Allergy/intolerant? First you need to separate allergy from intolerance. Allergy testing by prick test (painless piece of plastic on back) will determine if it is allergy or intolerance. If you baby has a true allergy, then soy in any form can be a problem. To change the source of protein whether it is cow's milk based, elemental or other form, allergy testing can help determine what would be safe.