Semaglutide

• Week 1-2: Users often notice less appetite by week 2; nausea may start
• Week 2-4: Stay at 0.25 mg (10 units) so your stomach adjusts
• Week 4-8: Up to 0.5 mg (20 units); stomach upset most likely now
• Week 8-12: Up to 1 mg (40 units); weight loss builds slowly
• Side effects: Mostly mild to moderate stomach upset; stop for severe belly pain

More on each stage

Week 1-2

Each shot peaks in your blood 1 to 3 days after you inject it. Community users often notice less appetite within the first 1-2 weeks. Mild nausea or fullness can start now.

Week 2-4

Levels keep building with each weekly shot and level off after about 4-5 weeks on the same dose. You stay at 0.25 mg (10 units) for all 4 weeks: this step lets your stomach adjust.

Week 4-8

From week 5 the label moves to 0.5 mg (20 units). Stomach side effects are most common while the dose is going up. If a step feels rough, stay on it 4 more weeks before moving up.

Week 8-12

From week 9 the label moves to 1 mg (40 units). Weight loss builds slowly: in the STEP 4 trial, people had lost 10.6% of their weight on average by week 20, after the full step-up to 2.4 mg. In STEP 1 the average loss reached 14.9% at 68 weeks, compared with 2.4% on a dummy shot. Results depend on how much you still eat.

Side effects

Most often nausea, diarrhea, vomiting, constipation, and belly pain, mostly mild to moderate and fading with time. Stop and get help for severe belly pain that will not go away, signs of an allergic reaction, or yellow skin or eyes.

Based on what people report in the community sources below. Results vary, and many responses are anecdotal.

• Weight loss

  FDA-labeled

  In the STEP 1 trial of 1,961 adults without diabetes, 2.4 mg once a week plus diet and exercise cut body weight by 14.9% on average over 68 weeks, compared with 2.4% on placebo (a dummy shot). The FDA label reports that 47.9% of people on semaglutide lost 15% or more, compared with 4.8% on placebo. These results came at 2.4 mg, the top of the step-up plan.13

• Less hunger, less eating

  FDA-labeled

  The FDA label says semaglutide lowers how many calories people eat, most likely by acting on appetite. It also slows how fast the stomach empties, so you feel full longer.1

• Appetite drops early

  Community report

  Community users often report less appetite within the first 1-2 weeks, and many stay on 1-1.7 mg long term for appetite control rather than going higher. These are self-reports.14

• Fewer heart attacks and strokes

  FDA-labeled

  In the SELECT trial of 17,604 adults with heart disease and overweight but no diabetes, 2.4 mg a week cut heart attacks, strokes, and heart deaths by 20% (6.5% vs 8.0% had one over about 3 years).17

• Better blood sugar in type 2 diabetes

  FDA-labeled

  Ozempic (semaglutide 0.5 mg to 2 mg a week) is FDA-approved to lower blood sugar in adults with type 2 diabetes. It raises insulin and lowers glucagon only when blood sugar is high.21

• Kidney protection in type 2 diabetes

  FDA-labeled

  In the FLOW trial of 3,533 adults with type 2 diabetes and kidney disease, 1 mg a week cut the risk of serious kidney events or death from kidney or heart causes by 24% over a median of 3.4 years.28

• Less liver inflammation

  FDA-labeled

  In adults with fatty-liver inflammation (MASH) and liver scarring, 2.4 mg a week cleared the inflammation in 63% of people at 72 weeks, compared with 34% on placebo (FDA label). Scarring improved in 37% vs 22%.19

What it has been studied for

• Long-term weight loss in adults with obesity, or overweight plus a weight-related condition, and in children 12 and older with obesity (Wegovy)13FDA-labeled
• Lowering the risk of heart attack, stroke, and heart death in adults with heart disease and overweight or obesity (Wegovy)17FDA-labeled
• Blood-sugar control in adults with type 2 diabetes, and lowering heart risk in those with heart disease (Ozempic)2FDA-labeled
• Slowing kidney decline in adults with type 2 diabetes and chronic kidney disease (Ozempic)28FDA-labeled
• Fatty-liver inflammation (MASH) with moderate to advanced scarring, without cirrhosis (Wegovy; accelerated approval pending a confirming trial)19FDA-labeled
• Keeping weight off: continuing vs stopping after 20 weeks of treatment (STEP 4), and weight regain after stopping (STEP 1 extension)54Clinical trial
• Weight loss in adults with type 2 diabetes, comparing 1 mg and 2.4 mg (STEP 2)6Clinical trial

Semaglutide is a lab-made, long-lasting copy of a gut hormone (GLP-1) that your body releases after meals. It shares 94% of its building blocks with the human version. A fatty tail makes it stick to a protein in your blood (albumin), which protects it from being broken down. That is why one shot lasts a week. It works like a key that switches on the hormone's locks in the brain's appetite centres, the pancreas, and the stomach. You feel full sooner, eat less, and your blood sugar stays steadier.

Peak

1 to 3 days after an under-the-skin shot. About 89% of a shot reaches the blood, and the belly, thigh, and upper arm absorb the same. Levels level off after 4-5 weeks of weekly shots at the same dose.

Half-life

About 1 week (FDA label), which is why it is a once-a-week shot. It has not been measured for research vials.

Cleared

About 5 to 7 weeks after the last shot (FDA labels: about 5 weeks for Ozempic doses, 5 to 7 weeks after Wegovy 2.4 mg or 7.2 mg). Because it lasts so long, stop at least 2 months before a planned pregnancy, and an overdose can need a long period of medical watching.

Half-life is how long it takes the body to remove half of a dose.1211

Once a week. Same day each week, any time of day, with or without food. Every week, no days off. 0.25 mg is the starting step, not the long-term dose: the label raises the dose every 4 weeks, and only if you feel OK. Units are for a 5 mg vial mixed with 2 mL water (2.5 mg per mL).

Step-up plan

When	Dose	Units
Weeks 1-4 Start here Store dose	0.25 mg	10 units
Weeks 5-8	0.5 mg	20 units
Weeks 9-12	1 mg	40 units
Weeks 13-16	1.7 mg	68 units
Week 17 on (label maintenance: 1.7 mg or 2.4 mg)	2.4 mg	96 units

• Lower end · labeled starting month

  0.25 mg once weekly for 4 weeks

  The Wegovy injection label starts every approved use here, for 4 weeks, before any increase.1

• Most common · labeled escalation

  Step up every 4 weeks after 0.25 mg

  After the first 4 weeks the label raises the weekly injection about every 4 weeks. If a step is not tolerated, the label says to wait before raising it.1

• Higher end · labeled injection maintenance

  2.4 mg once weekly

  2.4 mg once weekly is the Wegovy injection strength listed as a maintenance product. The label reaches it only after the earlier steps.1↗

• Standard step-up

  Same steps as the label: 0.25 mg, 0.5 mg, 1 mg, and 1.7 mg for 4 weeks each, then 2.4 mg once a week, ongoing.14

• Slower step-up

  6-8 weeks on each step instead of 4, to cut stomach side effects.14

• Low-dose maintenance

  0.5-1 mg once a week, ongoing. Many users report staying at 1-1.7 mg long-term for appetite control rather than going to 2.4 mg.14

• Microdose or split dose

  0.125-0.25 mg twice a week, ongoing (5-10 units with this mix).14

Research protocols

• FDA label, Wegovy injection (all approved uses)

  0.25 mg once a week for weeks 1-4, 0.5 mg for weeks 5-8, 1 mg for weeks 9-12, 1.7 mg for weeks 13-16, then 1.7 mg or 2.4 mg (preferred) once a week from week 17. If a step is not tolerated, wait 4 more weeks before moving up. The store protocol (0.25 mg weekly) is the label's first step.1

• FDA label, Wegovy HD (adults needing more weight loss)

  After at least 4 weeks on 2.4 mg, the dose may go up to a maximum of 7.2 mg once a week. In a 72-week trial in adults with obesity, 7.2 mg cut weight by 18.8% vs 15.5% on 2.4 mg, but skin-sensation side effects rose to 22%. 7.2 mg is 288 units with this vial mix, so it is not practical from a 5 mg vial.1

• FDA label, Ozempic (type 2 diabetes)

  0.25 mg once a week for 4 weeks, then 0.5 mg. If more blood-sugar control is needed, 1 mg after at least 4 weeks, then 2 mg after at least 4 more weeks.2

• STEP 1 weight-loss trial (1,961 adults without diabetes)

  Stepped up over 16 weeks to 2.4 mg once a week, then 2.4 mg to week 68, with a lower-calorie diet and more activity.31

• STEP 4 keep-going-or-stop trial (902 adults)

  Everyone stepped up to 2.4 mg over 16 weeks and stayed 4 more weeks (20-week run-in, 10.6% average loss). Then 2.4 mg weekly or a dummy shot for 48 weeks.5

• STEP 2 trial (1,210 adults with type 2 diabetes)

  1 mg or 2.4 mg once a week, or placebo, for 68 weeks.6

• FLOW kidney trial (adults with type 2 diabetes and kidney disease)

  1 mg once a week; median follow-up 3.4 years.8

• SELECT heart trial and ESSENCE fatty-liver trial

  2.4 mg once a week after a 16-week step-up (people could stay on a lower dose if needed), for about 3 years in SELECT; 2.4 mg once a week with results at 72 weeks in ESSENCE.719

This schedule is for the FDA-labeled Wegovy injection, prescribed and dispensed as that product. A research vial priced here is not a Wegovy pen, and the amount in the vial may not match the pen. Stomach side effects are why the label starts at 0.25 mg. Do not copy a high weekly dose on week one.

Dosing guidance built from the cited research and community reports. It is not a prescription.

On

Ongoing (step up every 4 weeks)

Break

No routine break

Why the break helps

No study shows that a break makes semaglutide work better, and stopping usually brings weight back. One year after people stopped 2.4 mg in the STEP 1 trial, they had regained about two-thirds of the weight they lost, and most of their heart-and-metabolism improvements faded back toward where they started. In the STEP 4 trial, people switched to a dummy shot after 20 weeks gained 6.9% over the next 48 weeks, while those who stayed on lost another 7.9%. Community users report the same regain. Good reasons to pause: planning a pregnancy (stop at least 2 months before), a side effect from the serious list, or surgery (tell your doctor). If you miss 2 or more weekly doses in a row, restart at a lower step, because the stomach side effects can come back.

Common

• Nausea (44% vs 16% on placebo at 2.4 mg), diarrhea (30% vs 16%), vomiting (24% vs 6%), or constipation (24% vs 11%). Most common while the dose is going up, mostly mild to moderate, and usually fades.

  What to do Eat slowly, eat smaller portions, stop when you feel full, and pick bland, low-fat food. Sip fluids through the day. Do not step up while symptoms last; stay on your current dose 4 more weeks, or go back one step. If vomiting or diarrhea will not stop, get medical help (see dehydration below).

• Belly pain (20% vs 10%), bloating, burping, heartburn, or gas

  What to do Smaller, lower-fat meals help. Belly pain that is severe or will not go away is a warning sign: see the serious list.

• Headache (14% vs 10%), tiredness (11% vs 5%), or dizziness (8% vs 4%)

  What to do Drink enough fluids and stand up slowly. If you faint, stop and see a doctor.

• Hair thinning (3% vs 1%), linked to weight loss and more common in women

  What to do Usually tied to losing weight. Tell a doctor if it is heavy or does not settle.

• Odd skin feelings such as tingling, burning, or sensitive skin (2-6% at 2.4 mg in trials, 22% at 7.2 mg)

  What to do Tell a doctor. In trials, lowering the dose or pausing helped it settle faster.

• Redness or itching where you injected (about 1.4% vs 1%)

  What to do Rotate spots and use a fresh syringe every time. If redness spreads or gets hot and painful, treat it as an infection (see below).

Stop and get help

• Pancreatitis: severe belly pain that will not go away, sometimes spreading to the back, with or without vomiting

  What to do Stop semaglutide and get medical care right away.

• Gallbladder problems or gallstones: pain in the upper belly, fever, yellow skin or eyes, or pale, clay-colored stools

  What to do Stop and see a doctor promptly. Some gallbladder problems need surgery.

• Dehydration from ongoing vomiting or diarrhea, which can damage the kidneys

  What to do Drink fluids. If you cannot keep fluids down or it does not stop, get medical help the same day.

• Serious allergic reaction: swelling of the face, lips, tongue, or throat, trouble breathing or swallowing, severe rash, very fast heartbeat, or fainting

  What to do Stop semaglutide and call 911 (or your local emergency number) right away.

• Severe nausea and vomiting after drawing a dose (possible overdose from a unit or mL mix-up)

  What to do Call the Poison Help line at 1-800-222-1222 or go to the emergency room. Because semaglutide lasts about a week, you may need to be watched for a long time.

• Severe constipation with belly swelling, no gas or stool, and vomiting (possible bowel blockage)

  What to do Stop and get emergency care.

• A lump or swelling in the neck, hoarseness that lasts, trouble swallowing, or shortness of breath

  What to do Stop and see a doctor. Semaglutide caused thyroid tumors in rodents; whether it does in people is not known.

• Low blood sugar if you take insulin or a sulfonylurea: shakiness, sweating, confusion, fast heartbeat, or blurred vision

  What to do Treat it with fast sugar right away and call your doctor; your diabetes medicine dose may need lowering.

• Heart racing or pounding at rest for several minutes, or vision changes if you have diabetes

  What to do Stop and tell a doctor promptly.

• Infection at the injection site: redness that spreads, heat, pus, red streaks, or fever

  What to do Stop injecting and see a doctor the same day.

Do not use if

• You or anyone in your family has had medullary thyroid cancer (MTC), or you have MEN 2 (a genetic gland-tumor syndrome). The label forbids it.
• You have had a serious allergic reaction to semaglutide.
• You are pregnant or plan to be within 2 months: it may harm an unborn baby, and it stays in your body for weeks.
• You are breastfeeding: there is no data on whether injected semaglutide passes into breast milk. Talk to your doctor first.
• You already take another GLP-1 drug, such as Ozempic, Wegovy, tirzepatide, or retatrutide.
• You have severe gastroparesis (a very slow-emptying stomach).
• You have type 1 diabetes or use insulin, unless your doctor manages it: this has not been studied and low blood sugar is a risk.
• You have had pancreatitis, kidney problems, or diabetic eye disease, unless a doctor agrees and checks on you.
• You have surgery or a procedure with anesthesia or deep sedation coming up, unless you tell the team first: food left in the stomach can be breathed into the lungs.
• You are under 18: the brand drug is approved from age 12 only under a doctor's care.

Sources1112

Storage

Keep it

Keep the mixed vial in the fridge (2-8 °C, 36-46 °F), upright and away from light. Do not freeze it or keep it right next to the fridge's cooling element, and do not use it if it has frozen. Never leave it in a hot car.

How long

Use within 90 days of mixing. A mixed vial kept in the fridge holds its strength for 60-90 days, then slowly starts to lose potency. Wipe the rubber top with an alcohol swab before every draw.

Drawing your dose

Syringe: a 0.5 mL (50-unit) U-100 insulin syringe. Doses above 50 units (up to 96 here) need a 1 mL (100-unit) syringe.

1. With this mix, each 1-unit line on a U-100 insulin syringe holds 0.025 mg (25 mcg). Draw 10 units for 0.25 mg, 20 units for 0.5 mg, 40 units for 1 mg, 68 units for 1.7 mg, or 96 units for 2.4 mg.
2. Units are not millilitres. The FDA has reports of people told to draw 5 units who drew 50 instead, and some overdoses were 5 to 20 times the intended dose. Read the unit lines, not the mL lines, and double-check before you inject.
3. One 5 mg vial on the label's step-up plan covers about 10 weeks: four 0.25 mg shots (1 mg), four 0.5 mg shots (2 mg), then two 1 mg shots (2 mg). At 2.4 mg it holds only 2 doses.
4. Check the liquid before each dose. It should be clear and colorless with no specks. Do not use it if it looks cloudy or colored.
5. Wipe the top before every draw. Hold the syringe at eye level, flick out air bubbles, and push the plunger back to the exact line.
6. Missed a dose? If your next dose is more than 2 days away, take it now. If it is less than 2 days away, skip it and inject on your usual day. You can move your shot day as long as your last shot was at least 2 days earlier.
7. Use a new sterile syringe every time and never share one, even with a new needle.

• Tesamorelin

  Part of the weight semaglutide takes off is lean mass, not just fat. Tesamorelin works a different way, by raising your own growth hormone: it does not change body weight, but in its FDA trials it raised lean body mass by about 1.2-1.3 kg over 26 weeks. That makes it a possible partner for keeping muscle while losing fat. Tesamorelin can raise blood sugar, so get your blood sugar checked if you combine them.113

Interactions

• Other GLP-1 drugs: Ozempic, Wegovy, other semaglutide, tirzepatide, retatrutide

  They hit the same receptor, so side effects stack up. The FDA label says not to combine semaglutide with any other GLP-1 drug.

  What to do Use only one. If you switch, ask a doctor how to change over, because semaglutide stays in your body for weeks.

• Insulin or sulfonylureas (such as glipizide, glyburide, glimepiride)

  Higher risk of low blood sugar, including severe lows.

  What to do Talk to your doctor before you start; your dose may need lowering. Check your blood sugar before and during treatment.

• Pills that need careful dosing, such as warfarin, thyroid hormone (levothyroxine), or seizure medicines

  Semaglutide slows stomach emptying, which can change how pills are absorbed. With the semaglutide tablet, levothyroxine levels rose 33%. In studies with 1 mg shots, metformin, warfarin, digoxin, atorvastatin, and birth-control pills needed no dose change.

  What to do Tell your doctor or pharmacist; they may want extra blood tests.

• Blood-pressure medicines

  Low blood pressure and fainting happened more often on semaglutide, especially in people on blood-pressure pills and when vomiting or diarrhea caused fluid loss.

  What to do Stand up slowly, drink enough fluids, and tell your doctor if you feel dizzy or faint.

• Anesthesia or deep sedation for surgery, endoscopy, or other procedures

  Food can stay in the stomach despite fasting and be breathed into the lungs.

  What to do Tell every doctor and dentist you take semaglutide before any planned procedure.

Sources

1. 1FDA prescribing information, Wegovy (semaglutide) injection and tablets, revised 6/2026Drug label
2. 2FDA prescribing information, Ozempic (semaglutide) injection, revised 1/2025Drug label
3. 3Wilding et al., N Engl J Med 2021 (STEP 1: 2.4 mg weekly, 1,961 adults, 68 weeks)Clinical trial
4. 4Wilding et al., Diabetes Obes Metab 2022 (STEP 1 extension: weight regain after stopping)Clinical trial
5. 5Rubino et al., JAMA 2021 (STEP 4: continuing vs stopping after 20 weeks)Clinical trial
6. 6Davies et al., Lancet 2021 (STEP 2: 1 mg vs 2.4 mg in type 2 diabetes, 68 weeks)Clinical trial
7. 7Lincoff et al., N Engl J Med 2023 (SELECT: heart outcomes, 17,604 adults without diabetes)Clinical trial
8. 8Perkovic et al., N Engl J Med 2024 (FLOW: kidney outcomes, 1 mg weekly)Clinical trial
9. 9Sanyal et al., N Engl J Med 2025 (ESSENCE: fatty-liver inflammation, 2.4 mg weekly, 72 weeks)Clinical trial
10. 10Gorgojo-Martínez et al., J Clin Med 2022 (expert consensus: managing stomach side effects of GLP-1 drugs)Review
11. 11FDA alert: dosing errors with compounded semaglutide in multi-dose vials (July 2024)Reference
12. 12FDA: Concerns with unapproved GLP-1 drugs used for weight loss (updated 10/2026)Reference
13. 13FDA prescribing information, EGRIFTA WR (tesamorelin), revised 3/2025 (lean body mass results)Drug label
14. 14Peptide Protocol Wiki: Semaglutide community protocols (500 reports)Community

Where people discuss it

• FDA Wegovy prescribing information
• r/Semaglutide (subreddit)

Some peptides, like semaglutide (Ozempic and Wegovy), are FDA-approved medicines. Most of the peptides people research are not. That label sounds like the FDA tested something and turned it down. Usually it means something else: nobody has paid for the studies the FDA needs to see. Here is why.

The FDA doesn’t test drugs. Companies do.

The FDA does not run its own drug tests. A company that wants to sell a new medicine has to test it first, and pay for it. It studies the drug in animals, then in people: first 20 to 100 volunteers, then a few hundred, then up to 3,000. Then it sends all the results to the FDA. FDA scientists review them and decide whether the benefits outweigh the risks.

So approval always starts with a company asking for it. If no company applies, the FDA has nothing to review, however promising the research looks.

Those studies cost about a billion dollars

A study in the medical journal JAMA estimated that bringing one new drug to market costs a typical company about $1.1 billion. That figure includes the money spent on drug ideas that failed along the way, because many drugs that start human testing never make it.

A patent is how a company earns that money back

A patent is a right the government gives an inventor. For up to 20 years from the day the inventor applies, nobody else may make or sell the invention without permission.

For a drug company, that right is what makes the billion-dollar bet worth it. While the patent lasts, the company is the only seller, so it can charge enough to pay back the studies and the failures. When the patent runs out, other companies can sell cheap copies, called generics, and the price drops.

The FDA adds a shorter shield of its own. For 5 years after a brand-new drug is approved, no copycat version can apply for approval. That helps, but it is much shorter than a patent can last.

Why most peptides can’t be patented

To get a patent, an invention has to be new, and it has to be something people made, not something found in nature. Most popular peptides fail one test or both.

They come from nature. Many are copies or small pieces of molecules your body already makes. KPV is a 3-building-block piece of the hormone that tans your skin. BPC-157 is copied from a protein in stomach juice. In 2013 the US Supreme Court ruled that something that exists in nature, like a human gene, cannot be patented just because someone found it and pulled it out.

They aren’t new anymore. Many were first described in research papers decades ago. Scientists were already testing KPV in the 1980s. Once something has been published, it no longer counts as new, so nobody can patent it now, and any patents from back then have long since run out.

Without a patent, a company that paid for the studies would soon face rivals selling the same peptide without having paid for any research. Few companies will spend a billion dollars on a product anyone can copy. So nobody goes first, and the large human studies never happen.

The workaround: change the molecule

Drug companies do make peptide medicines, but they change the peptide first. A changed molecule is a new invention, so it can be patented. Semaglutide is a lab-made version of GLP-1, a gut hormone your body releases after meals, changed so one shot lasts a week. Tesamorelin (Egrifta) is the body’s own growth-hormone signal with a small fatty chain added. Both went through the full studies, and both are FDA-approved.

The natural versions, and the many peptides nobody has changed and patented, stay where they are: studied in labs and animals, used by the biohacking community, and never put through large human trials.

What this means for you

When a peptide is “not FDA-approved,” it usually means no company has paid for the large human studies. It does not mean the FDA tested it and found it harmful.

It also does not mean it is proven safe or proven to work. Without those studies, nobody knows the best dose for sure, or what rare or long-term side effects it may have. And the FDA does not check research peptides for purity or strength the way it checks approved medicines. That is why this page labels every finding by the kind of study behind it, and lists who should not use it.

Sources for this section

1. 1FDA: How drugs are developed and approved (the FDA does not test drugs; companies submit the evidence)
2. 2FDA: The drug development process, step 3: clinical research (study sizes for each phase)
3. 3Wouters, McKee & Luyten, JAMA 2020, corrected 2022: median cost to bring a new drug to market, $1.14 billion
4. 4US patent law, 35 U.S.C. § 154: a patent lasts 20 years from the filing date
5. 5FDA: Frequently asked questions on patents and exclusivity (5-year new chemical entity exclusivity)
6. 6US Supreme Court, Association for Molecular Pathology v. Myriad Genetics (2013): naturally occurring genes cannot be patented