落髮問題同時發生在男性與女性身上。在落髮問題中，因為雄性激素造成的雄性禿占大多數。雄性禿的區域多從顳部開始，一直延伸到前額還有頭頂區域。然而後枕部的頭髮則是因為毛囊缺乏雄性激素接受器而不受雄性激素所影響。影響雄性禿中一個很重要的脢即是 5 alpha-reductase(還原脢)，5 alpha-reductase( 還 原 脢 ) 可 以 將 細 胞 內 的 testosterone( 睪 固 酮 ) 轉 換 為dihydrotestosterone(DHT)(二氫睪固酮)。某些植物的萃取物中的植化素有抑制5 alpha-reductase(還原脢)的功效。鋸棕櫚則是其中一種，而且在歐洲已經被廣泛使用在治療攝護腺肥大。在本篇，我們根據”鋸棕櫚的抑制 5 alpha-reductase(還原脢)效果，是否有促進人類頭髮生長的功效”作系統回顧。我們以 PubMed， Cochrane，以及 WOS 作為搜尋。關鍵字為: 5 alpha-reductase，serenoa repens 以及 human hair growth。總共有四篇論文為主要系統回顧內容。鋸棕櫚的萃取物不論是外用或是口服，皆能減少雄性禿惡化。外用的製劑能增加永久毛(terminal hair)的數量，而口服製劑則能穩定落髮狀況不再惡化，或是增加生長期毛囊的數量。但效果仍不如使用藥物(Finasteride)在前額及頂部都有作用。使用鋸棕櫚治療雄性禿是安全的，而且不會造成性功能障礙的副作用。
Background
Hair loss problem affect both men and women. Androgenic alopecia (AGA) is the most common type of male pattern hair loss. The hair loss pattern usually begins with bitemporal recession, followed by the frontal and vertex areas. But the occipital area is not affected by androgen activity due to lack of androgen receptor.
The enzyme 5 alpha-reductase plays on important role in AGA. The conversion of
testosterone to dihydrotestosterone (DHT) is catalyzed by the enzyme 5 alpha-reductase.
Several plants were noted as having 5 alpha-reductase inhibition potential due to its phytochemicals. Serenoa repens is one of these plants which have been common used in Europe for benign prostate hyperplasia. Systemic review was used to investigate the improving human hair growth effect of Serena Repens.
Objectives
This systematic review aimed to assess the effects and harms of Serenoa
repens in the treatment of men with androgenic alopecia.
Search method
We use PubMed as our primary research database. The Cochrane and WOS were also searched.
Selection Criteria
The following keywords were used for searching: 5 alpha-reductase, serenoa
repens and human hair growth.
Result
There are four literatures meet the criteria of our study. It seems effective to treat AGA through topical use and oral treatment. In the topical use study, the terminal hair counts continue increasing at end of trial. Although different formulation of serenoa repens extract, the stabilization of hair loss condition and improving the hair bulb phase proportion are the relative noteworthy effect. In the serenoa repens and finasteride comparison study, serenoa repens lead an improvement only in vertex. Finasteride improved hair growth in all area.
Conclusion
The products of serenoa repens extract, in topical use or oral intake form, are safe and no sexual dysfunction side effect which was one of concerned reason by patients.
