I've done a decent amount of research on Saw Palmetto, I've concluded that it's a weak 5ar inhibitor about half as effective as finasteride for both reducing DHT and halting hair loss. It may be worthwhile for people who got sides from finasteride (like myself).
Although it should be noted that sides are also possible from SP although I'd reckon about half as likely and half as strong. (Complete guess but all studies so far have shown less sides than finasteride)
I take 320mg 90% fatty acids and sterols everyday for 3 months. So far I've noticed decreased shedding (could be completely minoxidil related started both at the same time) and an increased libido. I will post back at the year mark!
It was used as a treatment for BPH, which is what finasteride was developed for. There are studies in vitro and studies on people showing that it inhibits DHT and helps with BPH and male pattern baldness.
Two year study, oral SP compared with finasteride.
https://www.ncbi.nlm.nih.gov/pubmed/23298508
>assessing usage of 320mg saw palmetto over the course of two years in otherwise healthy men with male pattern baldness noted that 38% of subjects treated with saw palmetto reported an increase in hair growth which performed less effectively than 1mg finasteride (66%);
https://www.ncbi.nlm.nih.gov/pubmed/12006122
>The liposterolic extract of saw palmetto (200mg of 85-95% liposterolic content) paired with 50mg β-sitosterol and some B-vitamins (Biotin at 100mcg and niacin at 15mg) in 10 otherwise healthy men with androgenic alopecia over the course of 18-24.7 weeks found that 60% of the subjects had their hair improved (blinded investigator-assessed) compared to one subject in placebo
Very recent study (2016) backing up it's effectiveness for BPH
http://www.ncbi.nlm.nih.gov/pubmed/27186566
Another recent study showing it effective for BPH
http://www.ncbi.nlm.nih.gov/pubmed/26817302
Recent study showing it's topically effective for hair growth over 24 weeks.
http://www.ncbi.nlm.nih.gov/pubmed/26010505
>The topical application of S. repens extract could be an alternative treatment in male pattern baldness in male patients who do not want or cannot tolerate the side-effects of standard medications, but the use of a concentrated S. repens product beyond 4 weeks may be necessary for sustained efficacy.
More
http://www.ehrs.org/conferenceabstracts/2004berlin/researchabstracts/P10-141-Fasulo.htm
>Conclusion: In accordance also with other authors, this study confirms the effectiveness of Serenoa repens extract on hair baldness such as androgenetic alopecia, especially when� connected with 5a reductase activity.
http://examine.com/supplements/saw+palmetto/
If you actually go through these you will conclude that saw palmetto works about half as well as finasteride for BPH and male pattern baldness and block about half as much DHT in vitro and prostatic tissue than finasteride.
If there are any opposing or supporting studies you know off I'd love to see them.
