I changed my son's formula milk a week before sya mag 1 yr. old. From Nestogen, nagpalit ako S26 and wala naman naging prob. Pero better check with your baby's pedia baka kasi may milk na hindi hiyang baby mo. Like sa son ko, nagtry kami Nido pero nagkapantal sya ng marami kaya we opt for S26 as one of the options na binigay samin ng pedia.