There are several baby formulas that are structurally similar to human breast milk. Here are some of the closest formulas to breast milk based on the search results:

• Enfamil Enspire: This formula is the closest to breast milk, thanks to the inclusion of proteins.
• Similac 360 Total Care: This formula contains 5 HMO prebiotics structurally identical to those in breast milk.
• Bobbie Organic Formula: This formula is EU-inspired and US-crafted, and it is a tried and true favorite of The Everymom.

Its important to note that there is no one formula that is universally best for all babies, and it may take some time to find what works best for you and your baby. When choosing a formula, its important to consider the ingredients, nutritional value, and ease of preparation. Formulas that contain whey protein, lactose, and a blend of vegetable oils are often considered the closest to breast milk.