Hi, thanks for asking in Healthcare Magic. Vynase is Lisdexamphetamine known for its mood elevating properties. It is also an appetite suppressant and reduces weight and that is why you are losing weight. Although delay in periods is most commonly due to hormonal imbalance or illness, diet also plays a major role. Rapid loss of weight can interfere with menstrual cycle. It is not the quantity but quality of diet that is needed to balance the hormonal levels. A good nutritious diet plays a vital role in regularizing the menstrual cycle. Nutritional deficiency can lead to anemia and vitamin deficiency which can further delay the period. As such Vynase has no direct action in delaying the period but can indirectly delay the period by interfering with appetite and reducing weight. You should consult your treating Dr about reducing the dose of Vynase or should use an appetite stimulant to improve your appetite and weight. Further, add soy protein, vegetables, milk, egg , meat and plenty of greens in your diet. I hope this is helpful to you.