High-pitched male voice

I'm 30, male, and have a high-pitched voice. I spoke with you briefly and you suggested my voice was within the normal pitch range. However, on the phone I am often mistaken for female, among other comments, and I would strongly like to lower it.

I have used speaking and singing coaches.

I am considering hormone testing.
Suppose my testosterone were (1) normal or that it were (2) low: At my age, would testosterone supplementation have any effect on my voice?