Clinical Research Glossary

additive effect additive effect


The combined effect when two or more things are used together.

Example of additive effect in a sentence

The additive effect of a combination drug is the sum of the effects of each drug acting alone.

More Info

For example, two vaccines may be combined into one shot because they do not interfere with each other and will still each have the same effect as if they were given as two separate shots.

So an additive effect means that 1+1 = 2

Other info to think about when joining a study

You may hear the words “additive effect” being used if you are part of a study that is studying two or more treatments being taken together.

You may want to find out more about why the two treatments are being given together and what the hoped effect could be.

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