You technically can, but it is not a recommended practice. Instead, it's best to only add one additive to a respective fluid type (oil, fuel. etc) per service interval. Additives should be used according to the instructions on the manufacturer's packaging.
The best results come from using different oil additives on separate oil change intervals.
To get shopping for the correct additives for your next oil change, head over to fcpeuro.com and enter your vehicle information into the fitment selector
Once your car is added to the selector, there are a couple of important ways that we advise correct fitment.
The first is the "fitment indicator" shown on the Product Page after selecting a part. This box is below the "add to cart button" and has two states. It will either say " Yes this part fits" or "Part may not fit, click to verify".
Sometimes the green box will be accompanied by extra fitment notes. These notes may be independent of the information gathered by the vehicle selector. IE: VIN-specific options, need to be taken into account when determining overall fitment.