Consumer campaign group Which? has compared different formulas, and says the core nutrients "are very similar".
"Some baby-formula manufacturers increasingly market their product as superior in quality, or containing extra or special ingredients," it said in its comparison.
"But such marketing claims should be treated with scepticism.
"This is because all infant formula sold in the UK is legally required to meet the same standards, so all will meet your baby's nutritional needs - irrespective of brand, price or claims about ingredients."