Some peptides can be taken as a nasal spray instead of an injection, some work nasally but not as well, and some do not work nasally at all. This article sorts the common ones into those three groups so you know which route to use.
Nasal delivery suits peptides with documented nose-to-brain transport and adequate mucosal absorption, but is inferior or ineffective for many others.
Peptides that work nasally
A nasal spray is a bottle with a pump that sends a fine mist into the nose. Some peptides are absorbed well through the lining of the nose, and a few can travel from the nose almost straight to the brain. For those peptides, a spray can work as well as, or better than, an injection.
The peptides with the strongest evidence for nasal use are:
- Semax – This was made as a nasal spray in Russia from the start. A lot of clinical research shows it moves directly from the nose to the brain.
- Selank – Also approved in Russia as a nasal spray. It reaches the brain quickly, and its calming and focus effects are reported to be stronger by nose than by injection.
- DSIP – Research shows the nasal route and injection work equally well at getting into the brain and increasing the slow brain waves linked to deep sleep.
- Oxytocin – Nasal versions are FDA-approved, and hundreds of clinical trials back up that they work.
- NAD+ – Studies show the nasal route gets more of it into the brain than an IV drip, and it avoids the very poor absorption seen when it is swallowed.
- GHK-Cu – Research indexed on PubMed shows the nasal route works for brain and memory benefits because of the direct nose-to-brain path.
- VIP – Research shows the nasal route gives higher brain levels than IV. It has been used in over 10,000 patients since 2008.
What this means for you: if you want one of these peptides mainly for brain, mood, sleep, or focus effects, a nasal spray is a sensible choice. You do not need to inject them to get the benefit. To make a spray, the peptide is dissolved in sterile saline and put in a clean nasal spray bottle. The exact amounts, and how many sprays to use, are set out on each compound's own page rather than here.
Intranasal delivery exploits two pathways: absorption across the respiratory mucosa into systemic circulation, and direct transport along the olfactory and trigeminal nerves into the CNS, bypassing the blood-brain barrier. Peptides with small size, reasonable stability in the nasal cavity, and a primary CNS target are the best candidates. The following have direct evidence supporting the route:
- Semax – Developed in Russia as a nasal formulation from the outset. Extensive clinical research confirms direct nose-to-brain delivery, consistent with its melanocortin-derived neurotrophic (BDNF-modulating) action.
- Selank – Approved in Russia as a nasal spray. Rapid CNS absorption is documented, and its anxiolytic and nootropic effects are reported to be greater by the nasal route than by injection.
- DSIP – Research confirms nasal and injected administration are equally effective at crossing the blood-brain barrier and increasing delta-wave activity on EEG.
- Oxytocin – FDA-approved nasal spray formulations exist, with hundreds of clinical trials confirming effectiveness, making it the best-characterised nasal peptide in this list.
- NAD+ – Published studies show intranasal administration produces higher brain concentrations than IV infusion and bypasses the negligible oral bioavailability of the molecule.
- GHK-Cu – PubMed-indexed research supports intranasal delivery for cognitive endpoints via the direct nose-to-brain pathway, distinct from its topical and subcutaneous use for skin and tissue remodelling.
- VIP – Research shows nasal administration produces higher brain concentrations than IV. It has been used clinically in 10,000+ patients since 2008, largely in inflammatory and neuroimmune contexts.
In practice, for these compounds the nasal route is not a compromise: where the target is central, olfactory transport can deliver more drug to the brain per unit dose than parenteral routes, and it avoids first-pass metabolism entirely. Preparation follows the same principle as reconstitution for injection, with the lyophilised peptide dissolved in sterile saline and transferred to a metered nasal pump; concentration is chosen so that a known number of sprays delivers the intended dose. Compound-specific concentrations and per-spray doses are carried on the individual compound pages.
Works nasally, injection preferred
Some peptides do get absorbed through the nose, but not reliably or not very much. For these, an injection under the skin gives a more predictable result, and a nasal spray is a second-best option that usually needs a bigger dose.
- PT-141 – Works as a spray, but the amount absorbed varies a lot from person to person. That is why the FDA approved the injected version rather than a nasal one. If you use it nasally, expect results to be less consistent.
- Epithalon – Works nasally, but you need 2-3 times the injected dose to get a similar effect, so it uses up the vial much faster.
- Melanotan 2 – Only 30-40% of the dose gets in through the nose compared with an injection, so higher doses are needed and the tanning effect is harder to judge.
- BPC-157 – There is very little research on nasal use. Injection under the skin is still the standard for healing tissue, so a spray is a gamble for that purpose.
- TB-500 – Can work nasally, but injection is preferred when the goal is repairing muscle, tendon, or other tissue. The nasal route makes more sense if the aim is brain-related effects.
What this means for you: if the goal is healing a specific injury, tanning, or a reliable response, use the injection. A nasal spray for these peptides is mainly useful if you cannot or will not inject, and you should expect to need more product and get a weaker or less steady effect. Any dose figures on the individual compound pages refer to the standard injected protocol unless they say otherwise.
This group shows measurable nasal absorption but with pharmacokinetic disadvantages, mainly low or variable bioavailability, that make subcutaneous injection the preferred route for the usual indications.
- PT-141 (bremelanotide) – Nasal delivery is effective at the melanocortin MC4 receptor target, and nasal formulations were studied, but the FDA chose to approve the subcutaneous form because of variable inter-individual nasal absorption. Nasal use trades convenience for an unpredictable dose-response.
- Epithalon – Effective by the nasal route but requires 2-3x the injectable dose for comparable results, reflecting incomplete mucosal absorption of the tetrapeptide.
- Melanotan 2 – Nasal bioavailability is only 30-40% relative to injection, so higher doses are required. Given its dose-dependent side-effect profile at MC1/MC4 receptors, the variability is a practical problem.
- BPC-157 – Very limited nasal research exists. Subcutaneous administration remains the gold standard for tissue repair, where local and systemic exposure near the injury is the relevant endpoint. Nasal delivery has no established evidence base for that use.
- TB-500 – Can work nasally, but injection is preferred for tissue repair, where systemic thymosin beta-4 fragment exposure and actin-sequestering activity at the site of injury matter. Nasal administration is better suited to neurological endpoints, where nose-to-brain transport is an advantage rather than a limitation.
The common thread is that the nasal route is not inert for these compounds, but the therapeutic target is either peripheral (tissue repair, melanogenesis) or the absorption is too inconsistent to titrate reliably. Where a compound's effect is central, as with TB-500 for neurological use, the nasal route becomes defensible. In practice, users who choose the nasal route for this group should expect to need higher total doses and to see a less consistent response than with the standard subcutaneous protocols carried on the compound pages.
Not effective nasally
Some peptides simply do not work as a nasal spray. Their molecules are too big or the wrong shape to pass through the lining of the nose in useful amounts, or the effect they are meant to produce does not happen when they are given that way. Turning these into a spray wastes the peptide and gives no benefit.
- GLP-1 weight-loss compounds – This includes Retatrutide, Semaglutide, and Tirzepatide. Their molecular structure is not suited to being absorbed through the nose. They must be injected under the skin.
- Growth hormone releasing peptides – This includes CJC-1295 with Ipamorelin, Tesamorelin, and Sermorelin. Used nasally they do not trigger the release of growth hormone. They must be injected under the skin.
What this means for you: if you are using any of these for weight loss, blood sugar, muscle, recovery, or sleep, do not try to make a nasal spray of them. There is no version of the dose that makes it work. Stick to the injected protocol on the compound's own page.
A simple way to remember the whole picture: peptides that act mainly on the brain often work well by nose; peptides that need to reach the whole body, or that are larger molecules, usually need an injection. If a peptide is not listed in any of the three groups in this article, treat injection as the default unless there is clear evidence for nasal use.
Two important classes have no meaningful nasal efficacy and should not be formulated as sprays.
- GLP-1 receptor agonists and related incretin mimetics – Retatrutide, Semaglutide, and Tirzepatide have a molecular structure not suited for nasal absorption. These are large, often acylated or albumin-binding peptides engineered for prolonged systemic half-life after subcutaneous depot absorption; the nasal mucosa does not deliver them in pharmacologically relevant quantities. Subcutaneous administration is mandatory.
- GH secretagogues – CJC-1295/Ipamorelin, Tesamorelin, and Sermorelin are not effective nasally for GH release and must be given subcutaneously. The GHRH analogues (CJC-1295, Tesamorelin, Sermorelin) and the ghrelin-receptor agonist Ipamorelin act on pituitary somatotrophs via systemic circulation, and the GH pulse that defines their effect is not reproduced by nasal dosing.
The pattern across this article is consistent with the underlying pharmacology. Nasal delivery favours small, stable peptides whose primary target is the CNS, where olfactory and trigeminal transport can outperform parenteral routes on a per-dose basis. It performs poorly for compounds requiring sustained systemic exposure, peripheral tissue concentration, or reliable pulsatile endocrine signalling, and it fails outright for the larger metabolic and GH-axis peptides listed here. For any compound not explicitly documented as nasally effective, the default assumption should be that subcutaneous injection is the validated route, and the standard protocols on the individual compound pages should be followed rather than improvised nasal conversions.
This article was written from additional reference material. It is educational and not medical advice.