Why isn’t minoxidil enough for hair regrowth?

I’ve been reading a lot about male pattern hair loss lately(androgenetic alopecia). Most often finasteride is said to be a requirement for hair loss and if you don’t use it, it’s an uphill battle.

From my understanding (if nutrition, hormones, exercise, etc is good) DHT causes hair loss due to reduced blood flow and shrinking of the hair follicle. If so, why wouldn’t minoxidil which increases blood flow and even brings back hairs from a baby state to a terminal hair during usage, be enough? Microneedling has a very similar effect, with great backing.

DHT blockers cause issues for many with varying effect. It changes your hormone levels, there’s no question about it. Most doctors I spoke to were against that as a young male, because of the terrible repercussions. I did however take Min + Fin solution for 3 weeks (local treatment, no pills). Did blood work and have higher estradiol. Will get further testing, but not interesting on messing myself. Off fin and will retest myself again after stabilization (month later).  This question was taken from Reddit 12/15/2024 with my answer below. 

I can’t write a textbook for you in answering your questions, so I am going to discuss only two classes of drugs, (1) DHT blockers and (2) Minoxidil. 

DHT blockers work effectively at the hair follicle level blocking DHT in a competitive inhibition with the enzyme 5 alpha-reductase with 70% effectiveness for finasteride and greater than possibly greater than 90% with dustasteride. DHT works in many body organs, so blocking at the hair follicle level, will lead to blocking at other organ systems as well.  Dutasteride blocks more receptors than finasteride and it has not been approved for hair loss by the FDA in the US. Finasteride was the first drug to be approved for DHT blocking hair loss drugs around 1996-7 timeframe.

Minoxidil was developed as an antihypertensive drug, which did not work consistently at controlling blood pressure; however, many women complained about hair growth on the face and body when taking it.  When it was applied topically, it grew hair and less was absorbed systemically to impact blood pressure significantly. The mechanism of action is not that is increases blood flow as most people believe, it has its effect: by stimulating “ASC motility and increases paracrine growth factor signaling. Minoxidil-stimulated secretion of growth factors by ASCs that may enhance hair growth by promoting Dermal Papilla proliferation.”  Further, “Minoxidil directly promotes hair growth via the stimulation of dermal papilla (DP) and epithelial cells. Reference: https://pmc.ncbi.nlm.nih.gov/articles/PMC5877552/

So, as you see from above, both classes of drugs have different modes of action to get to hair growth. Minoxidil has been around much longer, and in countries like India, it has been used well before finasteride was even discovered as a drug for treating hair loss in genetic balding.  So if one drug doesn’t work, switch to the other, or sometimes take both. 

Minoxidil does not work like microneedling, see here for mechanism of action: https://baldingblog.com/does-microneedling-really-work/