A Synacthen stimulation test assesses the cortisol response to Synacthen, which is synthetic ACTH. In general, the test involves a baseline blood sample, an injection and a second blood sample about 30 minutes later.
The appointment usually takes 45–60 minutes. Please enquire so the clinic can confirm the appointment requirements before arranging your test.
Written by Mr Stephen Lingam. Reviewed by Dr Mohammad Bakhtiar (GMC 4694470) on 20/08/2026.
It assesses how cortisol responds to Synacthen, which is synthetic ACTH.
In general, a baseline blood sample is taken, Synacthen is given by injection, and a second sample is taken about 30 minutes later. The appointment usually takes 45–60 minutes.
Laboratory results are usually available in 1 day.
Please enquire so the clinic can confirm the appointment requirements and arrange the test with you.