Side-by-side · Research reference
GHRP-2vsThymosin α-1
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 2Reviewed15/42 cited
BPhase 3Reviewed8/39 cited
GHRP-2
Hexapeptide GHRP · Phase 2 (clinical diagnostic)
SQ · Multiple sites · 1–3×/day
Thymosin α-1
Immune modulator · Approved (some countries)
SQ · 2× weekly · 6+ months for chronic indications
01Mechanism of Action
Parameter
GHRP-2
Thymosin α-1
Primary target
Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990
Toll-like receptor 9 (TLR9) + T-cell maturation pathwayCamerini 2001
Pathway
GHS-R1a → Gαq → Ca²⁺ → GH vesicle exocytosisBowers 2002
TLR9 activation → ↑ IFN-α + IL-2 + IFN-γ → enhanced T-cell function + dendritic cell maturationIyer 2007
Downstream effect
Strong GH pulse + IGF-1 elevation; appetite increase via ghrelin agonismBowers 2002
Restored T-cell function, improved viral clearance, anti-tumour adjuvant effectsIyer 2007
Feedback intact?
Yes, with somatostatin feedback active
—
Origin
Synthetic hexapeptide; developed by Bowers/Tulane group in the 1980sBowers 1990
Synthetic 28-AA peptide identical to natural Tα-1 isolated from thymus extractCamerini 2001
Antibody development
—
—
02Dosage Protocols
Parameter
GHRP-2
Thymosin α-1
Frequency
1–3× per day
2× weekly (Mon/Thu typical)
Lower / starter dose
50 mcg per dose
0.8 mg per injection
Evidence basis
Phase 2 + clinical diagnostic useBowers 1990
Phase 3 + approved (35+ countries as Zadaxin)Iyer 2007
Duration
8–12 weeks on / 4 off (anecdotal)
6–12 months for chronic indications
Reconstitution
Bacteriostatic water
Sterile water for injection per vial label
Timing
Pre-sleep + fasted preferred
No specific time
04Side Effects & Safety
Parameter
GHRP-2
Thymosin α-1
Prolactin elevation
Mild but measurable
—
Hunger
Strong appetite increase
—
Injection site reaction
Mild erythema
Erythema, mild discomfort
IGF-1 elevation
Strong; monitor with chronic high-dose use
—
Cancer risk
Contraindicated in active malignancy
No signal — used as adjuvant in oncology
Pregnancy / OB
Avoid
Avoid
GI symptoms
—
Rare nausea
Fatigue
—
Common during initial weeks
Fever / flu-like
—
Mild interferon-like response possible
Autoimmune
—
Theoretical risk; caution in active autoimmune disease
Absolute Contraindications
GHRP-2
- ·Active malignancy
- ·Pregnancy / breastfeeding
Thymosin α-1
- ·Pregnancy / breastfeeding
- ·Hypersensitivity to peptide
- ·Concurrent immunosuppressant therapy (transplant patients)
Relative Contraindications
GHRP-2
- ·Untreated diabetes
Thymosin α-1
- ·Active autoimmune disease
- ·Severe immunocompromised state without supervision
05Administration Protocol
Parameter
GHRP-2
Thymosin α-1
1. Reconstitution
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.
Add 1 mL sterile water per 1.6 mg vial → 1.6 mg/mL.
2. Injection site
SQ — abdomen or thigh. Rotate sites.
SQ — abdomen, thigh, or upper arm. Rotate sites.
3. Timing
Pre-sleep + fasted preferred.
2× weekly, e.g. Monday + Thursday.
4. Storage
Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.
Lyophilised: refrigerate. Reconstituted: refrigerate, use within 24 h.
5. Needle
29–31G, 4–8 mm insulin syringe.
27–31G, 4–8 mm insulin syringe.
06Stack Synergy
GHRP-2
+ CJC-1295 (no DAC)
StrongGHRP-2 + CJC-1295-no-DAC is a higher-amplitude alternative to the ipamorelin + CJC-1295 stack. GHRP-2 produces a stronger pulse but with cortisol + prolactin signal — choose when maximum GH amplitude is the goal and the side-effect tolerance is acceptable.
- GHRP-2
- 100–200 mcg SQ · pre-sleep
- CJC-1295 (no DAC)
- 100 mcg SQ · same injection
- Primary benefit
- High-amplitude GH pulse, body composition
Thymosin α-1
— no documented stacks