Intranasal Administration
Non-injection delivery via nasal mucosa — rapid brain and systemic uptake without needles.
Overview
Intranasal administration deposits a peptide solution onto the highly vascularised nasal mucosa. The nasal epithelium provides direct access to the systemic circulation and, uniquely, a pathway along the olfactory nerve to the central nervous system — bypassing the blood-brain barrier. This makes intranasal an especially relevant route for neuropeptides. Bioavailability is lower than injection but onset is rapid, and the needle-free format makes it practical for repeated daily dosing.
Equipment Required
Administration Sites
Administration Protocol
Reconstitute the peptide in sterile saline or bacteriostatic water per the research protocol. Intranasal concentrations are typically higher than injection concentrations to compensate for lower bioavailability.
Gently blow the nose 5–10 minutes before administration to clear mucus that could impede absorption. Do not blow immediately before — this may irritate the mucosa.
Draw the solution into the syringe, attach the nasal atomizer tip, and prime with a small test spray to clear the device of air.
Tilt the head slightly forward and down (sniffing position). This directs the spray toward the upper nasal cavity where olfactory nerves are densest — critical for CNS-targeted peptides.
Insert the atomizer tip just inside the nostril (5–7 mm), angle slightly outward toward the ear (away from the septum). Depress the plunger in one firm, quick motion while inhaling gently through the nose.
Keep the head in the same position for 30–60 seconds. Avoid sniffing forcefully, blowing the nose, or swallowing repeatedly — these actions move the solution away from the absorption surface.
If splitting dose across both nostrils, wait 1–2 minutes before administering to the second nostril. Log which nostril was used last to rotate systematically.
✅ Best Practices
- Lower the peptide concentration if experiencing nasal irritation — high concentrations in small volumes can cause burning.
- Administration first thing in the morning on an empty stomach may improve absorption for some neuropeptides.
- Store reconstituted intranasal solutions refrigerated and use within 30 days.
- A mild tingling or cooling sensation after application is normal and indicates mucosal contact.
⚠️ Common Mistakes
- Spraying directly onto the nasal septum — causes irritation and poor absorption.
- Sniffing hard immediately after — pushes solution into the throat where it is swallowed rather than absorbed.
- Using too low a concentration — requires excessive volume per dose that cannot be retained in the nasal cavity.
- Forgetting to prime the atomizer — first actuation delivers little to no solution.
Commonly Used With
Frequently Asked Questions
Why is intranasal dose typically higher than injection?
Bioavailability via the nasal route is typically 30–60% of an equivalent injected dose for most peptides. Protocols compensate by increasing the administered amount to achieve comparable systemic concentrations.
Can all peptides be administered intranasally?
No. Intranasal administration is most effective for smaller peptides with known nasal mucosa permeability. Semax and Selank are the most established intranasal research peptides. Larger molecules (e.g. TB-500 at 44 amino acids) have poor nasal absorption.
Is a standard syringe without an atomizer sufficient?
A plain syringe produces droplets rather than an atomised mist, resulting in poor mucosal distribution and uneven absorption. A mucosal atomisation device (MAD) produces fine particles of 30–100 microns that coat the mucosa effectively and is strongly preferred.
How quickly does intranasal onset occur compared to injection?
Onset is typically faster than subcutaneous injection (5–15 min vs 15–30 min) due to the rich blood supply and direct vascular access of the nasal mucosa, though peak plasma levels are lower.
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