Peptide Nasal Spray: Semax, Selank and Oxytocin Evidence
A peptide nasal spray delivers a peptide drug through the lining of the nose, and three have FDA labels on DailyMed: calcitonin salmon, desmopressin (Stimate) and nafarelin (Synarel). Absorption is low: the Stimate label reports 3.3 to 4.1 percent. For the research sprays people often search for, semax and selank, we found no FDA label and no human absorption data. Nasal oxytocin has been studied for anxiety, and a 2025 review calls that evidence mixed. Uptake is small. A review says less than 1% of a peptide or protein drug normally gets in through the nose.
Sources: Ozsoy Y et al. Nasal delivery of high molecular weight drugs. Molecules, 23 September 2009. PMID 19783956. Supports: nasal bioavailability of peptide and protein drugs normally less than 1%; STIMATE (desmopressin acetate) nasal spray FDA label, DailyMed set ID f5ada39c-20ed-4500-9dce-1e4ab642a358 (version dated 22 July 2026, retrieved October 2026). Supports: use in hemophilia A; absolute bioavailability 3.3 to 4.1 percent; nasal conditions that may change absorption
Short answer
- Which peptide nasal sprays are approved?
- We found FDA labels for three: calcitonin salmon, desmopressin (Stimate) and nafarelin (Synarel). Each is for a narrow medical use.
- How much gets in?
- Often a few percent or less. The calcitonin label says the spray gives about 3% of what the shot gives.
- What about semax and selank sprays?
- We found no FDA label and no human absorption data. The FDA warns that pharmacy-made semax may cause immune reactions. It says it lacks safety facts on selank acetate in people.
Sources: Calcitonin Salmon Nasal Solution FDA prescribing information, DailyMed set ID a6eaedb3-5c96-4859-be43-a48c9c818bc7 (version dated 29 June 2026, retrieved October 2026). Sections used: Indications and Usage; Clinical Pharmacology (bioavailability about 3% of the injection); STIMATE (desmopressin acetate) nasal spray FDA label, DailyMed set ID f5ada39c-20ed-4500-9dce-1e4ab642a358 (version dated 22 July 2026, retrieved October 2026). Supports: use in hemophilia A; absolute bioavailability 3.3 to 4.1 percent; nasal conditions that may change absorption; SYNAREL (nafarelin acetate) nasal solution FDA prescribing information, DailyMed set ID d0aa57cb-d2f4-46d7-af43-7c8b06aa81a6 (version dated 5 March 2026, retrieved October 2026). Sections used: Description (decapeptide); Clinical Pharmacology (peak serum levels at 10 to 40 minutes); US FDA web page, Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (page dated 22 April 2026, retrieved October 2026). Supports: the GHRP-2 (injectable and nasal), semax and selank acetate entries
Do Peptides Work in a Nasal Spray?
Peptides do work in a nasal spray for some approved drugs, but only a small share is absorbed: a 2009 review in Molecules says peptide and protein drugs are normally under 1% by the nose. The nose is a real route for peptides, with real limits.
The nose has good points as a route. A 2002 review says it is one of the most permeable places to give a drug. Permeable means things pass through easily. The review also calls it highly vascularized, meaning rich in blood vessels. That allows fast absorption. A 2025 review calls nasal peptides a promising approach. They can get a drug into the body. They can also send it from the nose toward the brain.
The problem is how peptides are built. A 2009 review says they are hydrophilic, meaning water-loving. Because of that, their nasal bioavailability is normally less than 1%. Bioavailability is the share of a dose that reaches the blood. For how this compares with other routes, see oral vs injectable peptides.
Sources: Arora P et al. Permeability issues in nasal drug delivery. Drug Discovery Today, 15 September 2002. PMID 12546871. Supports: the nose as a permeable, highly vascularized site with rapid absorption; Jülke EM et al. Peptide therapeutics: current status and future opportunity with focus on nose-to-brain delivery. Peptides, June 2025. PMID 40222598. Supports: nasal peptides for body and brain delivery; nose to brain use in the clinic, mechanisms poorly understood; Ozsoy Y et al. Nasal delivery of high molecular weight drugs. Molecules, 23 September 2009. PMID 19783956. Supports: nasal bioavailability of peptide and protein drugs normally less than 1%
How Much of a Nasal Peptide Gets Absorbed?
Nasal peptide absorption is low: the calcitonin salmon label reports about 3% of the injectable form, and the Stimate label reports 3.3 to 4.1 percent. For research sprays such as semax and selank, we found no human absorption data at all.
| Product | Absorption figure | Source |
|---|---|---|
| Peptide and protein drugs in general | Normally less than 1% | 2009 review of nasal delivery |
| Calcitonin salmon nasal solution | About 3% of the injectable form | FDA label, healthy subjects |
| Stimate (desmopressin) nasal spray | 3.3 to 4.1 percent absolute bioavailability | FDA label |
| Synarel (nafarelin) nasal solution | Rapid absorption, peak blood levels at 10 to 40 minutes | FDA label |
| Semax, selank and other research sprays | No human absorption data found | PubMed search, October 2026 |
The state of the nose matters too. The Stimate label names swelling, congestion, scarring or injury in the nose. It says these may change how well the spray is absorbed.
Sources: Ozsoy Y et al. Nasal delivery of high molecular weight drugs. Molecules, 23 September 2009. PMID 19783956. Supports: nasal bioavailability of peptide and protein drugs normally less than 1%; Calcitonin Salmon Nasal Solution FDA prescribing information, DailyMed set ID a6eaedb3-5c96-4859-be43-a48c9c818bc7 (version dated 29 June 2026, retrieved October 2026). Sections used: Indications and Usage; Clinical Pharmacology (bioavailability about 3% of the injection); STIMATE (desmopressin acetate) nasal spray FDA label, DailyMed set ID f5ada39c-20ed-4500-9dce-1e4ab642a358 (version dated 22 July 2026, retrieved October 2026). Supports: use in hemophilia A; absolute bioavailability 3.3 to 4.1 percent; nasal conditions that may change absorption; SYNAREL (nafarelin acetate) nasal solution FDA prescribing information, DailyMed set ID d0aa57cb-d2f4-46d7-af43-7c8b06aa81a6 (version dated 5 March 2026, retrieved October 2026). Sections used: Description (decapeptide); Clinical Pharmacology (peak serum levels at 10 to 40 minutes)
Nasal Sprays With an FDA Label
Three peptide-type nasal sprays have FDA labels on DailyMed: calcitonin salmon nasal solution, Stimate (desmopressin) and Synarel (nafarelin), each for a narrow medical use.
- Calcitonin salmon nasal solution. Its label use is postmenopausal osteoporosis, or thin bones after menopause. It is for women more than 5 years past menopause. It is used when other treatments are not suitable.
- Stimate (desmopressin acetate). Its label calls it a vasopressin analog used for hemophilia A.
- Synarel (nafarelin acetate). Its label says the active part is a decapeptide. That is a peptide of ten amino acids. It is sprayed onto the lining of the nose. Nafarelin is absorbed fast. Blood levels peak between 10 and 40 minutes.
These labels show that a nasal peptide can be made to work as a medicine. They say nothing about research sprays, which have not gone through that review.
Sources: Calcitonin Salmon Nasal Solution FDA prescribing information, DailyMed set ID a6eaedb3-5c96-4859-be43-a48c9c818bc7 (version dated 29 June 2026, retrieved October 2026). Sections used: Indications and Usage; Clinical Pharmacology (bioavailability about 3% of the injection); STIMATE (desmopressin acetate) nasal spray FDA label, DailyMed set ID f5ada39c-20ed-4500-9dce-1e4ab642a358 (version dated 22 July 2026, retrieved October 2026). Supports: use in hemophilia A; absolute bioavailability 3.3 to 4.1 percent; nasal conditions that may change absorption; SYNAREL (nafarelin acetate) nasal solution FDA prescribing information, DailyMed set ID d0aa57cb-d2f4-46d7-af43-7c8b06aa81a6 (version dated 5 March 2026, retrieved October 2026). Sections used: Description (decapeptide); Clinical Pharmacology (peak serum levels at 10 to 40 minutes)
Can Nasal Peptides Reach the Brain?
Some nasal peptides may reach the brain: a 2025 review in Peptides (PMID 40222598) says nose to brain delivery is already used in clinics. But how it works is poorly understood.
"Poorly understood" matters here. It means nobody can say how much of a research spray reaches the brain. Nor can anyone say how steady that amount is.
Semax and Selank Nasal Sprays
Semax and selank nasal sprays have no FDA label we could find in openFDA, and no human data on how much is absorbed. The FDA's April 2026 compounding safety page lists both.
The FDA lists both on one page. It covers raw ingredients that may be risky when pharmacies mix drugs (compounding). It says pharmacy-made semax may cause immune reactions for some routes. The reasons are clumping (aggregation) and impurities. On selank acetate, it says it lacks key safety facts in people.
One small 2018 study gave semax by nose and then scanned the brain. The study reports:
Intranasal 1% semax (14 subjects) or placebo (10 subjects); resting state fMRI before, and 5 and 20 minutes after
Disclaimer: this is a study design from a paper. It is not label information and not a recommendation. Choices about any compound belong with a licensed clinician.
A brain scan study this size shows activity changes, not a health benefit. For the two peptides in more depth, see the semax profile, the selank profile and semax vs selank. The FDA also names a nasal route for GHRP-2. It says pharmacy-made GHRP-2 for shots or nasal use may cause immune reactions. See the GHRP-2 profile.
Sources: US FDA web page, Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (page dated 22 April 2026, retrieved October 2026). Supports: the GHRP-2 (injectable and nasal), semax and selank acetate entries; Lebedeva IS et al. Effects of Semax on the default mode network of the brain. Bulletin of Experimental Biology and Medicine, September 2018. PMID 30225715. Supports: study design, intranasal 1% semax (14 subjects) or placebo (10 subjects) with resting state fMRI
Oxytocin Nasal Spray
Oxytocin nasal spray has been studied for anxiety and stress, and a 2025 systematic review in BMC Pharmacology and Toxicology (PMID 41074229) says the evidence that it works is still mixed.
That review looked at brain scans (fMRI). It asked how nasal oxytocin changes the brain in anxiety and stress disorders. For what else is known about peptides and anxiety, see peptides for anxiety.
Is Flonase a Peptide Nasal Spray?
No. Flonase is a steroid spray, not a peptide: its Drug Facts label on DailyMed lists fluticasone propionate, a glucocorticoid, as the active ingredient. A glucocorticoid is a type of steroid. Its purpose is allergy relief.
The label says it eases hay fever and other nose and airway allergies for a time. The symptoms it lists are a stuffy nose, itchy nose, runny nose, itchy and watery eyes, and sneezing. openFDA lists it as an over-the-counter human drug product.
The Flonase Allergy Relief drug facts label lists:
Fluticasone propionate (glucocorticoid): 50 mcg in each spray
Disclaimer: this is label information, not a recommendation. Choices about any medicine belong with a licensed clinician or pharmacist.
This page describes labels and studies. It does not tell anyone to use a nasal spray, or how much. Research peptide sprays are not FDA-approved medicines.
Common Questions
Do peptides work in nasal spray?+
Some do, as approved medicines. FDA labels exist for nasal sprays of calcitonin salmon, desmopressin (Stimate) and nafarelin (Synarel). But uptake is low. A review says less than 1% of a peptide or protein drug normally gets in through the nose. For research sprays such as semax and selank, we found no human absorption data.
How much of a nasal peptide reaches the blood?+
Usually a small share. The calcitonin nasal label says about 3% of what the shot gives. The Stimate label says 3.3 to 4.1 percent. A review says peptide and protein drugs are normally under 1% by the nose.
Are semax and selank nasal sprays FDA approved?+
We found no FDA label for either. On the FDA site, they show up on a page of raw ingredients that may be risky when pharmacies mix drugs. The FDA says pharmacy-made semax may cause immune reactions. It says it lacks key safety facts on selank acetate in people.
Can peptides reach the brain through the nose?+
Researchers think some can. A 2025 review says nose to brain delivery is already used in clinics. But how it works is poorly understood.
Is Flonase a peptide nasal spray?+
No. Its label lists fluticasone propionate as the active ingredient. That is a glucocorticoid, a type of steroid. openFDA lists it as an over-the-counter human drug product. It is for hay fever and other allergy symptoms of the nose and airways.
Does a stuffy nose change how a nasal spray works?+
It can. The Stimate label names swelling, congestion, scarring or injury in the nose. It says these may change how well the spray is absorbed.
Sources: Ozsoy Y et al. Nasal delivery of high molecular weight drugs. Molecules, 23 September 2009. PMID 19783956. Supports: nasal bioavailability of peptide and protein drugs normally less than 1%; Calcitonin Salmon Nasal Solution FDA prescribing information, DailyMed set ID a6eaedb3-5c96-4859-be43-a48c9c818bc7 (version dated 29 June 2026, retrieved October 2026). Sections used: Indications and Usage; Clinical Pharmacology (bioavailability about 3% of the injection); STIMATE (desmopressin acetate) nasal spray FDA label, DailyMed set ID f5ada39c-20ed-4500-9dce-1e4ab642a358 (version dated 22 July 2026, retrieved October 2026). Supports: use in hemophilia A; absolute bioavailability 3.3 to 4.1 percent; nasal conditions that may change absorption; SYNAREL (nafarelin acetate) nasal solution FDA prescribing information, DailyMed set ID d0aa57cb-d2f4-46d7-af43-7c8b06aa81a6 (version dated 5 March 2026, retrieved October 2026). Sections used: Description (decapeptide); Clinical Pharmacology (peak serum levels at 10 to 40 minutes); US FDA web page, Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (page dated 22 April 2026, retrieved October 2026). Supports: the GHRP-2 (injectable and nasal), semax and selank acetate entries; Jülke EM et al. Peptide therapeutics: current status and future opportunity with focus on nose-to-brain delivery. Peptides, June 2025. PMID 40222598. Supports: nasal peptides for body and brain delivery; nose to brain use in the clinic, mechanisms poorly understood; Flonase Allergy Relief (fluticasone propionate) Drug Facts label, DailyMed set ID b6134ba0-b70a-4eac-9a82-cef64b242c1d (version dated 19 December 2024, retrieved October 2026); openFDA product type human OTC drug. Supports: active ingredient 50 mcg per spray, purpose and uses
Related reading
This guide is for educational purposes only and is not medical advice. It describes what FDA labels, published reviews and studies report about peptides given by nasal spray. It is not an endorsement or an instruction to use any compound. Semax and selank are not FDA-approved medicines. Talk to a qualified healthcare professional before making any decision about your health.