Finasteride customized dosage for hair loss, is it correct?

every other day likely works the same.

You need a formal evaluation to see what type of hair loss you may have. when you have hairless its best to do a full hormonal workup for internal optimization plus scalp biopsies or scrapings to rule out any stress related, inflammatory, autoimmune or infectious causes of hair loss. In general most people with early hair loss have telogen (stress related) and/or androgenetic (normal aging) and both can be treated with in office treatments like steroid injections, PRP/acell, Exosomes and at home treatments like oral medications, oral vitamins like Viviscal, topical exfoliating sprays like Restorsea, and weekly growth factors like anteagemd. See an expert for an evaluation. If hair loss is significant it may requires hair transplant (follicular unit translation).

Firstly, thanks so much for asking this question. My first question in response is how effective is finasteride in treating hair loss when taken daily? And then rather than considering taking a marginally effective treatment less often, perhaps we should look to a newer and better approach instead?

Finasteride has been around as a treatment for hair loss for nearly 40 years, after it was noticed as a side effect in trials for its treatment for prostate cancer than some participants stopped losing hair and some even regrew a little. Now you will notice here that I did not say that everyone stopped losing hair nor that they regrew all their hair - because that was not the case. Even today - propecia/finasteride has been most effective at slowing down hair loss progression for most people with some even seeing a little regrowth (most commonly when combined with Rogaine - which does contain a mild hair regrowth stimulant as part of its make-up).

Thanks to the birth of precision medicine several years ago - which for some reason most practicing doctors have not embraced - however I am happy that new medical schools are now training their graduates as functional medicine doctors which is based on the precision medicine approach of understanding the underlying root cause of any condition and not just treating symptoms with multi-line standard regimes.

In treating any condition, accurate diagnosis is the first most important step.
Find a precision medicine hair regrowth specialist who will first perform detailed lab tests such a the Biochemical Report Card to first identify all the biomarkers contributing to your hair loss and then create you a personalized formula to both stop your hair loss and regrow your hair.
Everyone is different, and I have found that a one size fits all approach will not work to effectively regrow everyone's hair. Precision Medicine is the only answer.

In the original Merck studies, doses ranging from 0.1mg to 10 mgs were tested, so we know that low dosing does still have an impact, for example 0.25 mgs (1/4 normal dose) has 50% of the value for hair loss. It is also known that finasteride works at the hair level where tissue fixation lasts far longer than blood levels.