Brief Answer:
Hormone tests

Detailed Answer:
Sorry to learn about your exercise intolerance.

I wonder why you are on androcur. It has very limited use ir it is approved only for advanced prostate cancer for example.

It can cause fatigue and lassitude. So it is possible what you are experiencing as exercise intolerance is a manifestation of this effect.

Moreover it opposes the effect of male hormones at the level of human cells in the body. It can also suppress the adrenal gland function. So testing for that is important because that can cause fatigue too.
When I see someone like you in my practice, I typically order the following blood tests in addition to a detailed physical examination:

CBC (Complete Blood Count, also known as Hemogram; includes Hemoglobin, WBC and Platelet counts)
Electrolytes (Sodium and Potassium in particular)
HbA1c (Glycosylated Hemoglobin = your last 3 months' glucose average). Also known by other names such as GlycoHemoglobin or Glycated Hemoglobin or A1c
Liver function tests (SGOT , SGPT, Albumin, Bilirubin, Alkaline Phosphatase)
Kidney function tests (BUN, Creatinine) 12 hour Fasting Lipid profile
Urine albumin to Creatinine Ratio (early sign of diabetes affecting the kidney)
25 hydroxy Vitamin D levels (ideal range 40 to 60 ng/ml = 100 to 150 nmol/liter)
8 am serum Cortisol (test for adrenal function)
Correct diagnosis and treatment requires the opportunity to examine the patient so you must see an endocrinologist in-person.

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Brief Answer:
Follow up

Detailed Answer:
I see.

Well I have provided you with the reply above that it can cause tiredness. So this could possibly be the cause of your exercise intolerance. The only way to be reasonably sure is to stop it for a couple weeks and see if the symptoms improve.
And then if you were to restart androcur, and the same symptoms re-occur then it is very likely due to androcur.

Although I would not prescribe androcur to any male for the purpose you are taking.

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Brief Answer:
Best wishes

Detailed Answer:
for good health

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