Source comparison
The route comparison that actually matters
One rodent study directly compared routes and found something that should give pause to anyone assuming injection is simply “stronger”. Comparing intraperitoneal and intranasal Semax on learning and pain sensitivity in rats, the authors reported that intranasa
This comparison does not assign a generated winner or score.
- One rodent study directly compared routes and found something that should give pause to anyone assuming injection is simply “stronger”. Comparing intraperitoneal and intranasal Semax on learning and pain sensitivity in rats, the authors reported that intranasal Semax was more potent for learning improvement than intraperitoneal, while the analgesic effect present after intraperitoneal administration was absent after intranasal administration. They concluded that different mechanisms and brain structures underlie the two effects[4].
- The implication is not that one route is better. It is that the routes produce qualitatively different effect profiles, not merely different intensities of the same effect. An mg-for-mg conversion between nasal and injected Semax is therefore not merely unsupported — the one study that examined the question directly suggests the premise of such a conversion is wrong. And note the comparison was intranasal against intraperitoneal, not against subcutaneous. Even this study, the closest thing to a route comparison that exists, does not speak to the subQ question.
- Registered product uses it
- Yes — 0.1% and 1% nasal solutions[2][3]
- No
- Human dosing studies
- Yes — 12–18 mg/day, acute stroke[11]
- None identified. One healthy-volunteer imaging study reports “injection” without specifying the subtype[14]
- Preclinical mechanistic work
- Yes — BDNF induction, receptor binding, chronic behaviour[9][15]
- No subcutaneous preclinical work identified. The parenteral rodent work is intraperitoneal[5], a laboratory route with no human equivalent
- Direct route comparison
- More potent for learning than the compared parenteral route[4]
- No subcutaneous comparison exists. The one direct comparison used intraperitoneal: the analgesic effect seen after IP was absent intranasally, indicating different effect profiles rather than different strengths[4]. IP is not a proxy for subQ
- Evidence tier
- Registered-product precedent + preclinical
- Extrapolation only — no tier applies
- For general anatomical background on parenteral peptide administration, see our guide on injection sites used in peptide research protocols — with the caveat that its applicability to Semax specifically is exactly what the table above puts in question.