Dr. Catherine Mwangi is a passionate harm reduction advocate for women who use drugs in Kenya. She has extensive experience working with people who use drugs at the community and national level. While working at the community level she led the rolling out of harm reduction interventions in Kenya including the needle and syringe program, medically assisted therapy(MAT) and initial community exploratory survey for establishing magnitude of hepatitis disease among people who use drugs. At the national level she developed the standard operating procedures for MAT and the first HIV peer education manual for people who use drugs as well as a specific module on women who use drugs. She is an advocate of the peer to peer approach and has empowered many peers in the community of people who use drugs. Her PhD work focused on women who use drugs, HIV and mental health. It was one of the first PhD in the area of harm reduction in Kenya where drug use is criminalised affecting tertiary education acceptance such as a study.