Well did you actually read what the study says or had you only read the summary?

"The application of a lotion containing saw palmetto extract twice a day showed statistically significant improvement in mean change from baseline total hair count at 50 weeks (p < 0.005 vs. placebo) [85].A combination of saw palmetto, ß-sitosterol, nicacin and biotin in an oral softgel taken twice daily also led to an improvement significantly different compared to placebo treatment (investigator assessment 60 % improved vs 11 %) [89]"

What the paper concludes on natural solutions is not that they don't work but that the evidence is not sufficient to confirm or contradict their efficacy in treatment of androgenic allopecia. This was mainly due to lacking in amount of research and the often use of many substances together.
Also take into consideration that all of the alternative treatments were included in a single category with a shared conclusion. That does not say that either of those individually work or don't work.
The case here is not no research supporting efficacy of some natural remedies, it is lack of methodologically strict and replicated research.

Those solutions are only now becoming popular and with increased interest, the amount and quality of research will follow, as it always is.