it depends on how much prenisone / prednisolone you take. If you take massive pharmacological doses you will suppress your adrenals and need to take it for the rest of your life, with all the attendant side effects. If you take physiological doses, ie, no more than adrenal glands would produce themselves ona calm day (15-25 mg - the equivalent of 4-6 mg Pred) then there is little risk of adrenal suppression. Here is a medical study that shows this:

STUDY ON HPA AXIS AND LOW DOSE PREDNISONE
>
>
>
> Am J Med. 1993 Sep;95(3):258-64.
>
>
> Recovery of the hypothalamic-pituitary-adrenal (HPA) axis in
> patients with
> rheumatic diseases receiving low-dose prednisone.
>
> LaRochelle GE Jr, LaRochelle AG, Ratner RE, Borenstein DG.
>
> Division of Rheumatology, George Washington University Medical
> Center,
> Washington, D.C. 20037.
>
> PURPOSE: To assess the status of the hypothalamic-pituitary-adrenal
> (HPA)
> axis in cortico-steroid-treated patients whose prednisone dose had
> been
> tapered to physiologic doses. PATIENTS AND METHODS: The design of
> the study
> was a retrospective chart review of 50 consecutive patients
> receiving 10 mg
> or less of prednisone daily at a university teaching hospital
> rheumatology
> clinic. Patients were given a rapid adrenocorticotropic hormone
> stimulation
> test, with cortisol levels obtained at baseline and after intravenous
> administration of cosyntropin. Charts were reviewed for duration of
> therapy,
> highest, current, and total cumulative steroid dose, and average
> daily
> steroid dose in each month of the preceding 2 years. RESULTS: Current
> steroid dose was the only significant indicator of HPA axis function.
> Patients receiving less than 5 mg of prednisone daily had a normal
> HPA axis
> response, whereas those receiving 5 mg or more had widely varied
> responses.
> Neither the total, the highest prednisone dose, nor the duration of
> therapy
> was a significant indicator of HPA axis recovery. CONCLUSIONS:
> Spontaneous
> recovery of the HPA axis is usual for patients who are taking
> prednisone at
> daily doses of 5 mg or less. Return of normal HPA axis function can
> be
> achieved without alternate-day therapy in patients whose disease
> allows
> tapering to daily prednisone doses of 5 mg or less.
>
> Publication Types:
> a.. Review
> b.. Review, Tutorial
>
> PMID: 8368224 [PubMed - indexed for MEDLINE]
>

So it really does depend on the dose. Most of us taking cortisol to help our adrenals are taking no more than 20-25mg a day, which is merely replacing what our adrenals can't produce, shouldn't be expected to suppress them, and shouldn't have the side-effects asssociated with the massive doses of steroids prescribed by ignorant doctors.

Best
Nicola