The study is a two part study, designed to validate safety results from the Phase 1 PP405-001 trial while also characterizing longer term safety and PK. Part 1 of the trial is the randomized controlled portion that will focus on safety and PK following 28 days of blinded treatment administration with either PP405 or vehicle control. Part 2 of the trial is an open-label extension that will validate the results of Part 1 with 3 months of treatment administration.

Safety, Pharmacokinetics, and Efficacy Study of PP405 in subjects with Androgenetic Alopecia.

Inclusion Criteria:

1. Male or female subjects aged 18 to 55 years.
2. Able and willing to provide written informed consent.
3. Males must have an AGA modified Norwood-Hamilton Classification score of Type III vertex, Type IV or Type V. Females must have a Savin classification score of I-2, I-3 or I-4.
4. Agree to comply with protocol procedures

Exclusion Criteria:

1. Concomitant diagnosis of non-AGA forms of alopecia.
2. Use of other hair loss treatments within periods specified in protocol.
3. Use of excluded medications as specified in protocol.
4. Diagnosis of other medical conditions as specified in protocol.
5. Any disease or medical condition that, in the opinion of the Investigator, would prevent the subject from participating in the study or might confound study results.