I agree with you James, oral minoxidil needs to be handled with extra care.
I don't recommend using high dosages of oral minoxidil for long periods. I'm just testing it and being careful by constantly monitoring the heart rate with a fitness tracker.
Unfortunately I don't respond to 50 mg of minoxidil applied topically (1 mL), but I respond to 6 mg (3 drops) taken orally. I do plan to reduce it to 2 mg (1 drop) in the future just for maintenance.
The increased heart rate can be useful when you do sports, or just very active. But an increased heart rate in the night when you're trying to rest only has disadvantages.
By the way, I'm also using 0,05 % tretinoin (2 days a week) and microneeding (once a week) to enhance minoxidil results.
The advantage of oral form is that you kind of know how much it is going systemic, with topical form it varies a lot from scalp to scalp. Just by washing your hair with hot/warm water before will open pores and increase the topical absorption.
I had my first experience with minoxidil many years ago in my early twenties and was using it topically twice a day. The side effects were scary.
On one occasion I was walking and had a scary chest pain, it made me give up using it completely. I also got a eye twitch that remained for many years even after discontinuing the use of minoxidil.
So in my experience using topical minoxidil (100 mg) twice a day can be more dangerous than using it orally only once (6 mg).
I do understand your warning, minoxidil should be taken with care, especially if in oral form, since most of it goes systemic.
By the way, I know that you're a big advocate for tretinoin.
Some studies report that it increases VEGF and angiogenesis like minoxidil or microneedling, but other studies actually report that it does the opposite.
What's your take on it? Thanks!