TRH Thyrotropin (Protirelin)

Key points

• TRH (thyrotropin releasing hormone), as the medicine protirelin, is a short peptide that prompts the pituitary to release thyroid stimulating hormone.
• Its main medical role has been in diagnostic tests of thyroid and pituitary function.
• It is not a general treatment for thyroid problems, which have their own licensed medicines.
• It is sold online for research use, outside any medical supervision.

Quick facts

What it is

Thyrotropin releasing hormone (protirelin)

Used for

Diagnostic tests of thyroid and pituitary

UK status

Not a general treatment; sold online for research use

Human evidence

Established as a diagnostic agent only

How it works

TRH is released from the brain and tells the pituitary to make thyroid stimulating hormone, which in turn drives the thyroid gland. In a diagnostic test, giving TRH and measuring the response shows how the pituitary and thyroid are working. It has also been studied for effects on alertness and the nervous system, which are not established uses.

What the evidence shows

The established use of TRH is as a diagnostic agent, given under supervision. Other suggested uses, such as effects on mood or alertness, are not supported by the kind of trials needed to make them treatments.

What it does not settle

• There is little evidence for TRH as a treatment rather than a diagnostic agent.
• Suggested effects on alertness or mood are not established.
• There is no basis for self directed use.

Side effects

Common

• During a supervised test, brief flushing, a feeling of needing to pass urine, or a strange taste can occur.

Less common but serious

• Changes in blood pressure can occur, which is one reason it is given under supervision.
• Because there is no licensed product to buy, the dose, purity and contents of material sold online cannot be verified.

Report any suspected side effect through the MHRA Yellow Card scheme.

UK legal status and access

TRH, as protirelin, has mainly been used as a diagnostic agent under medical supervision, not as a treatment you would use yourself. Thyroid conditions are diagnosed with blood tests and treated with licensed medicines. Material sold online for research use is unverified.

Common questions