Not yet available, we are working hard on this format.
View the Semax penThe setup
Why these two routes exist at all
Swallowed peptides meet the same enzymes that digest dietary protein, which is why the oral route is closed to almost everything in this catalogue. Any viable route has to go around the gut.
Injection goes around it completely: material enters subcutaneous tissue and reaches circulation with well-understood, broadly compound-independent efficiency. It is the default in research for that reason, the delivery variable is essentially removed.
The nasal mucosa offers a second bypass. It is permeable enough for small molecules to cross, needle-free, and fast to administer. But its permeability falls sharply as molecular size rises, which turns chain length into a gatekeeper.
Posed as nasal spray vs injection, the question sounds like one of taste, and for most of this catalogue it is not a question at all: only a handful of sequences are short enough for the first option to exist. Where both are genuinely available, semax and selank being the clearest cases, the decision is about what a protocol needs to hold constant, not about which route feels more agreeable. The semax page sets out how one compound came to be studied in both.
Side by side
Route against route
The comparison as the chemistry sees it.
| Nasal spray | Subcutaneous injection | |
|---|---|---|
| Digestive bypass | Yes, via the nasal mucosa | Yes, complete |
| Works for which peptides | Short sequences; viability drops with size | Any compound in this catalogue |
| Delivery efficiency | Lower and more variable between individuals | Higher and more consistent |
| Dose precision | Metered pump; per-spray consistency is good, absorption is the variable | Syringe or pen; both measured and absorbed predictably |
| Handling | No sharps, no reconstitution in our formats | Needles, technique, disposal |
| Research caveat | Whether intranasal delivery reaches the brain is a contested question | Few route-specific controversies |
| In this catalogue | Short compounds only: semax, selank, DSIP, NAD+, PT-141 blend | Everything else, as pens and vials |
Our spray list is short by chemistry, not by choice: only sequences short enough for credible mucosal absorption are offered in the format.
The honest caveats
What each route cannot promise
The spray’s weakness is quantitative. Less material crosses, and how much varies with mucosal condition, a blocked nose is a changed experiment. Claims that intranasal peptides reach the brain directly along nasal nerves exist in the literature and remain genuinely contested; we sell sprays while saying so, because the alternative is selling them while not saying so.
Injection’s weakness is practical rather than pharmacological: sharps, technique, and the handling chain from reconstitution to disposal. Every step is well understood, which is different from every step being effortless.
What neither route changes is the compound or the evidence behind it. A weak literature does not improve because the delivery is convenient, and a strong one does not weaken because needles are involved.
There is a reason the contested claim attaches to this route rather than the other one. Whether material can travel from the nasal cavity along olfactory and trigeminal pathways instead of through the bloodstream has been studied for decades without a settled answer, and the nose-to-brain delivery literature is where that argument is actually conducted. Reading it is more useful than reading anyone’s marketing about it, in either direction.
For a comparison to mean anything, each route has to be documented in its own terms. A spray record is a count of actuations from a bottle whose concentration was fixed at filling; an injectable record is a volume drawn at a concentration you either set or inherited from a cartridge. The two are not convertible by arithmetic, which is why the handling page for pens and the labelling of a spray bottle ask for different notes. Where both formats of one compound are on the shelf, the cognition area is where most of those side-by-side pairs happen to sit.
Our readingChain length picks the shortlist; the protocol picks from it. Long peptides have one route, and it involves a needle. Short peptides have two, and the choice trades delivery certainty against handling simplicity. Preference only ever operates inside the space the molecule allows.
From the catalogue
Both routes, where both are viable
Semax and selank appear in each format; the choice between them is exactly this page.
Go deeper
Around the routes
The format pages and their practical background.
Questions
About the routes
The recurring questions when both formats exist.