Semaglutide, or sema.
What the compound is, the vial sizes that show up on real labels, how to turn the mg printed on that label into units on a syringe, how to store it, and what tracking a semaglutide protocol actually looks like in Protocol Her.
- Compound class
- GLP-1 receptor agonist
- In the Protocol Her library as
- Semaglutide
- Doses entered in
- mg
- A new schedule starts at
- Once a week
- Powder vial sizes commonly seen
- 2 mg, 5 mg, 10 mg
The classification badge describes the molecule's regulatory status, which is what the app displays. It says nothing about any individual vial, seller, or compounded preparation.
A GLP-1 receptor agonist, plainly.
Semaglutide is a lab-made peptide designed to resemble GLP-1, a hormone the gut releases after a meal. It binds the same receptor the natural hormone does, and it was engineered to last far longer in the body than the hormone itself, which is why it is given weekly rather than several times a day.
Where you meet it
Semaglutide is the active ingredient in FDA-approved prescription products sold under brand names, each cleared for the specific uses printed on its own label. It also circulates as compounded and research-labeled powder outside that supply chain. These are not interchangeable, and they are not held to the same manufacturing standards.
Why the shorthand
Sema is what people type. It is not a different molecule, a strength, or a brand, just a four-letter contraction that survives group chats. Protocol Her lists the full name, Semaglutide, and its search box matches what you actually type.
What this page will not do
It will not tell you an amount, a schedule, how much water to add, or where to buy anything, and it makes no claim about what semaglutide will do for you. Those belong with a clinician who knows your history. What follows is arithmetic and handling.
What the label actually says.
Two very different formats travel under the same name, and only one of them involves any math at all.
Prefilled pens
Prescription semaglutide is dispensed as a pen holding a liquid that is already prepared. The pen's own dial handles the measuring, there is nothing to reconstitute, and none of the conversion below applies. Follow the instructions that came in the box.
Powder vials
Compounded and research-labeled semaglutide is usually a freeze-dried powder. Labels most often read 2 mg, 5 mg, or 10 mg of peptide in the vial. That number is a total mass, not a strength: until liquid is added, there is no such thing as mL or units.
Read the mg figure off your own vial every time rather than assuming it matches the last one. Protocol Her deliberately ships no preset vial sizes for any compound, because the only number that is true is the one printed on the vial in front of you.
From mg on the label to units on the barrel.
Take a 5 mg vial with 2 mL of bacteriostatic water added, and say you want to measure 0.6 mg. Every number here was picked to make the arithmetic easy to follow. None of them is a suggested vial size, water volume, or amount.
Concentration
Divide the peptide in the vial by the water you added. That is the strength of every mL in the finished solution.
5 mg ÷ 2 mL = 2.5 mg/mL
Volume
Divide the amount you want by the concentration. That gives the volume of liquid holding it. Semaglutide is entered in mg, so no unit conversion is needed first.
0.6 mg ÷ 2.5 mg/mL = 0.24 mL
Syringe units
A U-100 insulin syringe is marked at 100 units per mL, so multiply by 100 to read the same volume on the barrel.
0.24 mL × 100 = 24 units
Same vial, more water: 5 mg in 5 mL is 1 mg/mL, and that same 0.6 mg becomes 0.6 mL, or 60 units. The vial still holds 5 mg either way. Water changes how an amount is measured, never how much peptide is there.
Run your own numbers in the free calculatorPeptides are fragile proteins.
Heat, light, and agitation are what degrade them. General handling principles below. Your product's own label and your pharmacist override every one of them.
- Before mixing, the powder is the stable form. Freeze-dried peptide keeps far better than solution. Store it as its label directs, away from light and heat.
- Once liquid is added, it is refrigerated. Reconstituted peptide belongs in the fridge, upright, not in the door where the temperature swings every time it opens.
- Do not freeze a reconstituted vial. Ice crystals damage peptide in solution. Freezing and rethawing is not a way to extend anything.
- Add water gently and do not shake. Run the stream down the inside wall of the vial and swirl slowly. Foaming means agitation, and agitation denatures protein.
- Bacteriostatic water is not sterile water. Bacteriostatic water contains a preservative, benzyl alcohol, which is what allows a vial to be entered more than once. Sterile water has none. They are not interchangeable.
- Write the date you mixed it on the vial. A date on the label beats memory. Discard a vial that is cloudy, discolored, or has anything floating in it.
- Pens follow their own rules. Prefilled prescription pens have manufacturer storage and in-use limits printed on the carton. Use those, not general peptide guidance.
Protocol Her records the date you reconstituted a vial and seeds a discard date 28 days later, a common convention rather than an expiry the app is asserting. The date is yours to change, and the app never claims a beyond-use date on your behalf.
Tracking a sema protocol, exactly as it ships.
Semaglutide is one of 35 compounds in the app's library. Picking it sets up the frame: the category, the classification badge, the unit your doses are entered in, and a starting cadence. Every number stays yours to enter.
A schedule you set
A new semaglutide schedule opens on Once a week, since weekly is intrinsic to how this compound is given. You can move it to every day, every other day, twice a week, every 2 weeks, or as needed, then pin a weekday and a time.
Doses in mg, with the site
Each logged dose carries the amount in mg, the time, and one of seven injection sites: left or right abdomen, thigh, or arm, plus glute. The body map remembers where the last ones went, so rotating stops being a memory game.
The vial, tracked
Log the mg and the water you added and the app carries the concentration forward: doses remaining, a low-stock signal, cost per dose, and the reconstitution and discard dates. The same conversion runs on a live U-100 syringe gauge.
Metabolic check-ins
Because semaglutide sits in the Metabolic category, the daily card offers weight, energy, hunger, protein, and body measurements. Side effects log with a 1 to 5 severity, from nausea and fatigue to headache and sleep.
Cycle context and co-factors
Log your period and doses and symptoms are placed in cycle-phase context. Semaglutide also carries educational co-factor notes on protein, electrolytes, fiber, and a multivitamin, with the reasoning shown rather than asserted.
A record you can hand over
Weeks on the protocol are counted from what you logged, never prescribed ahead of you. Export the history as a clinician-ready PDF or a data file whenever you want it.
All of it stays on your iPhone. There is no account and no server copy of what you log, and reminders never name a compound or an amount on your lock screen. What the app does not do is equally deliberate: it ships no dose ladder, no vial presets, and no water volumes for semaglutide or anything else.
Common questions, answered.
What does sema mean?
Sema is everyday shorthand for semaglutide, the same way tirz stands for tirzepatide and reta for retatrutide. It is not a separate compound, a brand, or a different strength. People use it because the full name is long.
Does semaglutide always need mixing?
No, it depends on the form. Prescription pens arrive as a prepared liquid, so there is nothing to mix and no conversion to do. Freeze-dried powder in a vial has to be dissolved before any amount can be measured, which is where mg, mL, and units come in.
How do I turn mg into syringe units?
Divide vial mg by the mL of water added for the concentration, divide your amount by that concentration for a volume in mL, then multiply by 100 for a U-100 syringe. The free calculator runs the same chain and prints every step.
How is semaglutide different from tirzepatide?
Semaglutide acts on the GLP-1 receptor alone. Tirzepatide acts on two, GIP as well as GLP-1, and retatrutide adds a third. They are different molecules with different labels and different regulatory standing.
The rest of the library.
Track it where it stays yours.
Protocol Her keeps doses, vials, symptoms, cycle, and labs in one place, with the reconstitution calculator and a live U-100 syringe gauge built in. Free to download, no account to create.
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