這幾天到處可見關於鋸棕櫚生髮水用來治療雄性禿的新聞，每當有這類的新聞時，大家再心裡最常提出的一個問題，就是『有沒有效』？要怎樣去看待鋸棕櫚改善雄性禿這件事呢？我們試著以客觀的角度來給大家一些意見。

鋸棕櫚籽粹取(saw Palmetto Berry Extract / SPE)，或稱棕櫚樹果實(serenoa repens)，學名叫做Permixon，百年前就被印地安人用來改善攝護腺分面的問題，歐美也廣泛應用在攝護腺症狀的改善與預防上。所以，他並非是所謂的新藥，且對於雄性禿朋友來說，也是早已熟知的成份了，只是現在再經由媒體的介紹，也讓更多人能夠去了解他的用途了。

**有效、無效？**

若是有雄性禿掉髮，大概就要接受頭髮會慢慢離家出走的窘境，且必須要認知到，一旦停止治療，頭髮就會逐漸掉落到治療前的樣子，甚至更嚴重的事實，也因此，我們總希望有一樣藥品或是非藥品是能夠有效治療雄性禿的，但是事實上卻不是如此。不論柔沛與落建，都只是可以緩和掉髮與再生部分頭髮，而無法長回全部的頭髮，原因在於無法100%阻斷DHT荷爾蒙對毛囊的影響，口服或是外用的鋸棕櫚，也是如此；即便是使用之後有效，也一樣要不間斷的。

有些人說，鋸棕櫚沒有醫學根據，也是一種偏方；有些人說，鋸棕櫚的確可以改善雄性禿，這樣兩極的褒貶，在我看來是沒有意義的。我們可以舉出好幾篇的學術論文來證明鋸棕櫚可以降低DHT，我們也可以緊守醫學標準，非FDA許可的產品不用，非得堅持Minoxidil、Finasteride、雷射梳或是植髮手術不可。 Anyway，就讓這兩派說法繼續堅持己見好了，我只想為有雄性禿困擾的朋友，找出多一個可行的方案。

鋸棕櫚萃取物，也已經被證實可以有效減少毛囊細胞受體與DHT的結合，這實在勿需爭議；也因此有些生技公司會用來研發含有SPE的頭皮配方，並也確實具有阻斷DHT的功效。回到老問題身上，一定有效？多有效？怎麼預期效果？那當然還是要看自己掉髮的情況如何。如果是初期的雄性禿，外用鋸棕櫚不失為一個非藥物的替代方案，合理的預期效果一樣是緩和掉髮或是長回部份頭髮，當然也可能效果不彰。如果已經是較為嚴重的雄性禿(四期以上)，那鋸棕櫚也不可能有明顯的效果了。此外，鋸棕櫚若用來搭配落建若是柔沛(波斯卡)，也有相輔相成之效，但就要先衡量自己的經濟能力了。

**外用？口服？**

如果柔沛或波斯卡讓人產生惱人的副作用時，口服鋸棕櫚可用來在替代藥物上；也可以用來做初期的預防，畢竟沒有人會先吃藥來預防雄性禿的發生；或者是在治療初期，不想這麼早服用口服藥。但市面上的這些產品，通常會多添加其他可以用來阻斷DHT的成分，如非洲刺梨(Pygeum)、綠茶中的兒茶素(Catechins)等，價格也會比單一成分的鋸棕櫚來的高一些，且來源地多是以美國為主。至於副作用部份，口服鋸棕櫚的副作用機率極少，在一個315人的研究中發現(D. Authie and J. Cauquil. A multicenter study of the efficacy of Permixon in daily practice. Pharmacol Clin; 5(56):3-13, 1987)，98%的服用者並沒有副作用產生，而最常見的副作用症狀多半為反胃或是輕微頭痛，口服鋸棕櫚為脂溶性，最好在進餐時服用，大概一到兩個小時就會被吸受。

至於外用鋸棕櫚，其實在一些養髮液上都可以見到，美國品牌的Revivogen(中譯.立髮健)、Hairgenesis(中譯.髮源)、Crinagen(中譯.快來俊)，歐系品牌的護蕾(Ducray)、 Phyto(髮朵)，這些產品的特性、效果優劣、價格高低也都具有差異性的。此外，鋸棕櫚萃取多半只是養髮液其中多種成分之一而已，並非是單一成分的產品。這類外用產品如果應用得宜，可以用來彌補口服藥在抑制DHT效果的不足，或是用來搭配落建生髮水，可以在外用的治療方式上，獲得更好的預期效果。但要注意的是，SPE本來就是一種油性物質，必須要能夠找出適合自己生活作息的使用方式，才能兼顧長期使用的穩定性。另外，SPE的副作用機率同樣較低，可能會有頭皮過敏的可能(紅腫痛癢)。

外用鋸棕櫚的效果在實證上，確實是比口服鋸棕櫚更加完整可信的，盡量以外用為首選，但外用產品畢竟是比口服麻煩一些，要能夠耐心使用才有意義。總之，我們都可以跟自己的需求來決定要口服還是外用囉。

**我要用嗎？**

要不要使用，在於個人選擇。鋸棕櫚的優點是副作用低，也不會有男性功能障礙，讓我們在阻斷DHT荷爾蒙上，有更多且更彈性的選擇方式。至於鉅棕櫚的缺點則是需要有更大規模的臨床資料來證實其效度與信度。我還是想提醒大家，不是新聞報等之後，就表示一定有效，還是要認清自己的需求、充分了解鋸棕櫚特性與合理預期效果，才能有效利用鋸棕櫚來改善雄性禿囉。

**外用SPE的學術論文 **

1. Human prostatic steroid 5 alpha-reductase isoforms--a comparative study of selective inhibitors.

This study suggests that Fenistride (active ingredient of Propecia) only inhibited the Type 2 form of 5 alpha reductase where Saw Palmetto extract inhibited both type 1 and 2 forms of 5 alpha-reductase and was more potent than Fenistride. J Steroid Biochem Mol Biol, 54: 5-6, 1995 Sep, 273-9

2. Testosterone metabolism in primary cultures of human prostate epithelial cells and fibroblasts.

This Study shows that Fenistride and 4-MA inhibited the formation of some testostrone Metabolites (including DHT), where as Saw Palmetto inhibited the formation of all the Testostrone metabolites studied. J Steroid Biochem Mol Biol, 55: 3-4, 1995 Dec, 375-83

3. The effect of Permixon on androgen receptors.

This study shows that Saw Palmetto extract was able to effectively reduce Binding of Testostrone and DHT to their receptors on various tissues. Acta Obstet Gynecol Scand, 67: 5, 1988, 397-9

4. Prager N, Bickett K, French N, Marcovici G. A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. J Altern Complement Med. 2002 Apr;8(2):143-52

可參考資料--SAW PALMETTO From Dr.**Raztec**

This is by far the most commonly recognized and discussed herb concerning the prostate. Before we even begin its discussion, I highly recommend reading the book entitled "Saw Palmetto: Nature's Prostate Healer" by Ray Sahelian, M.D. This is a marvelous book that discusses the prostate and how Saw palmetto and other natural nutrients can prevent prostate disease (BPH).

Saw palmetto is a plant (dwarf palm tree) native to the United States. It has been used medicinally for over a century. Its first use was described in the medical literature in the 1800s. Early literature concerning Saw palmetto stated that it relieved symptoms ranging from prostate enlargement in men to gynecological problems in women, such as menstrual discomfort. It has even been described as a potential aphrodisiac.

Saw palmetto contains hundreds of different substances that can account for its beneficial effects. Saw palmetto is usually distributed as a crushed berry or as an extract. The extract form contains most of the substances found to be effective in treating benign prostatic enlargement. The extract form has been shown to be more potent than the dried berry form. The extract, then, is the form of choice.

There are many articles in the medical literature that establish the efficacy of Saw palmetto in treating benign prostatic hyperplasia. One of the most recent and prestigious articles is "Saw Palmetto Extracts for the Treatment of Benign Prostatic Hyperplasia: a Systematic Review" by Timothy J. Wilt, MD, MPH et al. It appeared in The Journal of the American Medical Association on November 11, 1998 [2]. The study clearly demonstrated that the use of Saw palmetto improved urinary tract symptoms associated with benign prostatic hyperplasia. It also demonstrated that Saw palmetto provided similar improvement in urinary tract symptoms when compared to drugs such as finasteride. Saw palmetto was associated with fewer side effects. Although the mean study duration (the period of time that participants were using Saw palmetto) was 9 weeks, participants were noticing positive results in as little as 4 weeks. Finasteride users commonly saw relief of symptoms after three months.

The next three paragraphs are a bit technical, but some readers may appreciate the detail. Others may wish to skip ahead to the paragraph that begins, “It is clear that….”

A total of 18 randomized controlled trials involving 2939 men who met inclusion criteria were analyzed. Treatment allocation concealment was adequate in 9 studies (i.e., they were single-blind tests), whereas 16 studies were double-blinded. The average duration of the study was 9 weeks. In comparison to the men in the placebo control group, men treated with the SP extract Serenoa repens (S. repens or Saw palmetto) showed a measurable improvement in urinary tract symptoms. The weighted average difference for patients treated with S. repens was -1.41 points with a 95% confidence interval of L2.52, -0.301, compared to the control group's weighted-mean difference of -0.76 with a 95% confidence interval of [-1.22, -0.32]. This represents a relative weighted mean difference of 46% (Here, a lower weighted-mean difference correlates with improved urinary tract function). The patients themselves provided self-improvement ratings in urinary tract symptoms that were highly correlated with their quantitative evaluations.

Compared with men receiving finasteride, men treated with S. repens showed similar improvements in urinary tract scores. The main advantage of treatment of BPH with S. repens over finasteride was apparent in the decreased incidence of adverse side effects. For example, 4.9% of patients treated with finasteride reported erectile dysfunction compared with 1.1% of patients treated with S. repens. These percentages are based on the Neyman-Pearson binary hypothesis test with power function parameter P set to P<0.001. That is, the probability of a Type-II error was fixed at 0.999. Here, a Type-II error refers to the probability of accepting the null hypothesis H_0 (no urinary tract improvement) when the alternative hypothesis H_1 (urinary tract improvement) is actually true. The significance level for all randomized trials was set at 0.05, thus indicating a probability of 0.05 of rejecting H_0 when H_1 is true.

Some key points regarding these results are in order here. First, since all the statistical studies are based on classical (or frequentist) methods, all inferences derived from them are inherently indirect. That is, no direct claims can be made regarding the probabilities of improved urinary tract function. Rather, one can only infer the probabilities that the treatment did not fail. This is by no means a fallacy, neither on the part of the researchers nor on the methods of data acquisition, but is an inherent aspect of frequentist analysis. To emphasize this point further, consider the value of the mean-weighted difference for patients treated with S. repens. The reported value was -1.41. Note that this is not a true statistical estimate of this parameter. Rather, it is a measured value that has a 95% probability of being contained in the random interval [2.52,-0.30]. If one wished to make direct inferences from the data, non-classical statistical analyses, such as those based on Bayesian decision theory, should be employed [3]. Another point worth mentioning concerns the sensitivities of the tests. Since the studies did not report the standard errors of the differences between the means of S. repens and control, the authors assessed the sensitivity of the tests by analyzing data for three different values of correlation coefficients, namely (0.25, 0.50, 0.75). The work, then, reported "no significant statistical difference in outcomes according to the three correlation coefficients." As a result, the correlation coefficient was arbitrarily set to 0.50. One could certainly argue that this is a somewhat ad-hoc approach. To be more precise and more objective, the correlation coefficient could have (and should have) been estimated by a standard technique such as the method of maximum likelihood [4] or via another point estimator such as the Bayesian minimum mean square error (MMSE) estimator or even the Bayesian maximum a-posteriori (MAP) estimator [5]. This would certainly have altered the calculated relative weighted mean difference from its reported value of 46%, but to what degree is unknown. Note that the relative weighted mean difference of 46% was not actually reported in the JAMA article [1] but rather was calculated by the current authors based on the results in [1].

It is clear that there was an improvement in patients given Saw palmetto over the placebo-control group, and, moreover, the improved urinary tract function paralleled that which was displayed by patients taking finasteride. This study clearly demonstrated that the use of Saw palmetto improved urinary tract symptoms associated with BPH, and that its effects were in concert with the improvements achieved through the use of finasteride. It was also shown that, compared to finasteride, Saw palmetto administration produced a lower incidence of adverse side effects. The mean duration of the study encompassed 9 weeks of Saw palmetto administration. However, many participants were reporting positive results in as little as 4 weeks.

Both Saw palmetto and finasteride were found to be effective in the treatment of benign prostatic hyperplasia (BPH). This study clearly establishes the role of Saw palmetto in combating the effects of DHT. Note that Saw palmetto was compared to 5 mg of finasteride in this study and that Propecia contains only 1 mg of finasteride.

Side effects experienced with Saw palmetto are infrequent. One three-year study with 315 patients showed that 98% of the patient population had no significant side effects [6]. The most common side effects experienced with Saw palmetto include nausea and mild headache. Since Saw palmetto is fat-soluble, it is better to take it with meals. It usually takes one to two hours to be absorbed.

References (relating to Saw palmetto)

1. Gormley GJ, et al. The effect of finasteride in men with benign prostatic hyperplasia. N Engl J Med;327:1185-1191,1992.

2. T.J. Wilt, A. Ishani, G. Stark, R. MacDonald, J. Lau, and C. Muirow. Saw Palmetto extracts for treatment of benign prostatic

hyperplasia.JAMA;280(18)1604-1609, 1998.

3. J. O'Berger, Statistical Decision Theory and Bayesian Analysis, 2nd Ed., Springer Verlag Series in Statistics, Springer,1985.

4. PJ. Bickel and K.A. Doksum, Mathematical Statistics -- Basic Ideas and Selected Topics, Prentice Hall, Englewood Cliffs, NJ, 1977.

5. A. O'Hagan, Kendall's Advanced Theory of Statistics, Volume 2B: Bayesian Inference, Halsted Press, New York, 1994.

6. D. Authie and J. Cauquil. A multicenter study of the efficacy of Permixon in daily practice. Pharmacol Clin; 5(56):3-13, 1987.