Oh yeah--the "grower" designation is confusing, because the "starter" is also called "grower." Then there is "grower/finisher," which is what most people mean by "grower." There are two chief differences: Starter comes in a medicated version, whereas I've never seen the "grower/finisher" medicated. But I used unmedicated for both. The other main difference is protein--the starter contains more, to promote strong early growth. The grower/finisher has less, to slow growth in size in favor of growth in strength/health.