fluctuating as all esters are for stable hormone levels go by the half-life of the hormone your injecting ,Half-life of cyp is about 12 days, So considering the half-life For more stable blood levels and to keep blood levels high inject at or around half of the half-life of the hormone. With cyp about every 4-5 days, Injecting right at the half-life would let blood levels drop to low. Like everyone stated 2 injects every week will work with cypioante for most and BB purposes.