What is the difference in the onset time and half-life of erections between sildenafil and tadalafil

Drugs need to reach a certain blood drug concentration in the body to exert therapeutic effects. The time required to reach the maximum blood drug concentration peak is called the peak time (Tmax); The time when the blood concentration of a drug decreases by half is called the half-life. It can be seen that sildenafil takes effect quickly, but the duration of action is short. It is recommended to take it 1 hour before sexual activity for the best therapeutic effect; Tadalafil takes effect slowly, and it is recommended to take it 2 hours before sexual activity for the best therapeutic effect. However, due to its long duration of action, it is also known as "long-acting Viagra".