Peptide Academy · Metabolic

Semaglutide

Also known as GLP-1 receptor agonist

Educational research summary, not medical advice. Many compounds here are not approved for human use. Talk to a licensed clinician before making any health decision.

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What is Semaglutide?

A long-acting GLP-1 analog with extensive human trial data for glycemic and weight outcomes.

How it works

Agonizes the GLP-1 receptor, enhancing glucose-dependent insulin secretion, slowing gastric emptying and reducing appetite signaling in the hypothalamus.

What it has been studied for

~15% average body weight loss (STEP trials)
FDA-approved for chronic weight management (Wegovy)
FDA-approved for type 2 diabetes (Ozempic)
20% reduction in cardiovascular events (SELECT trial)
Appetite suppression via hypothalamic GLP-1 receptors
Slows gastric emptying — reduces hunger duration
Reduces HbA1c and improves glycemic control
Available as injectable (weekly) or oral (daily)

These are effects reported or investigated in research, much of it preclinical. They are not proven outcomes or health claims.

Published research

STEP trials: mean body weight reduction of roughly 15% over 68 weeks
SUSTAIN program for type 2 diabetes glycemic control
SELECT trial showed reduction in major adverse cardiovascular events

Half-life

~165 hours (~7 days)

Cautions

Prescription medication. GI side effects, contraindicated with medullary thyroid carcinoma history.

Side effects & fixes

Common side effects

—Nausea, especially in the first days after starting or raising the dose
—Diarrhea or constipation
—Reduced appetite, early fullness, burping or reflux
—Fatigue and lightheadedness when eating very little
—Mild redness or itching at the injection site

Histamine reactions

Uncommon. Mild injection-site redness or itching can occur; widespread hives or swelling are rare and need urgent care.

Common fixes

Titrate slowly and stay longer at a dose that causes nausea before moving up.
Eat small, low-fat meals, stop at the first sign of fullness, and avoid lying down for 2–3 hours after eating.
Drink plenty of fluids with electrolytes; dehydration makes nausea and fatigue worse.
For constipation, add fiber gradually with extra water; for nausea, ginger or bland foods help many people.
Prioritise protein at each meal to protect muscle while appetite is low.
Rotate injection sites (abdomen, thighs, upper arms) and stay at least an inch from the last spot.

Stop and get help

Severe, persistent stomach pain (possibly spreading to the back) — this can signal pancreatitis or gallbladder problems.
Vomiting or diarrhea that stops you keeping fluids down.
Stop and get emergency help for swelling of the face, lips, tongue or throat, trouble breathing, widespread hives, chest pain or fainting.

Basis: Prescribing information and clinical trials for the GLP-1 class. Educational only, not medical advice.

Medication concerns

From FDA prescribing information

Insulin and sulfonylureas (glipizide, glyburide, glimepiride)
Higher risk of low blood sugar when combined. Prescribers often lower these doses at the start; check your glucose more often.
Medicines taken by mouth (especially levothyroxine, antibiotics, seizure medicines and warfarin)
Slower stomach emptying can delay or reduce how they're absorbed, most of all after the first dose and each dose increase. Ask your prescriber whether timing or monitoring should change.
Birth control pills
Tirzepatide can make pills less reliable when starting and raising the dose; see Birth control & pregnancy on this card.
Diuretics, ACE inhibitors or ARBs (lisinopril, losartan) and NSAIDs (ibuprofen, naproxen)
Vomiting or diarrhea can dehydrate you and strain the kidneys, a risk these medicines add to. Keep fluids up and call your clinician if you can't keep liquids down.
Planned surgery, sedation or endoscopy
Tell the anesthesia team you take this. Food can stay in the stomach longer, which raises aspiration risk under anesthesia.
Other GLP-1-type medicines (semaglutide, tirzepatide, liraglutide and similar)
Don't stack two drugs from this class; it multiplies side effects without proven benefit.
Everything else you take, including supplements
Bring a full list of medicines and supplements to your pharmacist or clinician before starting.

Basis: FDA prescribing information for GLP-1 medicines (semaglutide, tirzepatide, liraglutide, dulaglutide, exenatide); investigational members of the class are assumed to share these until studied. Educational only, not medical advice. Never stop or change a prescribed medicine without your prescriber.

Birth control & pregnancy

Semaglutide (Ozempic, Wegovy, Rybelsus)

Semaglutide's prescribing information reports no clinically significant change in the hormones of a combined birth control pill (ethinyl estradiol and levonorgestrel). Unlike tirzepatide, its label does not call for backup birth control.

—The Ozempic and Rybelsus labels state this directly. The Wegovy label includes the same combined-pill study and contains no backup birth control advice.
—Semaglutide still slows stomach emptying, so vomiting or diarrhea can affect any pill taken by mouth (see below).
—Pregnancy: the labels say to stop semaglutide at least 2 months before a planned pregnancy, because it takes a long time to clear the body.
—Nausea, vomiting and diarrhea are common early side effects. Vomiting or diarrhea soon after taking a birth control pill can reduce how much is absorbed, so ask a pharmacist what your pill's instructions say.

Basis: FDA prescribing information for Ozempic, Rybelsus and Wegovy.

Educational only, not medical advice. Talk with your clinician or pharmacist before changing birth control.

Protocols & tracking are members-only

Members see the research protocols for Semaglutide, plan schedules, track every dose and vial, and ask the AI Advisor questions with cited sources. Try every Researcher feature free for 7 days, no card needed.

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