How to Switch From a Soy- to Milk-Based Formula

Many parents begin giving their baby soy formula because their infant has reacted adversely to milk formula. Milk formula can cause some babies to spit up excessively, or get diarrhea or stomach aches. If your baby has been on soy formula and you want to switch your baby to milk formula, do so by gradually weaning the baby off soy. The weaning process takes three weeks.

Always consult your baby’s pediatrician before starting with milk formula to discuss both the benefits and risks that can come with switching types of formula.

Combine 1/4 milk formula with 3/4 soy formula for one week. Do not use more powder than the directions call for. Typically a 1/4-cup (four 1-ounce scoops) of powder is used in an 8-ounce bottle.

Increase the amount of milk after the first week. Combine 1/2 milk formula with 1/2 soy formula for week two.

Increase the amount of milk again after the second week. Combine 3/4 milk formula with 1/4 soy formula for week three.

Use a full milk formula after the third week.


Your baby may spit up a bit more when switching to milk. This is normal, however, your pediatrician should be consulted if it goes on for longer than two weeks after weaning.

Always store pre-mixed formula in the refrigerator to preserve freshness and nutrition. Dump any formula that has been in the refrigerator for longer than two days. Always dump any formula that is left in the bottle after feeding.

Do not give your baby regular dairy milk until he or she is a year old.

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