Good to rotate both Eph and Clen over training days to help your receptors stay fresh, but i would only use either if i was going to compete, both stress the heart, more so the clen. Adding t3 at a low dose after 4 weeks increases the fat burning effect at the right time of the fat burning cycle as the receptors are beginning to get downgrade, and it saves having to up the dosage, well at least initially.