Minoxidil (vasodilatation) and microneedling (angiogenese) increase the blood flow in the scalp. More oxygen in the scalp means less DHT produced locally.
https://aicepola.com/#causes
So by using minoxidil and microneedling you're indirectly reducing the DHT in your scalp.
Nonetheless, putting a 5 mg finasteride tablet in your minoxidil bottle might give you even better results.
The enzymatic conversion of testosterone to dihydrotestosterone is oxygen dependent. In low-oxygen environments, the conversion of testosterone to dihydrotestosterone is favored; whereas in high-oxygen environments, more testosterone is converted to estradiol.
https://aicepola.com/#causes
So by using minoxidil and microneedling you're indirectly reducing the DHT in your scalp.
Nonetheless, putting a 5 mg finasteride tablet in your minoxidil bottle might give you even better results.