How Intranasal Peptide Calculations Work
A plain-language guide to vial size, saline volume, spray volume, and dosage per spray — for anyone preparing peptides for intranasal administration.
If you've found your way here, you probably already know what peptide you're working with. What's less clear is the preparation math — how much saline to add, what concentration that creates, and how much peptide each spray actually delivers.
That math is straightforward once you understand the four inputs. This page walks through each one, explains the units, shows the formula, and links to the calculator that handles it automatically.
How Intranasal Peptide Administration Works
Intranasal administration means delivering a compound through the nasal mucosa rather than by injection or oral ingestion. For certain peptides, this route offers a practical advantage: the nasal cavity provides proximity to the olfactory pathway, a direct channel that bypasses the blood-brain barrier and allows compounds to reach CNS targets more rapidly than systemic routes.
This nose-to-brain delivery mechanism is part of why intranasal peptide administration has attracted research interest for compounds like Semax, Selank, and Oxytocin — peptides that would otherwise be degraded before reaching their target via oral routes.
Preparation accuracy matters here precisely because the delivery route is direct. Concentration errors don't get averaged out across a digestive system. What you prepare is what gets delivered.
The Four Numbers That Matter
Every intranasal peptide calculation comes down to four inputs:
How much peptide is in your vial, measured in milligrams (mg). Typically printed on the vial label.
How much saline you add to the vial, measured in milliliters (mL). This is the number you control, and it determines concentration.
How much liquid your spray bottle delivers per pump, in mL. This varies by bottle and is not always accurate as labeled.
How much peptide you want delivered per actuation, measured in micrograms (mcg). This is the target your calculation works backwards from.
Everything else is derived from these four.
The Units Explained
mg vs mcg
Milligrams and micrograms are both units of mass, but they differ by a factor of 1,000.
Peptide vials are labeled in milligrams. Dosage targets are expressed in micrograms. Confusing the two is the most common — and most consequential — preparation error. Always confirm which unit you are working in before calculating.
mL
Milliliters measure liquid volume. When you add saline to a vial, you are working in mL. When your spray bottle pumps, it delivers a fixed volume in mL per actuation. These two values — total saline volume and spray volume — are what connect your peptide amount to your dosage per spray.
mcg per spray
This is the number that matters for preparation accuracy. It describes how much peptide is delivered each time the pump actuates. It is not printed on anything — it is calculated.
The Basic Formula
Intranasal peptide calculations follow three steps.
Total peptide (mg) ÷ Total saline volume (mL) = Concentration (mg/mL)
Concentration (mg/mL) × Spray volume (mL) = Dosage per spray (mg)
Dosage per spray (mg) × 1,000 = Dosage per spray (mcg)
Total peptide (mcg) ÷ Dosage per spray (mcg) = Total sprays available
Or work backwards from a target:
Target dose (mcg) ÷ Dosage per spray (mcg) = Sprays needed per dose
A Worked Example
A vial contains 10mg of peptide. A researcher adds 5mL of saline. The spray bottle delivers 0.1mL per pump.
This example uses round numbers to illustrate the mechanics only. It is not a dosage recommendation for any peptide or protocol.
Why Spray Volume Matters
The example above assumes the spray bottle delivers exactly 0.1mL per pump. That assumption carries significant weight.
In practice, spray output varies between bottle types, pump designs, and even individual actuations. A bottle delivering 0.12mL instead of 0.1mL delivers 20% more peptide per spray than calculated — in this example, 240mcg instead of the intended 200mcg. Across a full vial that variance compounds meaningfully.
Spray volume consistency is the part of intranasal peptide preparation that gets the least attention and causes the most silent errors. If the spray volume input is wrong, every number downstream is wrong.
This is why Spirare Supply focuses on verified, consistent atomizer output. Preparation math is only as accurate as the hardware running it.
Common Mistakes
1mg = 1,000mcg. A vial labeled 10mg contains 10,000mcg. A target of 200mcg is 0.2mg. These conversions are simple but easy to invert. Always verify the unit before calculating.
0.1mL is a common standard, not a universal one. Unverified atomizers can vary significantly from their stated output. Verify actual delivery volume before relying on any calculation.
Adding more saline changes the concentration of the entire solution. In the example above, adding 6mL instead of 5mL would drop the dosage per spray from 200mcg to 167mcg — a meaningful difference. If you adjust liquid volume, every downstream number needs to be recalculated from scratch.
Frequently Asked Questions
What is the difference between mg and mcg?
How do intranasal peptide calculations work?
Why does spray volume matter so much?
How do I calculate how many sprays I need for a target dose?
What does intranasal peptide administration mean?
Use the Calculator
The Intranasal Peptide Calculator handles all of the above automatically. Enter your vial size, target dosage per spray, and spray volume — it returns the exact saline volume to add, your dosage per spray, and total sprays available.
Use the Intranasal Peptide Calculator →