Approved, discontinuedHypothalamic tripeptide hormoneThyroid diagnostics
TRH (protirelin)
Protirelin (TRH) is the three-amino-acid hypothalamic hormone that stimulates TSH release; it was used as a diagnostic agent.
What is TRH?
Protirelin (TRH) is the three-amino-acid hypothalamic hormone that stimulates TSH release; it was used as a diagnostic agent. TRH (protirelin) was approved by the FDA, but the branded product has been discontinued; "research use only" vials sold online are not an approved drug.
Protirelin is a tripeptide composed of L-pyroglutamyl, L-histidyl and L-prolinamide residues joined in sequence. It has a role as a human metabolite. It is a peptide hormone and a tripeptide.
Key takeaways
- TRH (protirelin) was approved by the FDA, but the branded product has been discontinued; "research use only" vials sold online are not an approved drug.
- PubMed indexes 121 papers on TRH (17 tagged as clinical trials) as of October 19, 2026.
- ClinicalTrials.gov lists 15 registered studies using TRH.
- 2 vendors in our directory listed TRH in their public catalog on October 19, 2026.
Structure
Regulatory & access status
TRH (protirelin) was approved by the FDA, but the branded product has been discontinued; "research use only" vials sold online are not an approved drug.
Sellers that market unapproved peptides for human use can receive FDA warning letters; our vendor directory links any letter we found on fda.gov.
How much research exists on TRH (protirelin)?
PubMed indexes 121 papers mentioning TRH (protirelin) in the title or abstract, 10 of them from the last five years and 17 tagged as clinical trials (search run October 19, 2026; repeat the search).
Most relevant recent papers
- Protirelin (thyrotropin-releasing hormone) in amyotrophic lateral sclerosis. The role of androgens. — Arch Neurol, 1989 · review
- [Treatment for Spinocerebellar Degeneration]. — Brain Nerve, 2023
- Propranolol-induced hyperthyroxinemia. — Arch Intern Med, 1983
- Dose-response studies with protirelin. — Arch Gen Psychiatry, 1994
- Protirelin (TRH): a potent neuromodulator with therapeutic potential. — Arch Intern Med, 1984
- Diagnostic dosages of protirelin (TRH) elevate BP by noncatecholamine mechanisms. — Arch Intern Med, 1984
Registered clinical studies
ClinicalTrials.gov lists 15 studies with TRH (protirelin) as an intervention (see all). Most recent:
- A Long-Term Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD) — NCT01970124 · Phase 3 · completed
- An Extension Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD) — NCT01970111 · Phase 3 · completed
- A 24-week Open-label Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD) — NCT01970137 · Phase 3 · completed
- Study of Thyrotropin-Releasing Hormone in Normal Volunteers and in Patients With Thyroid or Pituitary Abnormalities — NCT00054756 · Phase 2 · completed · started 2003-02-07
- Thyroid and Glucose and Energy Metabolism — NCT00106119 · Phase 2 · completed · started 2005-03
What the evidence does not show
- Paper counts measure research attention, not whether TRH works or is safe.
- No FDA review of any "research use only" product's identity, purity, sterility or dose.
Research suppliers that list TRH
2 vendors in our directory listed a product matching TRH in their public catalog on October 19, 2026. Listed alphabetically; a listing is not an endorsement. Research use only.
Prices per mg, where we could verify them, are on our price comparison.
TRH reconstitution math
Lab arithmetic only, not dosing guidance: use the peptide calculator to turn a vial size and diluent volume into a concentration.
TRH FAQ
Is TRH FDA-approved?
TRH (protirelin) was approved by the FDA, but the branded product has been discontinued; "research use only" vials sold online are not an approved drug.
Is TRH safe?
Safety data come from the published studies listed on this page; read them in full. Products sold as "research use only" have no FDA review of their purity, sterility or dose.
How much research is there on TRH?
PubMed indexes 121 papers on TRH (17 tagged as clinical trials) as of October 19, 2026.
Who sells TRH?
Biotech Peptides, Core Peptides listed it on their public catalogs when we checked; a listing is not an endorsement.
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