research Thymic Peptides Differentially Modulate Human Hair Follicle Growth 7 citations, March 2012 in “Journal of Investigative Dermatology” Some thymic peptides can increase human hair growth, while others may inhibit it.
research Changes in Growth and Distribution of Hair Associated with Psychotropic Drug Use 6 citations, October 1997 in “CNS Drugs” Psychotropic drugs can cause hair loss or excessive hair growth.