Commercial plant-based infant formulas sold in the United States are nutritionally adequate for babies. They must meet the same FDA nutrient requirements as cow’s milk formulas before reaching store shelves. That said, “plant-based formula” covers several different products, from soy to hydrolyzed rice to newer pea protein options, and each comes with its own profile of benefits and considerations worth understanding before you choose one.
What Counts as Plant-Based Formula
Plant-based infant formulas use protein sourced from plants rather than cow’s milk. The most common type by far is soy-based formula, which has been used for decades. Hydrolyzed rice protein formulas have been widely available in Europe for years and are gaining traction elsewhere. Newer entries use pea protein isolate as their primary protein source. All of these are distinct from plant milks like almond, oat, or coconut milk, which are not formulas, are not nutritionally complete, and should never be used as a substitute for breast milk or infant formula.
Every infant formula sold in the U.S., regardless of its protein source, must meet the nutrient specifications in FDA regulations (21 CFR 107.100). Manufacturers are required to test each production batch for every required nutrient before distribution. This means a properly manufactured soy or rice formula delivers the same baseline of calories, vitamins, minerals, and macronutrients that a cow’s milk formula does.
Soy Formula: The Most Studied Option
Soy formula is the plant-based option with the longest track record. It supports normal growth in healthy, full-term infants and is widely used when families want to avoid animal-derived ingredients or when a baby doesn’t tolerate cow’s milk well.
The main point of debate around soy formula involves compounds called isoflavones, which have a weak estrogen-like activity in the body. Infants on soy formula are exposed to 5.7 to 11.9 milligrams of isoflavones per kilogram of body weight during the first four months of life. On a body-weight basis, that’s 6 to 11 times higher than what an adult eating a soy-rich diet would consume. These isoflavones are roughly 100 to 1,000 times less potent than the body’s own estrogen, but the high relative exposure in infants has prompted ongoing research into whether it affects reproductive or endocrine development later in life. So far, only one study has followed soy-fed infants all the way to adulthood to look at reproductive health outcomes, which makes it difficult to draw firm conclusions either way.
For babies with a confirmed cow’s milk allergy, soy formula works for most but not all. About 10% to 14% of infants allergic to cow’s milk also react to soy. European and international allergy guidelines generally recommend against soy formula for babies under 6 months with cow’s milk allergy due to that cross-reactivity risk, though it may be appropriate after 6 months for allergies driven by a specific immune pathway (IgE-mediated).
Hydrolyzed Rice Formula
Rice-based infant formulas use rice protein that has been broken down (hydrolyzed) into smaller fragments, which makes it easier to digest and far less likely to trigger an allergic response. In a review of 11 clinical trials, hydrolyzed rice formula supported normal growth in healthy children and catch-up growth in children with cow’s milk allergy. A study of 100 infants with confirmed cow’s milk allergy found that while 4% showed a positive skin test to rice protein, none actually developed symptoms, likely because the hydrolysis process alters the protein enough to prevent an immune reaction.
In a head-to-head trial comparing hydrolyzed rice formula with extensively hydrolyzed cow’s milk formula in 92 infants with moderate to severe cow’s milk allergy, all infants tolerated the rice option well, while one child reacted to the cow’s milk-based hydrolysate. Calcium and magnesium blood levels in infants on rice formula have been comparable to those on soy formula in the studies conducted so far, though researchers note that no long-term studies have specifically measured bone density or fracture rates in these children.
One consideration with any rice-based product for infants is arsenic. Rice naturally absorbs inorganic arsenic from soil and water. The FDA has set an action level of 100 parts per billion for inorganic arsenic in infant rice cereals. Testing showed average arsenic levels in infant rice cereals dropped from about 117 ppb in 2011-2013 to 85 ppb in 2018, suggesting industry reformulation is working. Hydrolyzed rice protein formula goes through extensive processing that differs from whole-grain rice cereal, but it’s worth being aware of arsenic as a background concern with rice-based infant products.
Pea Protein Formula
Pea protein is the newest plant source used in infant and pediatric formulas. The yellow pea protein isolate used in these products scores a 1.0 on the protein digestibility scale (PDCAAS), which is the highest possible score and matches the quality rating of cow’s milk protein. It contains all nine essential amino acids in proportions that meet requirements for young children, with added L-cysteine to round out the profile. Pea protein also has naturally occurring arginine, an amino acid important for cell growth that becomes especially critical during illness or stress.
From a taste perspective, pea protein has natural emulsification properties that make it less bitter than many other plant proteins, which can help with acceptance. The processing method avoids chemical solvents, preserving the protein’s structure and flavor. Early clinical data on pea-based complete nutrition formulas show good tolerance when children transition from other hypoallergenic products, though this is still a newer category with less long-term data than soy or rice formulas.
When Plant-Based Formula Makes Sense
The clearest medical reason to use a plant-based formula is cow’s milk protein allergy. For families navigating this diagnosis, the choice typically comes down to cost, availability, and how severe the allergy is. Extensively hydrolyzed cow’s milk formulas are the standard first-line option, but they’re expensive and often taste bitter. Soy formula is more affordable and more palatable, making it a practical alternative for many families, particularly for babies over 6 months with IgE-mediated allergy. Hydrolyzed rice formula offers another well-tolerated choice with essentially no cross-reactivity in clinical studies.
Galactosemia, a rare metabolic condition where babies cannot break down the sugar galactose found in all mammalian milks, is another clear indication. Soy formula contains no galactose and is the standard recommendation for these infants. Families who follow a vegan diet or who have religious or cultural reasons to avoid animal products also commonly choose plant-based formulas for their infants.
Plant Milks Are Not Formula
This distinction is critical. Store-bought almond milk, oat milk, coconut milk, and similar beverages are not designed for infants and can cause serious harm if used as a primary food source. These products often lack adequate calories, protein, calcium, and vitamin D. Babies fed homemade or non-formula plant milks can develop dangerous electrolyte imbalances, severe vitamin D deficiency, and even rickets, a disorder that weakens and softens bones. Homemade infant formula recipes found online, whether based on goat’s milk, nut milks, or other ingredients, are not regulated, frequently fail to meet infant nutritional needs, and have been linked to life-threatening outcomes.
The only safe options for infants who are not breastfed are commercially manufactured infant formulas that meet FDA standards, whether those formulas are cow’s milk-based, soy-based, or made from another approved protein source.
Choosing the Right Formula
If your baby is healthy, full-term, and has no allergies, both cow’s milk and soy formulas will support normal growth. The choice is largely one of preference. If your baby has a diagnosed cow’s milk allergy, the severity of the allergy and your baby’s age will guide which plant-based option fits best. For mild to moderate allergies in babies over 6 months, soy formula is a reasonable and affordable choice. For more severe allergies or younger infants, hydrolyzed rice formula or amino acid-based formula (which is synthetic rather than plant or animal-derived) provides the lowest risk of reaction.
Whichever plant-based formula you choose, look for products specifically labeled as infant formula rather than toddler drinks or nutritional beverages. Only products meeting the FDA’s infant formula regulations are required to contain the full spectrum of nutrients a baby needs during the first year of life.