In Vivo

In vivo is Latin for “within the living” and refers to studies that affect and are tested on whole, living organisms, usually animals (including humans) and plants. In vivo studies include experiments performed in live animal models as well as human clinical trials. 

This is in contrast to in vitro studies on isolated biological molecules, protein, viruses, bacteria, tissues, organs, cells in culture, or dead organisms.[1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC175930/ 

Example of an In Vivo Study

Animal testing and human clinical trials are the main examples of in vivo research. Compounds and therapies are generally tested on animals bred specifically for research purposes. These include (but are not limited to):

  • Mice
  • Rats
  • Rabbits
  • Hamsters
  • Guinea pigs
  • Dogs
  • Primates

We need in vivo studies to evaluate the efficacy of different drugs and therapies within the context of an entire organism. For example, a new drug might work in a Petri dish or test tube on isolated cells or tissues, but not within the complex workings of the human body. 

Researchers might use in vivo studies to:[2]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895438/

  • Discover and test new drug formulations
  • Understand absorption, breakdown, efficacy, and side effects of certain drugs and treatments within a whole organism
  • Discover or deepen their knowledge of certain biological systems

Advantages Of In Vivo Experiments 

In vivo studies will almost always offer more specific and detailed results than in vitro. 

That’s because researchers can better evaluate the safety, efficacy, absorption, and toxicity of a drug or therapy in a complex (animal) model than in an isolated compound or tissue (in vitro). 

In fact, most drugs, therapies, supplements, and personal care products are only available to the public after rigorous in vivo studies (often performed on animals). However, plenty of substances go through human clinical trials, including most drugs and vaccines. 

Disadvantages Of In Vivo Experiments

While there are unmistakable advantages to in vivo experiments, there are also some major downfalls. 

In vivo studies in both animals and humans can cause extreme pain and distress, sparking ethical concerns. There’s also a problem of translatability when it comes to animal studies because of the vast physiological differences.

In vivo studies are also often more strict, expensive, and take longer to reach a clear consensus than in vitro research. 

In Vivo vs. Ex Vivo

Often confused with in vivo, ex vivo refers to experiments conducted on isolated cells, tissues, or organs in a controlled external environment. Cell cultures from biopsies are an example of ex vivo studies or observations.