There are four key types of experimental studies used to gain evidence to support claims about cosmetic products: in vivo studies test products on volunteers to collect data on effectiveness; in vitro tests use artificial cell lines and models; ex vivo tests use harvested tissue; and in silico tests rely on computer simulations to predict effects without physical samples. Pragna Chakravarti has expertise in conducting clinical test reviews and claims substantiation to assist cosmetic companies.

1. The Four Key Types
of Experimental
Studies
Pragna Chakravarti

2. Introduction
• Pragna Chakravarti has extensive experience working as
a pharmaceutical chemist and is the president of
Pragna Chakravarti Consulting, an organization that
assists cosmetic companies with formulating and
marketing products. In this role, Pragna Chakravarti
offers a range of services to entrepreneurs and
established companies and has expertise in several
industry areas including conducting clinical test reviews
and providing claims substantiation support.
One of the methods used to gain evidence to support
claims about cosmetic products is to conduct
experimental studies. These studies include in vivo, in
vitro, ex vivo and in silico. Each of these methods is
described below.

3. Experimental Studies
• In vivo studies are used to collect evidence about how effective a
cosmetic product is. This study type involves testing the product
on volunteers under specific laboratory conditions for a defined
length of time. Specialized technology is used to gain information
about parameters such as sun protection, skin elasticity, and level
of hydration, among others.
In vitro tests are not conducted within living organisms, but
rather in artificial cell lines and models such as a human
epidermis which has been reconstructed. Ex vivo tests are carried
out in tissue that has been harvested, such as human hair that
has been cut or skin that has been explanted. Finally, in silico tests
rely on a computer simulation rather than a physical sample to
predict how a chemical compound might exert an effect on a
living organism.