The 2020 USDA-HHS Dietary Guidelines Advisory Committee Report and other prominent medical associations (NIH, AAP, AAAAI) recommend starting babies as early as 4 months of age with food allergen introduction.
We recommend starting the Stage 1 introduction, and Stage 2 for continued exposure together anytime between 4 - 12 months of age. You should sustain exposure to Stage 2 for least 6 months.
Stage 3 is designed as the next step from Stage 2, and expands allergen exposure from 3 to 9 allergens including tree nuts, sesame, wheat and soy. However, if your baby hasn't started allergen introduction, but is already eating solid foods, feel free to start with Stage 3.