Calculator

How many clicks is 2mg on a Retatrutide 40mg pen?

Short answer: 15 clicks. On the standard 40mg Retatrutide pen (3 mL cartridge, 300 clicks), 2mg is 15 clicks, 2.5mg is 18.75 clicks, and 1mg is 7.5 clicks. Use the calculator below for any other dose, pen size, or peptide — including GHK-Cu, Tirzepatide, NAD+, L-Glutathione, GLOW and KLOW pens.

Inputs

Pen preset

Pick a preset to auto-fill mass, cartridge and common dose.

Calculation direction

Pen total mass

Pen mass (mg)

Cartridge volume

Cartridge volume (mL)

Total clicks on pen dial

clicks

Standard reusable pens are 300 clicks.

Target dose

Dose (mg)

Pen price (optional, for cost-per-dose)

Leave at 0 to skip the cost-per-dose calculation.

Results

Concentration

13.33 mg/mL

Dial position

7.5 clicks

Volume per dose

0.075 mL

Doses remaining

~40

One full pen at this dose

40 × 1.000 mg

Dial pen to 7.5 clicks for injection, or draw 7.5 units on a U-100 refill syringe (0.075 mL).

Calculations run entirely in your browser; no inputs leave your device. For laboratory / research-stage reference only.

Reference table — every common pen preset

Click any row to load that preset into the calculator above. Sort by any column.

Pen ↑	Mass	Cartridge	mg/mL	Common dose	Clicks
GHK-Cu 100 mg pen	100 mg	3 mL · 300 clicks	33.33	3 mg	9.0
GHK-Cu 200 mg pen	200 mg	3 mL · 300 clicks	66.67	3 mg	4.5
GLOW (50/10/10) 70 mg penTotal blend mass; dose is per-blend not per-component	70 mg	3 mL · 300 clicks	23.33	3.5 mg	15.0
KLOW (10/10/50/10) 80 mg penTotal blend mass; dose is per-blend not per-component	80 mg	3 mL · 300 clicks	26.67	4 mg	15.0
L-Glutathione 1800 mg pen	1800 mg	3 mL · 300 clicks	600.00	200 mg	33.3
NAD+ 1000 mg pen	1000 mg	3 mL · 300 clicks	333.33	100 mg	30.0
NAD+ 1800 mg pen	1800 mg	3 mL · 300 clicks	600.00	200 mg	33.3
Retatrutide 24 mg penTitration / starting dose tier	24 mg	3 mL · 300 clicks	8.00	0.5 mg	6.3
Retatrutide 40 mg pen	40 mg	3 mL · 300 clicks	13.33	1 mg	7.5
Retatrutide 60 mg pen	60 mg	3 mL · 300 clicks	20.00	2 mg	10.0
Semaglutide 15 mg penWeekly titration; starting tier	15 mg	3 mL · 300 clicks	5.00	0.25 mg	5.0
Tesamorelin 20 mg pen	20 mg	3 mL · 300 clicks	6.67	1 mg	15.0
Tirzepatide 40 mg pen	40 mg	3 mL · 300 clicks	13.33	2.5 mg	18.8
Tirzepatide 68 mg pen	68 mg	3 mL · 300 clicks	22.67	5 mg	22.1

Key facts: Retatrutide 40mg pen clicks

A 40mg Retatrutide pen holds a 3 mL cartridge with 300 total dial clicks — 0.133 mg per click.
2mg is 15 clicks. 2.5mg is 18.75 clicks. 1mg is 7.5 clicks.
A dial only stops on whole clicks, so a fractional result has to be rounded to the nearest dial position.
GHK-Cu peptide pens use the same 300-click dial standard, at 100mg or 200mg cartridge sizes.
Retatrutide is not approved for human use; every figure here is laboratory dial-position arithmetic only.

How many clicks on a 40mg Retatrutide pen?

On a 40mg Retatrutide pen (3 mL cartridge, 300 total clicks), the dial position scales directly with the target dose: clicks = (dose mg ÷ 40) × 300. The table below is a retatrutide dosage calculator 40mg pen quick reference for the most commonly researched doses — enter any other value into the calculator above for the exact figure.

Figures below are exact arithmetic. A pen dial only stops on whole clicks, so round a fractional figure to the nearest dial position.

Dose	Clicks (40mg pen, 300 clicks)
1 mg	7.5
2 mg	15
2.5 mg	18.75
5 mg	37.5

How many clicks is 1 mg of Retatrutide pen?

1mg on a 40mg / 300-click pen is 7.5 clicks — see the table above, or enter 1 into the calculator's dose field above for the exact dial position and U-100 syringe equivalent.

GHK-Cu peptide pen dosage

GHK-Cu pre-mixed pens follow the same 300-click dial standard as the Retatrutide pens above. On a 100mg GHK-Cu pen, a 3mg research dose is 9 clicks; on a 200mg GHK-Cu pen, the same 3mg dose is 4.5 clicks, which rounds to the nearest whole dial position. Pick either GHK-Cu preset in the calculator above to load the exact figures.

How the maths works

A reusable injection pen has two key numbers stamped on the cartridge: the total peptide mass (for example 40 mg of Retatrutide) and the cartridge volume (almost always 3 mL on modern reusable pens). The dial mechanism breaks that 3 mL into a fixed number of graduated clicks. 300 is the standard on the cartridges supplied by research-grade vendors. Each click advances the piston by 0.01 mL.

That means the concentration is fixed at penMg / cartridgeMl mg/mL, and the click count required to deliver a target dose is (doseMg / penMg) * totalClicks. The calculator above evaluates both formulas live as you type, and the visual dial mirrors the result so the dial position is unambiguous when you transfer the math to the physical pen.

For the common Retatrutide 40 mg / 3 mL / 300-click pen, each click is about 0.133 mg. That makes 1 mg equal 7.5 clicks, 2.5 mg equal 18.75 clicks, and 5 mg equal 37.5 clicks for research calculations.

Where the Retatrutide dose range comes from

Retatrutide is a triple GIP/GLP-1/glucagon receptor agonist in late-phase (Phase 3) clinical trials for weight-loss research, including a trial reported in the New England Journal of Medicine (Jastreboff AM et al., 2023) that used weekly dosing and progressed participants toward a research dose as high as 12mg. Retatrutide is not approved for human use anywhere, and every number on this page is dial-click and volume arithmetic only — it does not predict physiological effects. For a full week-by-week titration ramp (4, 8, or 12 weeks) instead of a single dial position, use the Protocol Simulator.

Reverse mode

Sometimes a researcher knows the dial position they want to fix on (for example, an even 10 clicks for simple counting) and needs to know what dose that delivers. Toggle Clicks to dose on the calculator to flip the math direction.

Pre-mixed combo pens

Some healing blends, notably KLOW (10/10/50/10) and GLOW (50/10/10), are increasingly supplied as pre-mixed cartridges. For these the per-click dose refers to the blend total; the individual component masses scale proportionally. For per-component breakdowns of a single multi-peptide draw, use the Dosage Calculator in combo mode.

Related tools

Dosage Calculator for vial + BAC water reconstitution rather than pre-mixed pens.
Reconstitution Calculator for the underlying mg-to-mcg-per-mL conversion.
Half-Life Calculator for choosing the right dosing interval for the peptide in your pen.

Frequently asked questions

How do I work out the dial-click count for my peptide pen?

Clicks = (target dose in mg / pen total mass in mg) * total clicks on the dial. The calculator does this for you with a single click of a preset, or you can enter the values manually.

How many clicks per mg on a 40 mg Retatrutide pen?

A 40 mg Retatrutide pen with 300 clicks delivers 0.133 mg per click, so a 1 mg research dose is 7.5 clicks, and a 2 mg dose is 15 clicks.

How many clicks is 2.5 mg from a 40 mg Retatrutide pen?

On a standard 40 mg Retatrutide pen with 300 clicks, 2.5 mg is 18.75 clicks. Most researchers round this to the nearest dial position according to their laboratory protocol.

How many doses does one Retatrutide 24 mg pen contain at a 2 mg research dose?

24 mg / 2 mg per administration = 12 full research doses per pen. Lower starting-dose protocols (0.5 mg) yield about 48 doses from the same pen.

Why does the calculator show both a click count and a U-100 unit count?

Some researchers prefer to dial the pen directly; others transfer the dose into a standard U-100 insulin syringe. Both numbers come from the same draw volume, so either approach delivers identical research dose mass.

Does the cost-per-dose figure include any sourcing margin?

No, it is simply your pen price divided by the number of full doses the pen can deliver at the chosen dose level. Use it for laboratory budgeting only.

Can I save my pen presets between visits?

Use the "Copy share link" button to capture a URL containing every input. Bookmark or share that link to restore the exact configuration. Nothing is stored on our servers.