A more thorough explanation:

The Two-Controlled-Studies Standard is a requirement set by the Federal Trade Commission (FTC) for makers of over-the-counter painkillers. It states that before a maker can advertise that their product is better or has fewer side effects than another brand, they must verify the claim in two scientifically controlled studies.

For example, if a company wants to claim that their painkiller is more effective than a competitor's, they must conduct two studies that show their product is indeed more effective. These studies must be conducted in a controlled environment, meaning that all variables are kept constant except for the painkiller being tested.

Another example would be if a company wants to claim that their painkiller has fewer side effects than a competitor's. They must conduct two studies that show their product has fewer side effects. These studies must also be conducted in a controlled environment, with all variables kept constant except for the painkiller being tested.

The Two-Controlled-Studies Standard is in place to protect consumers from false advertising claims. By requiring scientific evidence to back up advertising claims, the FTC ensures that consumers can make informed decisions about the products they purchase.