I think you can get a finasteride prescription from your general physician.
Let's see what drugs.com says about
finasteride. No, let's just use Wikipedia.
Adverse effects
A 2010 Cochrane review concluded that adverse effects from finasteride are rare when used for BPH.[8] When finasteride was originally approved for hair loss in 1997, the FDA reported that it appeared well tolerated, with the most common side effects being related to sexual function.[35]
The FDA has added a warning to 5α-reductase inhibitors concerning an increased risk of high-grade prostate cancer, as the treatment of BPH lowers PSA (prostate-specific antigen), which could mask the development of prostate cancer.[36][37] Although overall incidence of male breast cancer in clinical trials for finasteride 5 mg was not increased, there are post-marketing reports of breast cancer in association with its use, though available evidence does not provide clarity as to whether there is a causative relationship between finasteride and these cancers.[23][38] Some men develop gynecomastia (breast development or enlargement) following finasteride usage.[39][40][41][42] The risk of gynecomastia with 5α-reductase inhibitors is low at about 2.8%.[43]
Sexual dysfunction
Finasteride causes short-term sexual dysfunction in some men.[9] Whether finasteride causes long-term sexual dysfunction in some men after stopping drug treatment is unclear.[44] There are case reports of persistent diminished libido or erectile dysfunction after stopping the drug and the FDA has updated the label to inform people of these reports.[9][45][43]
The 2010 Cochrane review found that compared with placebo, men taking finasteride are at increased risk for impotence, erectile dysfunction, decreased libido, and ejaculation disorder for the first year of treatment; the rates of these effects became indistinguishable from placebo after 2–4 years and these side effects usually got better over time.[8] Another 2010 review found that when used for hair loss finasteride increased rates of sexual problems.[46] A 2016 meta-analysis found that sexual dysfunction, including erectile dysfunction, loss of libido, and reduced ejaculate, may occur in 3.4 to 15.8% of men treated with finasteride or dutasteride.[21] This adverse effect has been linked to lower quality of life and can cause stress in relationships.[47]
I have had problems with impotence, but I don't attribute it to finasteride. I think it's more related to porn-overdose* and
SSRI usage.
*There is dispute if this can lead to impotence, but I had the effect before.