This study is fucked, to put it bluntly. They're lumping together Fin and Dut and people taking 5mg Fin. Most people taking Fin for MPB take 1mg Fin, for example.

You can actually not draw any conclusions from this paper other than, don't use Dutesteride unless you're male to female transitioning and don't go above 1.25mg finasteride if you want to keep your hair and your dick.

But it just confounds everything together, it's a terrible study.

0.8% of a 4000+ sample size had PED with the regular dosage for baldness treatment. That's absurdly low and pretty much confirms that though the risk is there, it's highly unlikely. Its even more ridiculous that 1.4% of the ENTIRE sample size (over 11,000 people) taking less than or equal to 1.25mg of fin, greater than 1.25mg of fin, and dutasteride reported persistent ED.

As a fin user I actually find this data to be re-assuring.

The criterion of PED is also vague. It's basically asking people do they think their dicks are broken. There's enough guys going on Noporn/Nofap routines because they couldn't get it up one night with a girl because they're so used to watching porn and jerking off that real sex is too weird, and one bad experience and now they're convinced they have ED.

If you tell a guy suffering from baldness that there's "a good chance you're gonna break your dick if you drink this pill" you've already biased your study. Blind study is the only way.

I'm not suggesting there is no risk, at this point the numbers are just a joke. This study is another example of how to NOT to do it.

They're also just doing analysis on a static data set.

> PED was determined by manual review of medical narratives for all subjects with ED. Risk of an adverse effect was expressed as number needed to harm (NNH).

So this doesn't rule out the possibility of the subjects' mental state affecting their ED.

A little strange to see this at the very top of the site, doesn't look like anything particularly interesting?

My theory: it's a back-handed jab at President Trump, as he's reported to be a user of Propecia for hair loss. Overtly political stories are usually flagged off the front page quickly, but this is "just" a journal article.

(Note: I'm not a Trump supporter — quite the opposite. I just don't like round-about mocking: "Oh, he can't get it up. That must be why he's such a jerk!")

My theory: an overwhelming majority of HN readers are men, many of whom have taken or considered taking finasteride.

I'm a fin user and frankly I'm surprised to see this here. It's already well known that persistent ED is a potential side. I'm guessing its here because its a new study and other HN readers are curious about the drug (or taking it).

> Among men 16–42 years old and exposed to finasteride ≤1.25 mg/day, 34 of 4,284 (0.8%) developed PED (persistence median 1,534 days, IQR 651–2,351 days); the multivariable model predicting PED had one variable: duration of 5α-RI exposure

So less than 1% of finasteride users get PED. PED was already a known side effect. That's good it's being confirmed with data, but aren't the odds still very low that this would happen to fin users? As a fin user myself, I haven't experienced any of the sexual sides so I'm wondering if there's any new take-away from this.

When I look at this as a fin user, I'm personally happy to see that the data says its so unlikely.

Where is commonly found finasteride or dustaride?

Among other things, in a drug that is used to treat BPH (benign prostatic hyperplasia — a non-cancerous enlargement of the prostate), and male pattern hair loss. It's also sometimes used as a hormone replacement in FtM transgender individuals.

It's widely rumored that President Trump uses it for hair loss, which I suspect is part of why this article was shared, and is being upvoted; this side effect wasn't exactly unknown before this study...

they are used for treating prostrate enlargement as well as hair loss in men, among other things..

https://en.wikipedia.org/wiki/Finasteride https://en.wikipedia.org/wiki/Dutasteride

But I don't think that this side-effect was unknown. ED / sexual dysfunction is a documented side effect for both the drugs in a significant percentage of the patient population.

I think this study is exploring "persistent" ED, which is less known. ED is a documented side effect, but this shows that some men continue to experience ED even after they stop taking the drug.

The linked Wikipedia article cites references to persistent ED and diminished libido common enough to warrant changing the labeling on the drug in 2014.

So, yes, this study is exploring that side effect, but it's inaccurate to call it "less known".

EDIT: fixed some word salad phrasing.

The common brand names are Propecia and Proscar.

Propecia and Proscar are finasteride. The common brand for dutasteride is Avodart.

They are both drugs to treat enlarged prostate (benign prostatic hyperplasia)

Can anyone knowledgeable guess at the mechanism of action?

The Wikipedia article says it prevents conversion of testosterone into dihydrotestosterone by the enzyme 5α-reductase, and also affects the GABA system. Particularly relevant quote: "Reduction of GABA-A receptor activation by these neurosteroids has been implicated in depression, anxiety, and sexual dysfunction." More specific than that is way beyond my understanding of these things.

https://en.wikipedia.org/wiki/Finasteride#Mechanism_of_actio...

That's fine, but how would that account for PED?

Like I said, any more is beyond my level of understanding of these things. All I can say for sure is that the GABA system is incredibly important, and kinda delicate.

Read up on delirium tremens, for example: long-term alcoholics, and benzodiazepine and barbiturate addicts need to be really careful in stopping their use of those drugs — they could die if they aren't. Those drugs also affect the GABA system.

Maybe the long-term down-regulation of some aspect of GABA-A metabolism by finasteride's preventing the formation of an agonist for those receptors becomes permanent or semi-permanent after a while? I really don't know.

It blocks DHT, your body's strongest androgen.

I'm guessing this is a dig at someone of prominence having notable hair who is in US news who is on one of the drugs mentioned.