I'm taking synthroid (thyroxine) med once a day and i started taking herbalife would that in interfere?

No: No- there is no interaction.

Food interactions: To my knowledge, foods like dietary fiber, soybean flower, cottonseed meal, walnuts, calcium and calcium-fortified juices can affect the absorption of levothyroxin Syntroid & interfere with maintaining steady blood levels. So take these foods at the same time each day; and, if possible, avoid taking them within several hours of taking your levothyroxin. Hope that helps.