Quick summary
Substance P is an 11-amino acid tachykinin neuropeptide central to pain signaling, neurogenic inflammation, and mood regulation. NK1 receptor antagonists derived from Substance P research (aprepitant, netupitant) are FDA-approved antiemetics, validating the SP-NK1R axis as a therapeutic target.
Overview
Substance P is an 11-amino acid neuropeptide belonging to the tachykinin family, with the sequence Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2. It functions as both a neurotransmitter and neuromodulator in the central and peripheral nervous systems, playing a key role in pain signaling, neurogenic inflammation, and mood regulation. It was among the first neuropeptides discovered and has been studied for over 90 years.
Mechanism of action
Substance P acts primarily through the NK1 (neurokinin-1) receptor, a Gq-coupled GPCR, with lower affinity for NK2 and NK3. Binding to NK1R activates phospholipase C, raises intracellular calcium, and activates PKC, promoting neuronal excitation and synaptic facilitation. In primary afferent nociceptors, SP co-localizes with glutamate and CGRP, facilitating pain transmission to the dorsal horn. Peripheral SP release from afferent nerve endings triggers mast cell degranulation, vasodilation, plasma extravasation, and immune cell recruitment — the hallmarks of neurogenic inflammation.
Dosing protocols
| Purpose | Route | Dosage | Frequency | Notes |
|---|---|---|---|---|
| nociception research (animal) | intravenous | 1–10 nmol/kg | per study protocol |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
Research summary
NK1 receptor antagonists (aprepitant, netupitant) have been developed and are FDA-approved as antiemetics in chemotherapy-induced nausea/vomiting, validating the SP-NK1R axis as a therapeutic target. Research into NK1 antagonists for depression, PTSD, and chronic pain continues. Elevated SP levels are associated with fibromyalgia, IBS, and inflammatory arthritis. SP also plays a role in wound healing and angiogenesis, creating therapeutic interest beyond pain.[1][2][3][4][5]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with Substance P for synergistic effects.
Legal status
Substance P is a research chemical used in preclinical pain and inflammation studies. Not approved for human administration. NK1 receptor antagonists derived from this research (e.g., aprepitant) are FDA-approved drugs.
Sourcing & access
Research compound
Substance P is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).
Frequently asked questions
Substance P is an 11-amino acid neuropeptide belonging to the tachykinin family that functions as both a neurotransmitter and neuromodulator. It plays key roles in pain signaling, neurogenic inflammation, and mood regulation in the central and peripheral nervous systems.
Substance P acts primarily through the NK1 (neurokinin-1) receptor, a Gq-coupled GPCR. Binding activates phospholipase C, raises intracellular calcium, and promotes neuronal excitation. Peripheral SP release triggers mast cell degranulation, vasodilation, and immune cell recruitment, the hallmarks of neurogenic inflammation.
Substance P is a research compound not approved for human administration. In research settings, intravenous doses can cause vasodilation, flushing, bronchoconstriction at high doses, and pain at injection sites. NK1 receptor antagonists targeting this pathway have well-established clinical safety profiles.
NK1 receptor antagonists such as aprepitant and netupitant are FDA-approved for chemotherapy-induced nausea and vomiting. Research into NK1 antagonists for depression, PTSD, and chronic pain continues, with elevated Substance P levels observed in fibromyalgia, IBS, and inflammatory arthritis.
Research references
- Biochemistry, Substance PReview
- Substance P, a Neuropeptide, Promotes Wound Healing via Neurokinin-1 ReceptorPubMed
- Inflammation and Organ Injury the Role of Substance P and Its ReceptorsReview
- The Role of Substance P Within Traumatic Brain Injury and Implications for TherapyPubMed
- Modulating the tachykinin: Role of substance P and neurokinin receptor expression in ocular surface disordersPubMed