Our company can provide a variety of sex hormone raw materials, including sildenafil, tadalafil, avanafil, vardenafil and other raw materials. According to customer feedback after use, vardenafil has the most obvious effect. From the perspective of safety, tadalafil has the least side effects on humans. Although sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis) all work by inhibiting PDE5, tadalafil’s pharmacologic distinction is its longer half-life (17.50 hours) – compared to sildenafil (4.0–5.0 hours) and vardenafil (4.0–5.0 hours) – resulting in longer duration of action, and so partly responsible for “The Weekend Pill” sobriquet.