Find the line to draw to.

Pick your peptide and fill in the four boxes. The syringe shows exactly where to stop. New to this?

Your line shows up here.

Choose your peptide, then fill in the four boxes.

What do these boxes mean?

In the vial: The amount of powder in the vial before you add anything, e.g. “5 mg”. It’s on the label or the box.
Water added: How much bacteriostatic water you mixed in. It doesn’t change how much peptide you get, only how strong the mix is. More water makes each dose a bigger amount that’s easier to measure.
Your dose: How much peptide you want per injection, from your prescription or plan. Not the number of units on the syringe; that’s what we work out.
Syringe: Check the packet: 1 mL, 0.5 mL or 0.3 mL (sometimes written 100, 50 or 30 units). All are U-100: 100 units is 1 mL. Smaller syringes measure small doses more accurately.

When does this vial expire?

Mixed on

Good for (days)

New to this? It’s three steps.

Peptides usually come as a dry powder. You turn the powder into a liquid, then measure each dose with a small insulin syringe. The calculator does the maths in the middle.

Read the vial label
It says how much powder is inside, such as “5 mg”. That’s the amount in the vial.
Add water and swirl
Let bacteriostatic water run down the inside wall of the vial, then swirl gently until it’s clear. Remember how much you added: that’s the water added.
Draw to the line
Enter both numbers and your dose in the calculator, then pull the plunger back until the stopper’s front edge sits on the line it shows. Back to the calculator

Where to inject

These peptides go just under the skin, into the fat layer, not into muscle. Tap a spot to see how to use it.

Front

Back

Easiest place to start

Belly

Anywhere between the bottom of your ribs and your hip bones, keeping at least 5 cm (2 inches) away from your belly button. Most people find it the least painful spot, and it absorbs steadily.

Skip any spot with a bruise, scar, mole, rash or a lump from an earlier injection.

How to do the injection

The same three steps every time, wherever you inject.

Pinch and go straight in
Wipe the spot and let it dry. Gently pinch up a fold of skin and put the needle straight in. If you’re very lean, go in at an angle instead.
Push slowly, then count to 5
Press the plunger all the way down, slowly. Leave the needle in for about 5 seconds so nothing leaks back out, then let go of the pinch.
Use a new spot next time
Keep each injection a couple of centimetres from the last. Using one spot again and again causes lumps under the skin that absorb unpredictably.

The full checklist

Every step, from a sealed vial to a used needle in the sharps bin.

Wash your hands for 20 seconds and work on a clean surface.
Let the vials reach room temperature, then wipe each rubber top with an alcohol swab and let it dry.
Draw up the water, then let it run slowly down the inside wall of the vial, not straight onto the powder.
Swirl gently until the liquid is completely clear. Don’t use it if it stays cloudy or has specks in it.
Write the date on the vial and keep it in the fridge (2–8 °C). Never freeze a mixed vial.
For each dose: new syringe, swab the vial top, draw to the line the calculator shows, check it against the light.
Inject under the skin of the belly (at least 5 cm from the navel), thigh or back of the upper arm, and move to a different spot each time.
Put the used syringe straight into a sharps container. Never share or reuse needles.

Where the vial came from matters more than the maths

Products sold as “research chemicals” aren’t regulated. Independent tests regularly find the wrong amount, the wrong substance or contamination. A pharmacy product, or at least a seller who publishes independent third-party test results for your batch, is far safer.

Get medical help straight away for trouble breathing, swelling of the face or throat, severe stomach pain, chest pain, or a spreading red, hot area around an injection site.

Words you’ll see

The terms on vial labels, syringe packets and forums, in plain English.

Reconstitute: Mix the powder with water to make a liquid you can inject.
Bacteriostatic (BAC) water: Sterile water with a little preservative (0.9% benzyl alcohol), so one mixed vial can be used for several weeks.
mg and mcg: Milligrams and micrograms. 1 mg is 1,000 mcg, so mixing them up means a dose 1,000 times too big or too small.
Units (on a syringe): The lines printed on an insulin syringe. They measure volume: on a U-100 syringe, 100 units is 1 mL.
IU: International units measure biological activity, and only apply to a few substances like HCG. They are not the same as syringe units.
Strength (concentration): How much peptide is in each mL once it’s mixed. More water means a weaker mix, and a bigger, easier-to-measure dose.
Subcutaneous: Into the fat just under the skin, rather than into muscle. It’s how all of these are injected.
Titration: Starting on a low dose and stepping it up over weeks, so your body can adjust.

Peptides covered

Each page has the calculator set up for that peptide, a units chart, how it’s usually mixed, and what the evidence actually shows.

SemaglutideApproved drug
TirzepatideApproved drug
RetatrutideInvestigational
HCGApproved drug
BPC-157Animal studies only
TB-500Animal studies only
CJC-1295 (no DAC)Limited human evidence
IpamorelinLimited human evidence
CJC + Ipa BlendLimited human evidence
TesamorelinApproved drug
SermorelinLimited human evidence
GHK-CuLimited human evidence
EpithalonLimited human evidence
PT-141Approved drug
Melanotan IILimited human evidence
NAD+Limited human evidence

Compare two peptides side by side

Guides

Longer reads for when you want the why, not just the number.

Semaglutide reconstitution: how to mix and measure a vial
How much water to add to a semaglutide vial, how many units a dose is, the approved step-up schedule, and how to store it.
Syringe sizes explained: 0.3 mL, 0.5 mL and 1 mL
30, 50 and 100 unit insulin syringes: what the lines mean, why a dose is the same number of units on all three, and which one to use.

Questions

Are syringe units the same as IU?

No. Units on an insulin syringe are a volume: on a U-100 syringe, 100 units is 1 mL. IU (international units) measure biological activity and only apply to a few substances, such as HCG. Mixing them up is one of the most common dosing mistakes.

Why does it say a whole number when the exact amount isn’t?

Syringes only have lines every 1 or 2 units, so we show the nearest line you can actually draw to, plus the exact volume. When the exact amount sits halfway between two lines we round down, never up. If the nearest line is more than 10% off, we tell you and suggest a smaller syringe or more water.

How accurate is this?

The arithmetic is tested against every peptide, vial size and dose we list. It can only be as right as what you enter, though: the amount on the vial label and the water you added. Products sold as research chemicals often don’t contain what the label says, and no calculator can correct for that.

Can I use sterile water instead of bacteriostatic water?

Sterile water has no preservative, so it is meant for a single use. Bacteriostatic water contains 0.9% benzyl alcohol, which is why a vial mixed with it can be used for several weeks.

How long does a mixed vial last?

Most last about four weeks in the fridge (2–8 °C) when mixed with bacteriostatic water. Don’t freeze a mixed vial. The expiry tracker in the calculator will work out the date for you.

Which syringe size should I use?

The smallest one your dose fits in. Under about 30 units, a 0.3 mL syringe is marked more finely and is more accurate. Up to 50 units, use 0.5 mL. Above that, 1 mL.

Should I shake the vial?

Swirl it gently instead. Shaking hard makes foam that is difficult to measure through and may damage some peptides.

Supplies

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