The Influence of Skin Structure on Permeability: An Intersite and Interspecies Comparison with Hydrophilic Penetrants

Topical finasteride may have higher systemic absorption and lower efficacy when using a Propylene Glycol/Ethanol formulation compared to the hydroxypropyl chitosan (HPCH) formulation. The safety profile of topical finasteride relies heavily on the HPCH formulation, and using standard solutions might lead to different pharmacokinetics.

The conversation discusses the potential benefits of creating a hydrophobic version of finasteride to reduce systemic side effects while maintaining scalp health. It compares this idea to fluridil, which is designed to be hydrophobic and has less systemic absorption.

The conversation discusses how the absorption rate of topical finasteride varies and is not equivalent to its oral form, with only a small percentage reaching the scalp. It also mentions that minoxidil in high concentrations is used topically because only a small amount is absorbed.

The conversation discusses using high molecular weight hyaluronic acid after microneedling to form a protective barrier, though it's considered expensive and offers marginal improvement. Users share experiences with different microneedling tools like derma rollers, dermastamps, and Dr. Pen, with some opting not to use any products on the scalp.

Topical dutasteride may have limited absorption due to its higher molecular mass compared to finasteride, potentially affecting its efficacy in suppressing DHT locally. Microneedling might enhance dutasteride absorption, possibly offering stronger local DHT suppression with fewer systemic effects.

Topical finasteride with hydroxypropyl chitosan shows significantly less serum absorption and minimal DHT reduction compared to oral finasteride. Users need the specific chitosan formulation to avoid side effects seen with regular ethanol+PG solutions.