生薑、辣椒塗塗抹抹？生髮僅2成分獲官方認可 優活健康資訊網／uho新聞部-2014年04月22日 下午14:28 （優活健康網記者陳承璋／採訪報導）你也有掉髮的困擾嗎？隨著愛美風潮逐漸流行，原本男性掉髮不太被受到重視，直到近幾年來，只要頂上頭髮稍微風吹草動，很可能會讓民眾擔心是不是遭到掉髮危機纏身，根據資料顯示，台灣有掉髮問題且感到擔憂的男性，從2007年的9%攀升至2013年的50％，激增幅度逾5倍，顯見台灣男性越來越重視自己的寶貝頭髮。
高達五成民眾 以為洗髮精能生髮 雖民眾擔心自己的頂上毛髮，然而根據調查顯示，我國民眾透過正規方法，解決問題卻少之又少；高達五成民眾，誤認為洗髮精能救髮，因此掉髮初期，往往把希望寄託在一瓶瓶高價昂貴的洗髮精上頭，另外，還有三成的民眾，選擇調整飲食作息，但皮膚科醫學會陳建?醫師指出，這些方法對治療掉髮幾乎無效，反而會延誤最佳治療時機。
目前僅有兩種聲髮成分 普遍被官方認可 陳建?醫師說，目前美國與台灣FDA認可的生髮成分，僅有含Minoxidil成分的外用生髮液，以及含Finasteride成分的口服藥，他說，雖這些成分能夠促進頭髮再生，但許多民眾時常以為一用就會見效，而不規律使用，恐怕也只是白花錢。他解釋生髮治療的效果，和是否正確、規律的使用有絕大的關聯性！許多患者因為三天捕魚兩天曬網，沒有規律使用生髮產品，導致效果不如預期；或是使用一兩個月就急於放棄。其實，每天早晚各使用一次、持續四個月以上，才是外用生髮治療要看到效果的不二法門。《優活》提醒／許多民眾碰到掉髮危機，時常會把頭皮當炒菜鍋，讓生薑或辣椒等刺激性食材抹上頭皮，或拿梳子猛梳頭皮以為能活血，滋養毛囊，但這些方法除了沒有科學根據，更可能引發嚴重毛囊炎，使掉髮更加嚴重，因此有掉髮困擾，務必尋找專業皮膚科醫師，求得最佳的生髮建議。
Finasteride (brand names Proscar and Propecia by Merck, among other generic names) is a synthetic drug for the treatment of benign prostatic hyperplasia (BPH) and male pattern baldness (MPB). Testosterone in males is produced primarily in the testicles, but also in the adrenal glands. The majority of testosterone in the body is bound to sex hormone-binding globulin (SHBG), a protein produced in the liver that transports testosterone through the bloodstream, prevents its metabolism, and prolongs its half-life. Once it becomes unbound from SHBG, free testosterone can enter cells throughout the body. In certain tissues, notably the scalp, skin, and prostate, testosterone is converted into 5α-dihydrotestosterone (DHT) by the enzyme 5α-reductase. DHT is a more powerful androgen than testosterone (as it has approximately 3-10 times the potency at the androgen receptor, the site of action of the androgen hormones), so 5α-reductase can be thought to amplify the androgenic effect of testosterone in the tissues in which it's found. Finasteride, a 4-azasteroid and analogue of testosterone, works by acting as a potent and specific, competitive inhibitor of one of the two subtypes of 5α-reductase, specifically the type II isoenzyme. In other words, it binds to the enzyme and prevents endogenous substrates such as testosterone from being metabolized. 5α-reductase type I and type II are responsible for approximately one-third and two-thirds of systemic DHT production, respectively. Other 5a-reductase substrates include progesterone, androstenedione, epi-testosterone, cortisol, aldosterone, and deoxycorticosterone. The entire physiologic effect of their reduction is unknown, but likely related to their excretion or is itself physiologic. Beyond being a catalyst in the rate-limiting step in testosterone reduction, 5alpha-reductase enzyme isoforms I and II reduce progesterone to dihydroprogesterone (DHP) and deoxycorticosterone to dihydrodeoxycorticosterone (DHDOC). In vitro and animal models suggest subsequent 3alpha-reduction of DHT, DHP and DHDOC lead to steroid metabolites with effect on cerebral function by enhancing gamma-aminobutyric acid GABAergic inhibition. These neuroactive steroid derivatives enhance GABA at GABA(A) receptors and have anticonvulsant, antidepressant and anxiolytic effects, and also alter sexual and alcohol related behavior.5α-dihydrocortisol is present in the aqueous humor of the eye, is synthesized in the lens, and might help make the aqueous humor itself. Allopregnanolone and THDOC are neurosteroids, with the latter having effects on the susceptibility of animals to seizures. 5α-dihydroaldosterone is a potent antidiuretic agent, although different from aldosterone.
Source: http://en.wikipedia.org/wiki/Finasteride
Minoxidil : The mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil contains the nitric oxide chemical moiety and may act as a nitric oxide agonist. Similarly, minoxidil is a potassium channel opener, causing hyperpolarization of cell membranes. Minoxidil is less effective when there is a large area of hair loss. In addition, its effectiveness has largely been demonstrated in younger men who have experienced hair loss for less than 5 years. Minoxidil use is indicated for central (vertex) hair loss only.Minoxidil is also a vasodilator.[8] Hypothetically, by widening blood vessels and opening potassium channels, it allows more oxygen, blood, and nutrients to the follicle. This may cause follicles in the telogen phase to shed, which are then replaced by thicker hairs in a new anagen phase. Minoxidil is marketed under many trade names, including Avogain, Rogaine, Regaine, Lipogaine, Avacor Physician's Formulation, Kirkland, Tugain, Loniten (oral), Mintop, Amexidil, and Vanarex.
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