While there are many causes for hair loss, from fungal infections, to stress and malnutrition, the most common cause of hair loss in men is still androgenetic in nature (due to DHT). The effect of DHT (Dihydrotestosterone) on hair loss may be reduced by taking DHT blockers, such as finasteride and dutasteride. These medications may only be used by men. For topical application, minoxidil remains the most effective treatment. Although the actual cause is not fully known, it has been shown to stimulate vasodilation and this increase the blood flow which in turn helps to supply more oxygen, blood, and nutrients to the follicle. Low level laser treatments (LLLT) have also been shown to improve the hair condition by stimulating the small hairs (vellus hair) to thicker hair (terminal hair) for some individuals. These treatments are found to be more effective for younger men and over the vertex area. However, continuous treatment is required.