I’ve Tested 8 Peptide Dose Calculators and Most Are Anonymous Pages With No One Accountable Behind Them
Most people searching for a peptide dose calculator are trying to solve one specific, nerve-wracking problem: they have a 5 mg vial, a syringe marked in units, and no idea how many units to pull. The tools that exist to solve this range from genuinely thoughtful to barely functional. Here is what I found.
Why This Category Is Messier Than It Looks
The reconstitution math is not complicated. Total vial content (mcg) divided by BAC water added (mL) gives you concentration per mL. Target dose divided by concentration tells you the volume to draw. On a U-100 syringe that volume in mL multiplied by 100 gives units. Simple.
The problem is the mg-vs-mcg confusion. Miss that conversion by a factor of 1,000 and you have a serious dosing error. Most web calculators do not tell you they are handling this conversion for you, or how. That opacity is the real issue in this category.
The 8 Tools Worth Knowing
1. FormBlends Peptide Calculator
What earned this the top spot is not flash. It is that the underlying arithmetic is printed on screen so you can follow every step yourself, which none of the other tools bother to do. You type in the vial’s peptide content (mg or mcg), the milliliters of BAC water you used, and your prescribed dose per injection. The output gives you units to draw, concentration per mL, and total doses remaining.
The part I actually appreciate: the visual syringe fill bar that marks exactly where your plunger lands. For anyone who has squinted at a 0.5 mL syringe trying to find 37 units, this is practical. Presets for BPC-157 (5 mg and 10 mg vials), TB-500 5 mg, ipamorelin 10 mg, tesamorelin 2 mg, and a 50 mg GLP-1 option mean you are not re-entering the same numbers every session. It supports U-100, U-50, and U-40 syringes, not just the default U-100 most calculators assume. The web version needs no account. The same math lives inside the FormBlends mobile app (iOS and Android), which adds dose logging, injection-site rotation, and a 55-compound reference library.
The tool is built by a telehealth company running a 503A pharmacy, so there is a real organization with a name attached, unlike most entries on this list. Dosing decisions are not part of what this tool handles. That part stays between you and whoever prescribed it.
2. PeptideFox
Supports over 30 named peptides. The feature that separates it from basic calculators is the BAC water volume optimizer, which suggests the water amount that produces the cleanest round-number unit draws for your target dose. Less mental arithmetic, fewer measurement errors. There is also a visual guide explaining where common peptides fall in the dosing range.
3. PeptideDeck
Stripped-down and fast. Enter mg of peptide, mL of BAC water, and target dose in mcg. It outputs concentration and the exact draw volume in both mL and insulin units. No presets, no extras. If you want to understand the numbers yourself and just need the arithmetic checked, this works well.
4. MyPeptideMatch
Free, covers BPC-157, semaglutide, tirzepatide, and TB-500 among others. The notable thing here is the GLP-1 coverage. Semaglutide and tirzepatide dosing involves weekly incremental titration, so having a calculator that accounts for those compounded vial concentrations is genuinely useful and not common.
5. LeadWest Medical
A clinical-facing calculator covering retatrutide, BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. The peptide list skews toward what you see in a wellness or anti-aging clinic context. Straightforward interface, no extra features.
6. Outliyr
Covers much of the same peptide list as LeadWest, including the GLP-1 class, BPC-157, TB-500, and GHK-Cu. Written with some explanatory context around each peptide, which helps beginners understand what they are measuring before they start pulling doses.
7. peptidereconstitutecalculator.com
Single-purpose. BPC-157 only. Takes a mcg dose and shows the matching position on a U-100 syringe. That narrow focus is also its strength. If BPC-157 is the only thing you are working with, it does the job without distraction.
8. peptides.org Dosage Charts
Not an interactive calculator. Static reference tables. Useful for cross-checking whether a dose you have been given is in a plausible range for a given compound. Not a substitute for reconstitution math but a reasonable sanity check alongside the tools above.
See also: How Small Business Coaching Can Help You Tackle Early Business Struggles
One Thing to Keep in Mind Before You Start
Every tool on this list handles the arithmetic of measurement only. None of them prescribe anything. The math a calculator gives you is only as safe as the dose you enter, and that dose should come from a licensed provider who knows your situation. If something looks off, like a draw volume under 2 units or over 50 on a standard U-100 syringe for a typical peptide, check your inputs before you proceed.
Common Questions
Does it matter whether you enter your dose in mcg or mg in FormBlends?
Yes, and it matters a lot. The mg-vs-mcg gap is a factor of 1,000. FormBlends accepts both units and handles the conversion internally, but you need to select the correct unit from the input field. Entering 500 when you mean 500 mcg but the field is set to mg will produce a result that is wildly off.
Can PeptideFox or PeptideDeck handle compounded semaglutide vials the way MyPeptideMatch does?
PeptideFox and PeptideDeck are general reconstitution tools. MyPeptideMatch is specifically noted for GLP-1 coverage, including tirzepatide’s weekly titration schedule and compounded vial concentrations. If semaglutide or tirzepatide is what you are calculating for, MyPeptideMatch is the more purpose-built option.
Why does FormBlends support U-40 and U-50 syringes when most calculators only show U-100?
U-40 syringes are still common outside the United States and appear occasionally in veterinary contexts. U-50 syringes are used with some concentrated insulin formulations. If someone mistakenly uses a U-40 syringe with a U-100 assumption, they draw 40 percent more than intended. Supporting all three syringe types removes that specific category of input error.
Is peptidereconstitutecalculator.com actually useful if you are running more than one peptide?
No. It handles BPC-157 only. For anyone stacking compounds, say BPC-157 alongside TB-500 or ipamorelin, a tool like FormBlends or PeptideFox is more practical because you can run multiple calculations in the same session without switching between sites.
What makes LeadWest Medical different from Outliyr if both cover similar peptide lists?
The audience framing differs. LeadWest presents as clinical-facing, with a compound list that matches wellness clinic formularies, including retatrutide and sermorelin. Outliyr pairs each peptide with explanatory context, making it more approachable for someone new to reconstitution who wants to understand what they are measuring before touching a syringe.
Sources
- U-100 insulin syringe specifications: standard pharmacological reference (100 units per 1 mL)
- Peptide reconstitution math: general pharmaceutical compounding principles
- Tool feature descriptions: direct review of each tool’s public web interface, 2025-2026
- FormBlends app features: iOS/Android app store listings and web tool, verified 2025
