RU58841 — evidence

Studies and documents

1. CLINICAL TRIAL2026Single-dose human metabolism and excretion study

   Investigation into the metabolism and elimination behavior of RU 58841, and its influence on the steroid profile in humans

   Okutan A, Krug O, Fußhöller G, Piper T, Thevis M · Biomedical Chromatography

   Population

   Healthy male volunteers

   Sample

   n = 6

   Objective

   To characterise the human metabolism of RU58841 and assess systemic exposure after topical application.

   Endpoint investigated

   Metabolites in urine, parent drug and metabolites in dried blood spots, and steroid-profile parameters

   Study design

   Phase

   Not applicable (pharmacokinetic study)

   Duration

   Single application with dried-blood-spot and urine sampling

   Intervention, as the source describes it

   One topical application of an RU58841-containing hair treatment product, as reported

   This describes the published study design. It is not a usage or dosing recommendation.

   After a single topical application in six men, five RU58841 metabolites were detected in urine and both parent drug and an oxidised metabolite were detected in dried blood spots. The authors describe this as considerable systemic exposure. The steroid profile used in doping controls was not affected.

   Limitations. Six participants, one dose and no hair-growth endpoint. The study establishes metabolism and systemic exposure, not efficacy or long-term safety, and the commercial hair-treatment product used is not a pharmaceutical standard.

   DOI 10.1002/bmc.70602 · Okutan et al., Biomed Chromatogr (2026) — PubMed 42615108 · Reviewed 13 November 2026

2. CLINICAL TRIAL2005Multicentre, double-blind, randomised, vehicle-controlled trial (registry record)

   Hair regrowth with topical PSK 3841 2.5% and 5% in male androgenetic alopecia

   ProStrakan Pharmaceuticals · ISRCTN registry

   Population

   Men aged 18–50 with androgenetic alopecia, Norwood-Hamilton III or greater

   Objective

   To estimate hair regrowth with two concentrations of topical PSK 3841 in men with androgenetic alopecia.

   Endpoint investigated

   Quantitative hair regrowth, safety and tolerability

   Study design

   Phase

   Not specified in the registry record

   Duration

   6 months

   Intervention, as the source describes it

   PSK 3841 solution at 2.5% or 5%, applied once daily, compared with vehicle

   Comparator

   Vehicle

   Primary endpoint

   Quantitative estimation of hair regrowth

   This describes the published study design. It is not a usage or dosing recommendation.

   The registry record describes a six-month, multicentre, double-blind, vehicle-controlled study of 2.5% and 5% PSK 3841 applied once daily, with hair regrowth as the objective. The study is marked completed, with a completion date in 2003; no results are posted.

   Limitations. Registry record only. No published efficacy or safety results were identified. A completed trial with no posted result cannot support a claim that RU58841 regrows hair.

   DOI 10.1186/ISRCTN71083772 · ISRCTN — PSK-3841 hair-regrowth study (ISRCTN71083772) · Reviewed 13 November 2026

3. CLINICAL TRIAL2005Double-blind, randomised, vehicle-controlled safety and tolerability study (registry record)

   Safety and tolerance of topical PSK 3841 5% in men with androgenetic alopecia

   ProStrakan Pharmaceuticals · ISRCTN registry

   Population

   Healthy Caucasian men aged 18–50 with androgenetic alopecia

   Objective

   To assess the systemic and local safety and tolerance of topical PSK 3841, the research code for RU58841, in men with androgenetic alopecia.

   Endpoint investigated

   Safety and tolerability, pharmacodynamic endocrine profile and pharmacokinetics

   Study design

   Phase

   Not specified in the registry record

   Duration

   4 weeks

   Intervention, as the source describes it

   5% PSK 3841 solution or vehicle applied to the scalp twice daily

   Comparator

   Vehicle (70% ethanol)

   Primary endpoint

   Systemic and local safety and tolerability, including gonadotropins and steroids

   This describes the published study design. It is not a usage or dosing recommendation.

   The registry record describes a four-week, double-blind, vehicle-controlled study of 5% PSK 3841 applied twice daily. The study is marked completed; no results are posted in the record.

   Limitations. Registry record only. No published results were identified, so the study provides no efficacy estimate and no usable human safety conclusion beyond the fact that it was conducted.

   DOI 10.1186/ISRCTN49873657 · ISRCTN — PSK-3841 safety study (ISRCTN49873657) · Reviewed 13 November 2026