I am not looking to feed this troll but just to clarify this misinformation being pushed to others who may read this thread:
I find it highly unlikely that alloP drops significantly in https://sci-hub.se/10.1515/hmbci.2010.010 in the plasma but assuming it isn't a proxy for what's happening in the brain is short sighted. Especially cause it continually drops at every increment up to 1 year.
Also, the study you site to say that dutasteride doesn't reduce alloP is titled:
5α-Reductase Inhibition Prevents the Luteal Phase Increase in Plasma Allopregnanolone Levels and Mitigates Symptoms in Women with Premenstrual Dysphoric Disorder
This study uses Finasteride which does not inhibit 5 Alpha Reductase type 1 to any significant degree. 5AR type 1 is the primary type of 5AR in the brain. This is common knowledge. Yet somehow you come to the conclusion that plasma is a proxy for what's happening in the brain.
Allopregnanolone is not only produced in the brain. It's also produced in the adrenal cortex and this is the main source of circulating allopregnanolone. It can be produced anywhere Progesterone, 5AR, and 3α-HSD are present.
The present study firstly showed that allopregnanolone levels are reduced both in AD and in VD and that dementia has a preserved stimulated response of allopregnanolone to CRF. Overall, however, the total response of allopregnanolone to CRF remains reduced in respect to controls. Further studies...
pubmed.ncbi.nlm.nih.gov
A major neurosteroid gamma-aminobutyric acid (GABA) agonist is allopregnanolone: the main source of circulating allopregnanolone is the adrenal cortex.
https://pubmed.ncbi.nlm.nih.gov/24172649/
It is less well appreciated that progesterone and its metabolite allopregnanolone are also male hormones, as they are produced in both sexes by the adrenal glands. In addition, they are synthesized within the nervous system.
Allopregnanolone, today best known as brexanolone and marketed as Zulresso for the treatment of postpartum depression is now part of only two recently US Foo...
www.frontiersin.org
Acute stress in rodents fast induces allopregnanolone biosynthesis underlying its role in stress response and demonstrating allopregnanolone present in brain is synthesized independently from peripheral glands (24).
Finasteride in humans, not rats, would only inhibit the allopregnanolone being produced via progesterone being metabolized by 5AR2 and then 3α-HSD which would not be in the brain. In rats, Finasteride has similar affinity to 5AR1 as 5AR2 so it's not comparable to humans. Saying it's shortsighted to not assume that plasma levels of allopregnanolone are a proxy for what is happening in the brain is... shortsighted.
The study I posted on PMDD was done on humans, used dutasteride, and it showed that .5 mg a day was not enough to stabilize allopregnanolone levels in brain based on plasma levels AND symptoms but 2.5 mg was. The key word here is stabilize. Ask yourself, if dutasteride inhibiting allopregnanolone in the brain was so detrimental, why would they be using this as a treatment and why did it work?
ajp.psychiatryonline.org
why would allopregnanolone antagonism prevent symptoms of PMDD? Apart from the obvious—that women’s reproductive-related mood disorders are not all the same—sepranolone and dutasteride also stabilize allopregnanolone signaling. As such, their efficacy is consistent with observations that changes in hormone levels (as opposed to the levels themselves) are important regulatory signals, a well-described phenomenon in the form of fast-rate feedback of ACTH secretion (16) or pulsatile frequency-dependent actions of gonadotropin hormone-releasing hormone on gonadotropin release (17).
This is from a psychiatry journal. Notice they state that dutasteride stabilizes allopregnanolone signaling and not inhibits? This is what I was trying to extrapolate on before, perhaps poorly since it was ignored, in regards to more allopregnanolone is not always necessarily good. It's seem to be more important to have stable levels which dutasteride apparently provides in PMDD patients and it would presumably do so in males as well.
Here is yet more evidence that neither Finasteride nor Dutasteride increase the risk for Dementia.
As the strength of the association decreased with increased exposure, the higher risk seen in the initial two years likely represents the presentation and treatment of urinary symptoms which coexist with mild cognitive impairment and eventually progresses to a diagnosis of dementia.
pubmed.ncbi.nlm.nih.gov
Results: New initiation of 5ARI medication was associated with an increased risk of dementia during the first (HR 2.18, 95% CI 2.01-2.35) and second (HR 1.52, 95% CI 1.39-1.67) year, however this risk was nonsignificant among the men with the longest exposure to 5ARIs (HR 1.06, 95% CI 0.98-1.14). There was no difference in the results between types of 5ARIs.
Conclusion: As the strength of the association decreased with increased exposure, the higher risk seen in the initial two years likely represents the presentation and treatment of urinary symptoms which coexist with mild cognitive impairment and eventually progresses to a diagnosis of dementia.
If the "inhibition" of allopregnanolone in the brain by dutasteride was linked to dementia, the strength of association would not decrease with increased exposure. It would increase.
The reduction of serum allopregnanolone with 5ARI is to be expected and this inhibition is primarily the allopregnanolone from the adrenal cortex, not the brain. The only human study that I'm aware of looking at allopregnanolone and dutasteride had to use 2.5 mg ED to stabilize allopregnanolone levels in the brain in women with PMDD.
This is why I believe the concerns around 5ARI and allopregnanolone are really just massively overblown hype with no real convincing evidence to support it.
There is a real potential risk with 5ARI's though and it is curious how it is ignored and people choose to focus on meme tier PFS foundation cash grab topics like "allopregnanolone" instead. Probably because of the internet bro science hype.
There are multiple studies showing reduced insulin sensitivity and increased diabetes risk with finasteride and dutasteride although there is at least one that contradicts these and as of 2019, some of the top endocrinologists in the world had no answers to this discrepancy. If there is anything to worry about in regards to safety with taking a 5ARI, this would be it. It is better to be aware of this potentially increased risk so that lifestyle choices can be modified to mitigate any increased risk.
This thread discusses the studies surrounding this issue.
https://www.hairlosstalk.com/intera...associated-with-metabolic-alterations.106703/