DHT is not only produced from the conversion from gonadal testosterone, but also in the adrenal gland derived from a androstenedione pathway. This is why dutasteride and finasteride are especially important despite taking strong anti-androgens.
View attachment 123499
There is something similar in prostate cancer patients. Where its believed there are mutations in a gene expression that causes an increase in DHT production, specifically from the adrenal gland. These patients are usually on anti-androgens such as cypro, bical and dutasteride, but their DHT still increases locally in tumors.
Here's a source if you want to read more.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367713/
"Chang et al. show that, contrary to widely held assumptions, the dominant pathway to DHT synthesis does not involve testosterone as a precursor to DHT, but instead involves the conversion of Δ4-androstenedione (AD) to 5α-dione (AD→5α-dione→DHT) by the steroid-5α-reductase isoenzyme 1 (SRD5A1)."