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Peptide nasal spray calculator
How much peptide is in each spray, how many sprays a dose takes and how long the bottle lasts once priming and the pump's leftovers are counted.
Not sure? Measure your pump
Prime the pump, set a small cup on a kitchen scale that reads to 0.01 g, tare it, then fire a counted number of sprays into it. A water-based solution weighs close to 1 g per mL, so the weight divided by the sprays is the mL per spray.
The short answer
Amount per spray = peptide ÷ liquid × spray volume. 10 mg in 10 mL is 1 mg/mL. A 0.1 mL spray then carries 100 mcg, so a 200 mcg dose is 2 sprays.
Two things most calculators leave out. A pump only fires whole sprays, so many doses cannot be hit exactly. And a bottle gives fewer sprays than its volume suggests, because priming and the liquid the pump cannot reach both come out of it.
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How much actually gets in
Two peptide nasal sprays approved in the US show how big the gap between a spray and an injection can be.
- Calcitonin. The Miacalcin nasal spray label puts its bioavailability at about 3% of the injection, with a range between people of 0.3% to 30.6%.
- Desmopressin. Its spray label notes that a 2 mcg injection gives about 20 times the exposure of a 10 mcg spray.
Both of those are formulated products made to be absorbed through the nose. A review of intranasal peptides by Al Bakri and colleagues notes that permeation enhancers and mucoadhesives have shown promise in improving how much peptide gets through. A peptide dissolved in plain or bacteriostatic water has neither. For the peptides most often mixed into home sprays there is very little to go on. We could not find a published study measuring how much BPC-157 is absorbed through the human nose. The Selank tracer work is in rats: Ashmarin and colleagues found the nasal route delivered it to the brain better than the other routes they tested. That is the reason people use the nose for these peptides, but it is not a human dose.
Absorption also changes with the state of your nose. The desmopressin label warns that scarring, swelling, congestion or recent nasal surgery can make absorption erratic. A dose that seemed to work on a clear day may not on a blocked one.
So the honest summary: the calculator is exact about what leaves the bottle. Nobody can tell you what reaches your blood from a home-mixed spray. An injected dose does not translate into a number of sprays either.
Whole sprays mean doses move in steps
A metered pump fires a fixed volume, so your dose can only be one spray, two sprays, three sprays and so on. The desmopressin label is blunt about this: the product is not for anyone who needs less than 10 mcg or a dose that is not a multiple of 10 mcg, because the pump can only deliver 10 mcg at a time.
If your dose falls between two spray counts, the only ways to land on it are a different concentration or a pump with a different spray volume. The calculator shows how far each neighboring spray count is from the dose, so you can see the size of the gap before deciding anything with whoever set the dose.
Why the bottle runs out early
Two things come out of the bottle that never reach your nose.
- Priming. A new pump has to be primed until it fires a full mist. The desmopressin label says 4 sprays and 1 more if the pump has sat unused for a week. The Miacalcin label says to pump until the first full spray appears.
- Liquid the pump cannot reach. The dip tube cannot draw the last of the solution. Miacalcin is a clear example. Its bottle is filled with 3.7 mL, yet the label promises only at least 30 sprays of 0.09 mL, which is 2.7 mL. It tells patients to count their doses because after 30 each spray may not deliver the correct amount, even if the bottle is not empty. The desmopressin label likewise says to throw the bottle away after 50 sprays for the same reason.
Approved products tell you the usable count. A generic spray bottle does not, which is why the calculator lets you enter the unusable volume. If you measure what is left when the spray starts to sputter, put that number in for the next bottle.
Worked examples
The same arithmetic the calculator runs, with 4 priming sprays and the unusable volume set to 0.
| Bottle | Per spray | Dose | Sprays | Doses per bottle |
|---|---|---|---|---|
| 10 mg in 10 mL 0.1 mL pump | 100 mcg | 200 mcg | 2 | 48 |
| 5 mg in 5 mL 0.1 mL pump | 100 mcg | 300 mcg | 3 | 15 |
| 10 mg in 3 mL 0.1 mL pump | 333 mcg | 500 mcg | 1 gives 333 mcg (−33%), 2 give 667 mcg (+33%) | 26 at 1 spray, 13 at 2 |
| 2 mg in 5 mL 0.09 mL pump | 36 mcg | 100 mcg | 3 give 108 mcg (+8%) | 17 |
The doses are there to show the arithmetic. They are not dose recommendations. At 1 dose a day the first bottle would last 48 days, well past either beyond-use limit below, so in practice the calendar ends it first.
How long a mixed spray is good for
No one has tested the stability of a peptide you dissolved at home, so there is no true expiry date. The nearest benchmark is the rule pharmacies follow. USP chapter 795, which governs compounded nonsterile preparations such as nasal sprays, sets default beyond-use limits for water-based preparations:
| Water-based preparation | Default limit | Storage |
|---|---|---|
| No preservative | 14 days | Refrigerator |
| With a preservative | 35 days | Room temperature or refrigerator |
The chapter also says a shorter date applies when the ingredient itself is less stable than that. Peptides in solution can be. So treat these as ceilings rather than promises. If you do not know whether your liquid contains a preservative, use 14 days. The calculator warns when the bottle would outlast the limit you picked. The peptide storage guide covers what breaks peptides down in solution.
Hygiene matters too. The nozzle goes into your nose every time, so do not share a bottle. In the calcitonin trials, changes in the lining of the nose turned up in up to 9% of people on the drug and up to 12% on the placebo spray, so spraying alone is enough to irritate some noses. The label recommends a nasal examination whenever nasal symptoms appear.
Frequently asked questions
How do I work out how much peptide is in one spray?
Divide the peptide by the liquid to get the concentration, then multiply by the volume your pump sprays. Approved sprays such as desmopressin deliver 0.1 mL per spray. 10 mg in 10 mL is 1 mg/mL, so a 0.1 mL spray carries 0.1 mg, which is 100 mcg.
Is a nasal spray dose the same as an injected dose?
No. Much less of a peptide reaches the blood through the nose. The US label for calcitonin nasal spray puts its bioavailability at about 3% of the injection, with a range from 0.3% to 30.6% between people. This calculator tells you how much leaves the bottle, not how much you absorb. It does not convert an injected dose into a nasal one either.
Why can I not get my exact dose?
A pump delivers whole sprays, so the dose moves in steps of one spray. The desmopressin nasal spray label says so directly: its pump can only deliver doses of 10 mcg. If your dose falls between two spray counts, the calculator shows how far each one is off.
How many sprays are in a nasal spray bottle?
Fewer than the volume suggests. Priming a new pump uses several sprays and the pump cannot draw the last of the liquid. Calcitonin nasal spray comes in a 3.7 mL bottle but its label promises at least 30 sprays of 0.09 mL, which is 2.7 mL. It warns that sprays after that may not deliver the right amount.
How long does a homemade peptide nasal spray last?
There is no tested answer for a home mix. The pharmacy rules in USP chapter 795 cap a compounded water-based spray at 14 days in the fridge without a preservative and 35 days with one, unless stability testing supports longer. Treat those as upper limits. If you do not know whether your liquid is preserved, use 14 days.
Sources
- Novartis Pharmaceuticals. Miacalcin (calcitonin-salmon) Nasal Spray prescribing information, July 2011 (FDA): bioavailability about 3% of injection (range 0.3% to 30.6%), 200 units per 0.09 mL spray, 3.7 mL fill with at least 30 doses, priming, 35 days at room temperature once in use, nasal adverse events with drug and placebo.
- Apotex. Desmopressin Nasal Spray prescribing information, revised 9/2022: 10 mcg per 0.1 mL spray, doses only in multiples of 10 mcg, prime 4 times, discard after 50 sprays, a 2 mcg injection gives about 20 times the exposure of a 10 mcg spray, erratic absorption with nasal mucosa changes.
- NABP. USP Compounding Chapters: Understanding the Latest Revisions, webinar handout, September 14, 2023: USP 795 Table 4, 14 days refrigerated for nonpreserved and 35 days for preserved aqueous preparations, sprays defined as aqueous.
- Al Bakri W, Donovan MD, Cueto M, Wu Y, Orekie C, Yang Z. Overview of intranasally delivered peptides: key considerations for pharmaceutical development. Expert Opin Drug Deliv. 2018;15(10):991-1005: permeation enhancers and mucoadhesives improve intranasal peptide bioavailability.
- Ashmarin IP, Baglikova KE, Edeeva SE, et al. A comparative analysis of distribution of glyprolines administered by various routes. Bioorg Khim. 2008;34(4):464-70: in rats, the intranasal route delivered Selank to the brain better than the other routes tested.
Related tools
- Semax and Selank – the two peptides most often used as nasal sprays.
- Peptide reconstitution calculator – the vial-and-syringe version of this arithmetic.
- Peptide pen calculator – units or clicks on a reusable pen.
- Peptide storage and shelf life – how long a mixed peptide lasts and why.
- Vial longevity calculator – how long a vial lasts and what each dose costs.