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Specimen Atlas of Research Peptides81 plates · MIT
Side-by-side · Research reference

LivagenvsPT-141

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

AAnimal-StrongHUMAN-REVIEWED20/32 cited
BFDA-ApprovedHUMAN-REVIEWED13/41 cited
Livagen
Khavinson Bioregulator · Hepatoprotective Tetrapeptide
50%Dipeptidase inhibitionTimofeeva 2005
Oral / SQRoutes tested
LiverTarget tissueKhavinson 2001
Oral or SQ · Tissue-specific to liver
PT-141
MC4R Agonist · FDA-Approved (HSDD)
SQ · Abdomen / thigh · ≥45 min before sex

01Mechanism of Action

Parameter
Livagen
PT-141
Primary target
Hepatocyte protein synthesis machineryBrodskiĭ 2001
Melanocortin-4 receptor (MC4R) in hypothalamusSimerly 2023VYLEESI (bremelanotide injecti 2019
Pathway
Tissue-specific bioregulator → Hepatocyte stimulation → Protein synthesis normalizationBrodskiĭ 2001Khavinson 2001
MC4R agonism in paraventricular nucleus → autonomic + neuroendocrine sexual arousal pathwaysSimerly 2023
Downstream effect
Age-dependent enzyme normalization, hepatoprotection in fibrosis/hepatitis models, elevated protein synthesis in senescent hepatocytes
Increased sexual desire and arousal; central rather than peripheral mechanismClayton 2015
Feedback intact?
Origin
Directed chemical synthesis from amino acid analysis of liver polypeptide preparations (Ventvil)
Cyclic 7-AA peptide derived from α-MSH (agonist Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-OH cyclic)VYLEESI (bremelanotide injecti 2019
Antibody development

02Dosage Protocols

Parameter
Livagen
PT-141
Animal dose (oral)
Not specified in abstracts; 2-week administration protocolTimofeeva 2005
Per os administration in rats.
Duration (experimental)
2 weeks (enzyme study); up to 24 months (cell culture)Timofeeva 2005Brodskiĭ 2001
Route
Oral or subcutaneous
Resists peptidase hydrolysis, enabling oral bioavailability.Timofeeva 2005
Evidence basis
Animal models (rats, 1–24 months age); in vitro hepatocyte cultureTimofeeva 2005Brodskiĭ 2001Khavinson 2002
FDA-approved (HSDD pre-menopausal women)VYLEESI (bremelanotide injecti 2019Clayton 2015
Human data
None in provided literature
Standard dose
1.75 mg SQVYLEESI (bremelanotide injecti 2019
Single dose ≥45 min before anticipated sexual activity. Max 1 dose / 24 hr.
Frequency
PRN, max 8 doses / month
Lower / starter dose
1 mg (off-label)
Duration
PRN; reassess if no benefit after 8 doses
Reconstitution
Pre-filled commercial pen (Vyleesi). Research vial: bacteriostatic water.
Timing
≥45 min before sexual activity

04Side Effects & Safety

Parameter
Livagen
PT-141
Reported adverse effects
None documented in animal studies
Human safety data
No human trials in provided literature
Peptide hydrolysis
Weakly hydrolyzed; minimal breakdown by intestinal enzymesTimofeeva 2005
Nausea
Common (~40%); often transientVYLEESI (bremelanotide injecti 2019
Flushing
Common, transient
Injection site reaction
Erythema, mild pain
Headache
Common
Hyperpigmentation (focal)
Rare focal skin darkening; reversible after discontinuationVYLEESI (bremelanotide injecti 2019
Hypertension (transient)
Mean ↑6 mmHg systolic peaking ~4 h post-dose; resolves within 12 hVYLEESI (bremelanotide injecti 2019
Pregnancy / OB
Contraindicated
Cardiovascular disease
Use caution; transient BP rise
Absolute Contraindications
Livagen
PT-141
  • ·Uncontrolled hypertension
  • ·Known cardiovascular disease (caution)
  • ·Pregnancy
Relative Contraindications
Livagen
PT-141
  • ·Pre-existing hyperpigmentation disorders
  • ·MC4R-pathway-dependent psychiatric conditions

05Administration Protocol

Parameter
Livagen
PT-141
1. Route selection
Oral administration supported by peptidase resistance. Subcutaneous route used in organotypic culture experiments.Timofeeva 2005Khavinson 2001
Vyleesi: pre-filled auto-injector. Research vial: 2 mL bacteriostatic water per 10 mg → 5 mg/mL.
2. Timing
No specific timing documented. Two-week protocols used in animal models with daily administration.Timofeeva 2005
SQ — abdomen or thigh.
3. Age-dependent response
Elderly individuals may exhibit different enzyme normalization patterns than younger cohorts, based on rat age-stratified findings.Timofeeva 2005
≥45 min before sexual activity for peak effect. Effect persists ~6–8 h.
4. Storage
Vyleesi: room temp ≤30 °C. Research vial: refrigerate after reconstitution.
5. Needle
Auto-injector (Vyleesi) or 29–31G, 4–8 mm insulin syringe.