If you had low sexual desire before starting effexor, the symptoms could just be returning.If not, its as you say, which is a mild withdrawal symptom that could improve over time.You could try taking HALF the dose every day(which would require different pills since they are caps)Discuss this with your doctor and he will prob. let you come get samples to try.(if you and he agree that a taper trial is appropriate.)An even slower way to taper would be to take your present dose one day and half that dose next for 2 weeks before taking half dose daily.