instruction.
Common Side Effects
All medications can cause side effects. The most common with this class are nausea, diarrhea, vomiting, constipation, abdominal pain, indigestion, injection site reactions, fatigue, belching, hair loss and acid reflux. It can also slow stomach emptying.
If you take other medications that lower blood glucose, this class can increase the risk of low blood sugar. Tell your provider about everything you are taking.
Call 911 Or Go To An Emergency Room
Stop the medication and get emergency help for signs of a serious allergic reaction:
- Swelling of your face, lips, tongue or throat
- Trouble breathing or swallowing
- Severe rash or itching, a very fast heartbeat, or feeling faint or dizzy
Stop The Medication & Get Seen Today
These are rare, but they are the ones not to wait out. Stop the medication and get evaluated in person — urgent care, your primary care provider, or an emergency room:
- Severe stomach pain that does not go away, sometimes spreading through to your back, with or without vomiting — this can be pancreatitis
- Pain in your upper stomach, yellowing of your skin or eyes, fever, or clay-colored stools — these can be gallbladder problems
- Vomiting or diarrhea you cannot get ahead of, or not being able to keep fluids down — dehydration this severe can injure your kidneys
- Severe stomach pain with no bowel movement and a swollen belly — this can be a bowel obstruction
Since we are a remote practice, we can’t provide emergency or same-day in-person care, as your provider won’t be available every day. Message us as well so it is on your record, but get seen first.
Tell Your Provider Promptly
Not emergencies, but they should not wait until your next scheduled visit either. Message your provider if you notice:
- A lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath
- Any change in your vision
- Signs of low blood sugar — shakiness, sweating, confusion, blurred vision, or a fast heartbeat. This is more likely if you also take insulin or another medication that lowers blood glucose
- Changes in your mood that are new, getting worse, or worrying you
The Two Questions Everyone Asks
How Long Do You Stay On It?
There is no set length. How long you stay on treatment is decided in conversation with your provider, based on how you are doing and what you want from it.
One practical note: tell your surgical and anesthesia team you are taking it well before any procedure, and give them the medication name, your dose, and the date of your last dose. They may ask you to stop it for a period beforehand — that decision belongs to the team performing your procedure.
What If I Miss A Dose?
The rule is different for the two medications, so check the one you are on.
Tirzepatide: take the missed dose as soon as you can, within 4 days (96 hours) of when it was due. Past 4 days, skip it and take your next dose on the regular day. If you want to move your weekly day, you can — as long as there are at least 3 days (72 hours) between the two doses.
Semaglutide: if your next scheduled dose is more than 2 days (48 hours) away, take the missed one as soon as you remember. If it is less than 2 days away, skip it and take your next dose on the regular day. If it has been 2 weeks or more since your last dose, message your provider before restarting rather than picking up where you left off.
For both: never take two doses at once to make up for a missed one. It raises your risk of side effects without helping.
Two Guides Worth Bookmarking
Self-Injection Guide
Your key tool for the injection itself — subcutaneous, intramuscular, and how to read and verify your vial. A link is included in every order confirmation email. Worth bookmarking or printing.
Open The GuidePatient Guide
The full handbook — how care works end to end, refills, follow-ups, payments, orders, shipping, storage and support. The reference for general procedures and information.
Open The GuideApps Our Providers Like
Optional, and none of them are ours — just tools patients have told us made a difference.
Happy Scale
Smooths out daily scale weights into a trend and predicts when you will hit a goal.
MeThreeSixty
A three-dimensional body scan over time, for when a single number doesn’t tell the story.
Shotsy
Log weekly shots, track side effects, and view estimated concentration levels.
MyFitnessPal
All-in-one food, calorie and exercise tracking.
Questions A Page Can’t Answer
Which medication suits you, what dose to start at, and how quickly to move up are all decisions your provider makes with you.
Book A ConsultThis page is general information about a class of medication, not medical advice for your situation. Individual results vary. Your provider reviews your history, your current medications and your goals before prescribing anything.