2009年的一项研究暗示补充肌酸可能会使脱发恶化。[1]在该RCT中,服用肌酸的男性血液中的双氢睾酮(DHT)含量显着增加,而双氢睾酮是导致脱发的雄激素,尤其是男性。由于肌酸是可靠地提高性能的少数补充剂之一,并且具有良好的安全性,因此[2]这种副作用将是最不希望的启示。那么,您是否担心肌酸会导致头发脱落呢?
什么原因导致脱发?
在男性中,脱发的发展相对了解。通过与毛囊相互作用,DHT可以引起脱发。[3] [4]由于DHT敏感性或其他原因,给定的头发或多或少容易掉落取决于其位置(在男性型脱发中,头顶和发际线先变薄)和您的遗传遗产。[5] [6]
DHT是另一种雄激素的代谢产物:睾丸激素。一种称为5-α-还原酶的酶将游离睾丸激素(未与血清白蛋白或性激素结合球蛋白(SHBG)结合的睾丸激素)转化为DHT。[7] DHT可以与头皮毛囊上的受体结合,使它们随着时间的流逝而收缩并停止生发。[8] [9]阻止5-α-还原酶作用的药物,例如非那雄胺(Propecia),在预防脱发方面非常有效。[10]
在女性中,脱发的发展还不太清楚。遗传因素确实导致女性脱发,但女性识别基因的重要性不及男性识别基因的重要性。[11]同样,人们认为DHT在女性脱发中的作用较小。[12]其他因素,例如雌激素水平,被认为对女性脱发有一定影响,但这里又有相互矛盾的证据。[13]
双氢睾酮(DHT)和遗传学在男性型脱发中起主要作用,而在女性型脱发中起次要作用。与引起男性脱发的因素相比,引起女性脱发的因素还不太清楚。
服用肌酸会导致脱发吗?
只有一项RCT将肌酸补充与DHT升高联系起来。[1]这项研究是在20名健康的年轻男性橄榄球运动员中进行的,随机分为两组:一组服用安慰剂,而另一组服用7天负荷剂量(25 g /天)补充肌酸一水合物,然后维持剂量(5 g /天),持续14天,两组之间睾丸激素的变化无显着差异。但在肌酸组第7天(比基线高0.44 ng / mL,约56.1%)和第21天(比基线高0.12 ng / mL,约40.8%)的DHT显著增加。
对该研究的公开回应主要询问方法,但未发现统计错误。[14]值得注意的是,这项研究测试了其肌酸中25种不同的潜在掺假物,例如兴奋剂和雄激素类固醇。[14]未检测到任何东西,排除了DHT的变化是由于非法污染物引起的可能性。
迄今为止,这是唯一的RCT测试肌酸对DHT的作用。但是,许多研究测试了肌酸对睾丸激素的作用。在6天[15]和7天中,每天补充20 g肌酸时,只有两个RCT的睾丸激素显着增加。[16]十个RCT发现肌酸对睾丸激素没有作用。[17] [18] [19] [1] [20] [21] [22] [23] [24] [25]这些RCT的持续时间从6天到10周不等,使用的肌酸一水合物剂量范围是3到10周。 25克/天。一项使用苹果酸苹果酸的随机对照试验也未见对睾丸激素水平的影响。[26]重要的是,这些RCT中有五个专门测试了肌酸对游离睾丸激素的作用,该形式转化为DHT。所有人都没有看到明显的增加。[17] [20] [22] [18] [24]
正如一项研究中报道的那样,肌酸是否有可能在不增加睾丸激素的情况下增加DHT?实际上,是的,至少有两种方式。首先,肌酸可能不会显着增加游离睾丸激素,但会显着增加DHT(即,游离睾丸激素(DHT的基础物质)少量增加,可能导致DHT的增加更大。其次,肌酸可能会上调5-α-还原酶,该酶可将游离睾丸激素转化为DHT。一个或两个假设可能是正确的。还是都不是。当前的证据根本不允许我们采取立场。
在得出结论之前,我们需要提到三个警告。
1,这些研究都是在健康的年轻男性中进行的,除了一项是在运动员或其他受过训练的个人中进行的。
2,在一项研究DHT并发现其升高的研究中,DHT保持在正常范围内。所以即使当肌酸增加DHT,它仍然可能不会导致比否则将出现更强的毛发损失。
3,这也是最重要的:尚未直接研究补充肌酸对脱发的作用,因此我们只能做有根据的猜测。
总结
只有一项研究检查了肌酸与DHT的联系(然后,仅在男性中),但许多其他研究表明,肌酸不会影响睾丸激素的水平,而且由于DHT是睾丸激素的代谢产物,因此有人怀疑肌酸确实会增加DHT。如果是这样,那么是的,它可能导致脱发。但是,请记住,DHT只是导致脱发的众多因素之一;血液中DHT含量的增加并不能保证头发会脱落。迄今为止,还没有研究直接检查肌酸对脱发的影响。
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