Split Dose Calculator

Enter your total weekly dose and injection frequency, get the exact dose and syringe units per injection.

Split dose

Steady weekly dosing

Split a weekly dose into even injections for stable blood levels.

Compound

Total Weekly Dose

Injection Schedule

Vial Size (mg)

BAC Water Added (mL)

Dose per Injection

0.500mg

2 injections per week

Track your split protocol in Regimen. Every injection logged, with a reminder for each one.Add to Regimen

Why Split Dosing?

Splitting your weekly dose into multiple smaller injections helps maintain more stable blood levels throughout the week, reducing the peaks and troughs that cause side effects.

This calculator is for informational purposes only, so always double-check your result with a healthcare provider. We assume no liability for dosing errors.

The tool

How it works, what it tells you, what it doesn't.

The split dose calculator helps you divide your weekly TRT or GLP-1 dose evenly across multiple injections. More frequent, smaller injections keep blood levels stable throughout the week, reducing estrogen spikes, mood swings, and GI side effects. Enter your compound, weekly dose, and frequency (2x, 3x, every 3 days, etc.). The optional syringe section calculates units to draw based on your vial concentration.

How to use it

How to Use This Calculator

01

Select your compound

Choose from semaglutide, tirzepatide, testosterone, or retatrutide
02

Enter weekly dose

Your total prescribed weekly dose in mg
03

Pick your schedule

Choose times per week or every X days
04

View your split dose

See per-injection dose and optional syringe units

Why split dosing?

Splitting your weekly dose into multiple smaller injections helps maintain more stable blood levels throughout the week, reducing the peaks and troughs that cause side effects.

For GLP-1 medications (semaglutide, tirzepatide)

Smaller, more frequent doses lower peak drug levels, which can significantly reduce nausea, vomiting, and other GI side effects. Some clinicians prescribe split dosing for compounded semaglutide specifically to improve tolerability during titration.

For TRT (testosterone cypionate, enanthate)

More frequent injections reduce the peak-to-trough ratio, which can lower estrogen conversion (less need for AI), reduce acne and oily skin, and improve mood stability. Most TRT-optimized protocols use at least twice-weekly injections, with some users preferring every-other-day or daily microdosing.

Some people take this further and move to daily microdosing. See our microdosing TRT guide for full daily protocols.

Weekly dose → per-injection

Weekly dose	Twice weekly (÷2)	Every other day (÷3.5)	Daily (÷7)
2 mg (GLP-1 microdose)	1 mg	~0.57 mg	~0.29 mg
7 mg	3.5 mg	2 mg	1 mg
100 mg (TRT)	50 mg	~28.6 mg	~14.3 mg
150 mg (TRT)	75 mg	~42.9 mg	~21.4 mg
200 mg (TRT)	100 mg	~57.1 mg	~28.6 mg

Same math for any compound - divide your weekly dose by shots per week. Use the calculator above for your exact numbers.

Get the app

Track Every Injection in the App

Regimen logs each injection individually, shows pharmacokinetic curves for your protocol, and correlates with health data. Free for one compound.

Visualize blood levels with split dosing
Reminders for each injection day
Track weight, side effects, and progress
Private, secure health data

Free to download. Free for your first compound.

Regimen app Today view with doses and estimated levels

Questions

Frequently Asked Questions

Why should I split my TRT dose into multiple injections?

Splitting your weekly testosterone dose into two or more smaller injections produces more stable blood testosterone levels, reducing the peaks and troughs of once-weekly dosing. Many men report better energy, mood, and libido consistency on twice-weekly injections versus once-weekly at the same total dose.

How do I calculate my split dose?

Divide your total weekly dose by the number of injections per week. For example: 200mg/week split into 2 injections = 100mg per injection. At 200mg/mL concentration, that is 0.5mL per injection. Use the split dose calculator to automatically calculate both the mg per injection and the exact mL volume.

Can I use the split dose calculator for peptides?

Yes. The split dose calculator works for any compound where you want to divide a total weekly dose into multiple smaller injections. This is useful for peptides like BPC-157 or TB-500 that are often dosed twice daily or multiple times per week.

What is the difference between once-weekly and twice-weekly TRT injections?

Once-weekly TRT produces a larger peak after injection and a lower trough before the next dose. Twice-weekly TRT creates a smaller swing, keeping levels more consistent. Most TRT specialists prefer twice-weekly dosing for testosterone cypionate and enanthate. The split dose calculator helps you find the right per-injection volume.

Does splitting TRT doses reduce side effects?

For many patients, yes. High peaks after a single large weekly injection can cause temporary side effects including water retention, elevated hematocrit, or mood swings. Smaller, more frequent doses reduce peak testosterone and estrogen levels, which often improves tolerability and reduces aromatization.

How do I split a 200 mg/week testosterone dose?

Divide the weekly total by the number of injections. Twice-weekly: 100 mg per shot (0.5 mL at 200 mg/mL). Three times per week: about 66.7 mg per shot (0.33 mL). Every other day: about 57 mg per shot (0.29 mL). Daily: about 28.6 mg per shot (0.14 mL). More frequent splits produce more stable blood levels but require smaller, more precise draws.

What is split dosing?

Split dosing means dividing your total weekly dose into multiple smaller injections given throughout the week. Instead of one weekly shot, you might inject twice or three times per week. This maintains more stable blood levels and can reduce side effects.

Is split dosing semaglutide safe?

Some clinicians prescribe split dosing for compounded semaglutide to reduce GI side effects. However, this is an off-label approach. Brand-name pens (Ozempic, Wegovy) are designed for once-weekly use. Always follow your prescriber's instructions.

Why do TRT users split their dose?

Testosterone cypionate and enanthate have half-lives of about 4-5 days. Once-weekly injections cause significant peaks and troughs in blood levels. Splitting into twice-weekly (or more frequent) injections reduces the peak-to-trough ratio, which can lower estrogen conversion, reduce acne, and improve mood stability.

How often should I inject testosterone?

Most TRT protocols work well with twice-weekly injections (e.g., Monday/Thursday or Tuesday/Friday). Some users prefer every-other-day or even daily micro-dosing for the most stable levels. More frequent is generally better for stability, but find a balance that fits your lifestyle.

Does split dosing reduce side effects for GLP-1s?

Some users report that splitting their semaglutide or tirzepatide dose reduces nausea and GI discomfort. By administering smaller amounts more frequently, peak drug levels are lower, which may reduce dose-dependent side effects. However, clinical evidence is limited and this should be discussed with your provider.

What about microdosing GLP-1 medications?

Microdosing typically refers to taking very small doses more frequently than standard protocols. Some users experiment with daily or every-other-day small doses instead of weekly injections. This can help with tolerability during titration but should only be done under medical guidance.

How do I calculate syringe units for split doses?

Use the optional syringe calculation section in this tool. Enter your vial concentration and BAC water amount (for GLP-1s) or mg/mL concentration (for testosterone), and the calculator shows exact syringe units per injection.

Can I use this calculator for other compounds?

This calculator works for any injectable compound where you want to divide a weekly dose. While we show presets for the most common GLP-1s and testosterone esters, the math applies universally. For peptides like BPC-157 or TB-500, see our Peptide Reconstitution Calculator.