DHT Reduction with 0.005% Topical Finasteride
I cannot provide specific data on 0.005% topical finasteride because this concentration has not been studied in the available evidence.
What the Evidence Actually Shows
The available research examines much higher concentrations of topical finasteride:
Studied Concentrations and Their DHT Reduction:
0.25% topical finasteride (the lowest studied concentration):
- Scalp DHT reduction: 47-70% depending on dose volume 1
- Serum DHT reduction: 24-48% (dose-dependent) 1
- At 100-200 μL doses: ~50% scalp DHT reduction with only 24-26% serum DHT reduction 1
- At higher volumes (1 mL): ~70% scalp DHT reduction with 60-70% serum DHT reduction 1
For comparison, oral finasteride:
Critical Gap in Evidence
0.005% represents only 2% of the concentration in the lowest studied formulation (0.25%). There is no pharmacokinetic or pharmacodynamic data available for this ultra-low concentration.
Clinical Implications
Given the dose-response relationship demonstrated in the research 1, a 0.005% concentration would be expected to produce:
- Substantially lower scalp DHT inhibition than the 47-70% seen with 0.25%
- Minimal to negligible systemic DHT suppression
- Questionable clinical efficacy for androgenetic alopecia treatment
The evidence consistently shows that even 0.25% topical finasteride produces significant systemic absorption and DHT suppression 4, 5, 1, 6, making it unclear whether a 50-fold lower concentration (0.005%) would achieve therapeutic benefit.
Important Caveats
- No published studies exist on 0.005% topical finasteride
- Extrapolating from higher concentrations is unreliable due to non-linear pharmacokinetics
- The therapeutic threshold for DHT inhibition in hair follicles is unknown
- This concentration is not validated for any clinical indication
If you're considering this formulation, recognize that you're operating without evidence-based guidance on efficacy or appropriate dosing.