📖Complete GuideUpdated 2026🔬Evidence-Based

RU58841 Guide

Topical Anti-Androgen for Hair Loss 2026

Complete guide to RU58841 — the research topical anti-androgen that blocks DHT at scalp androgen receptors.

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ACTIVE MEDICATIONS
Ru58841B12
RU58841
🔥 14
2
days away
Thursday · 7.5mg
Medication Supply
Ru58841
6.2 / 10 mg · Vial
~42 days left · Mar 15
B12
4.4 / 5 ml · Vial
~88 days left · May 8
Retatrutide
1.2 / 5 mg · Vial
~6 days left · refill soon
Medication Levels
7 Days2 Weeks1 Month90 Days
CURRENT LEVEL
5.42mg
Mar 6
Today
ACTIVE MEDICATIONS
Ru58841Retatrutide
0mg2.7mg5.4mg
18
Total Injections
💉 All time
122/78
Average BP
🩺 mmHg
8.4
Avg Mood
😊 /10
Health Chart
1mAll
218.6lb
↓ 8.4 lb · 3.7%
WeightInjectionsBPMood
2282222162102277.5mg7.5mg4mg10mg218
Feb 6Feb 14Feb 22Mar 2Today
Photos
12 photos · 2w streak
Week 1
Week 7
Today
Scheduled Reminders
Weight
Due today
Mood
Done
Blood Pressure
Tomorrow
Body Measurements
In 3 days
Dashboard
Your complete health overview in one place
🔥
14-day streak
Logged 18 of 18 scheduled shots
Next Shot Reminder
ACTIVE MEDICATIONS
Ru58841B12
RU58841
🔥 14
2
days away
Thursday · 7.5mg
Medication Supply
Ru58841
6.2 / 10 mg · Vial
~42 days left · Mar 15
B12
4.4 / 5 ml · Vial
~88 days left · May 8
Retatrutide
1.2 / 5 mg · Vial
~6 days left · refill soon
Medication Levels
7 Days2 Weeks1 Month90 Days
CURRENT LEVEL
5.42mg
Mar 6
Today
ACTIVE MEDICATIONS
Ru58841Retatrutide
0mg2.7mg5.4mg
18
Total Injections
💉 All time
122/78
Average BP
🩺 mmHg
8.4
Avg Mood
😊 /10
Health Chart
1mAll
218.6lb
↓ 8.4 lb · 3.7%
WeightInjectionsBPMood
2282222162102277.5mg7.5mg4mg10mg218
Feb 6Feb 14Feb 22Mar 2Today
Photos
12 photos · 2w streak
Week 1
Week 7
Today
Scheduled Reminders
Weight
Due today
Mood
Done
Blood Pressure
Tomorrow
Body Measurements
In 3 days
01BACKGROUND

Topical Anti-Androgen: DHT Blocker at the Scalp (Research Use 2026)

RU58841 is a research topical anti-androgen applied directly to the scalp that locally blocks dihydrotestosterone (DHT) at androgen receptors in hair follicles — halting androgenetic alopecia progression without the systemic side effects of finasteride or dutasteride.

02DEEP DIVE

What Is RU58841?

RU58841 (PSK-3841) is a non-steroidal anti-androgen originally developed for topical application in the 1980s-90s. It functions as a high-affinity androgen receptor (AR) antagonist — binding scalp AR with ~3-4x the affinity of DHT without activating the receptor. This competitive inhibition prevents DHT from signaling hair follicle miniaturization. Unlike systemic anti-androgens (finasteride, dutasteride), which reduce serum DHT levels and carry sexual side effects, RU58841 acts locally at the scalp with minimal systemic exposure. It is a research chemical — not FDA approved — but is widely used in the hair loss community as a hair-preserving adjunct.

Most widely used topical concentration in research protocols

Minimal systemic DHT suppression — primarily scalp-level action

Maintenance of hair density requires consistent long-term use

03MECHANICS

Key Biohacking Mechanics

1
Binds scalp AR with higher affinity than DHT
2
Competitive blockade — no receptor activation (no androgenic effect)
3
Prevents DHT-mediated follicle miniaturization signaling
4
Preserves existing terminal hair follicle function
5
Undergoes rapid photolytic/metabolic breakdown
6
Minimal systemic absorption compared to finasteride
7
Does not suppress blood DHT levels significantly
8
Preserves male hormonal profile in most users
9
Macaque hair regrowth studies show strong efficacy
10
Shown to arrest progression rates comparable to finasteride in some models
11
No direct large-scale human RCT data (research compound)
12
Anecdotally: widely reported hair preservation in NW2-NW4 MPB
13
Minoxidil: complementary (minoxidil = growth stimulation; RU58841 = DHT blockade)
14
Microneedling: improves topical penetration to follicle level
15
Ketoconazole shampoo: reduces scalp inflammation
16
Finasteride stack used by some — systemic + local coverage
04WHAT TO TRACK

Dosing Protocol

01
🔬
Beginner Protocol
Start at 2.5% for 4 weeks. Apply 1mL to dry scalp nightly. Massage for 30 seconds into thinning zones. Allow to dry before pillow contact
02
🔬
Standard Protocol
5% solution — 1mL per application. Once daily, preferably PM. Stack with minoxidil AM application. Track progression with monthly photos in Shotlee
03
📱
Monitoring Approach
Photograph hairline and crown monthly. Track any systemic side effects (rare but monitor). Check serum DHT if concerned (typically unchanged). Cycle logs in Shotlee for long-term data
05WHAT TO TRACK

Side Effects & Safety

01
Advantages Over Systemic AADs
No sexual side effects (unlike finasteride/dutasteride). No systemic DHT suppression. No impact on PSA, fertility or libido typically. Reversible — discontinue and androgen receptors normalize
02
🔬
Reported Concerns
Scalp irritation at high concentrations. Contact dermatitis in sensitive individuals. Some users report mild systemic sides at very high doses. Degradation if improperly stored (heat-sensitive compoun
06WHAT TO TRACK

Vital Protocol FAQs

01
⚖️
Does RU58841 stop hair loss?
Research data and community reports suggest RU58841 arrests androgenetic alopecia progression in most users who apply it consistently. Animal studies show strong AR antagonism at the follicle level. A
02
🔬
Is RU58841 safer than finasteride?
RU58841\'s primary advantage over finasteride is avoiding systemic DHT suppression — which is responsible for finasteride\'s sexual side effects (impotence, reduced libido, gynecomastia in some men).
03
🧬
How do I track my RU58841 protocol?
Shotlee supports tracking research compound protocols. Log daily applications with dose, time, and scalp area. Use the notes field to document monthly hair progression assessments. Set a monthly remin
07FAQ

Guide FAQs

Complete guide to RU58841 — the research topical anti-androgen that blocks DHT at scalp androgen receptors.

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📚References & sources

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