Side-by-side · Research reference
IpamorelinvsThymalin
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 1Reviewed21/57 cited
BHuman-MechanisticDraft12/40 cited
Ipamorelin
Selective GHRP · Ghrelin Mimetic
SQ · Multiple sites · 1–3×/day
Thymalin
Immune restorer · Russian peptide bioregulator
IM · Daily for 5–10 days · 1-2×/year
01Mechanism of Action
Parameter
Ipamorelin
Thymalin
Primary target
Ghrelin receptor (GHS-R1a) on anterior pituitaryRaun 1998
T-cell precursors + thymus-axis maturation pathwayKhavinson 2002
Pathway
GHS-R1a binding → Gαq/11 → ↑intracellular Ca²⁺ → GH vesicle exocytosisRaun 1998Bowers 1991
Modulation of T-cell differentiation + thymic hormone restoration in age-involuted thymusKhavinson 2002
Downstream effect
GH pulse amplification, IGF-1 elevation, recovery and lipolytic effectsBowers 2002
Restored T-cell populations, improved immune surveillance, reduced infection rates in elderlyKhavinson 2002
Origin
Pentapeptide H-Aib-His-D-2-Nal-D-Phe-Lys-NH₂; rationally designed for ghrelin-receptor selectivityRaun 1998
Polypeptide fraction isolated from calf thymus extractKhavinson 2002
Antibody development
Not reported in short-term studies
—
02Dosage Protocols
Parameter
Ipamorelin
Thymalin
Standard dose
200–300 mcg per injectionRaun 1998
Anecdotal community range; clinical doses 1–3 mg IV in trials.
5–10 mg / day IM × 5–10 daysKhavinson 2002
Frequency
1–3× per day
Once daily pre-sleep is most common; twice or thrice for advanced users.
Once daily during cycle
Lower / starter dose
100 mcg per dose
2.5 mg / day
Evidence basis
Phase 1 + clinical practiceRaun 1998Sigalos 2018
Russian clinical + in vitroKhavinson 2002
Duration
8–12 weeks on / 4 weeks off (anecdotal)
GHS-R desensitisation reported with continuous dosing.
5–10 day cycles, 1–2× per year
Reconstitution
Bacteriostatic water; typical 2 mL per 5 mg vial
Saline or bacteriostatic water
Timing
Pre-sleep + fasted preferred; 30 min away from food
Morning preferred
Half-life
~2 hoursRaun 1998
Longer than GHRP-6 (15 min); shorter than CJC-1295-DAC (~8 days).
Hours (estimated)
04Side Effects & Safety
Parameter
Ipamorelin
Thymalin
Hunger
Mild appetite increase via ghrelin-receptor crosstalk
—
Injection site reaction
Mild irritation possible
Mild erythema at IM site
GH excess (overdose)
Joint pain, edema, insulin resistance
—
IGF-1 elevation
Dose-dependent; monitor with chronic high-dose use
—
Cancer risk
Theoretical via GH/IGF-1 axis; contraindicated in active malignancy
—
Pregnancy / OB
Avoid
Avoid
Allergic reaction
—
Rare hypersensitivity to bovine-derived polypeptide
Autoimmune flare
—
Theoretical risk in active autoimmune disease
Long-term safety
—
Limited Western data
Absolute Contraindications
Ipamorelin
- ·Active malignancy or cancer history
- ·Pregnancy / breastfeeding
- ·Disrupted hypothalamic-pituitary axis
Thymalin
- ·Pregnancy / breastfeeding
- ·Bovine protein hypersensitivity
Relative Contraindications
Ipamorelin
- ·Untreated diabetes
- ·Severe insulin resistance
- ·Concurrent corticosteroid use (theoretical desensitisation)
Thymalin
- ·Active autoimmune disease
- ·Concurrent immunosuppressant therapy
05Administration Protocol
Parameter
Ipamorelin
Thymalin
1. Reconstitution
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL. Roll gently. Solution should be clear.
Add 1–2 mL saline or bacteriostatic water per 10 mg vial.
2. Injection site
Subcutaneous, abdomen or thigh. Rotate sites. Pinch fat for shallow SQ delivery.
Intramuscular — deltoid or gluteal. Rotate sites.
3. Timing
Pre-sleep optimal — aligns with natural GH pulse. Some protocols add a morning fasted dose.
Morning preferred during cycle.
4. Storage
Lyophilised: room temp, protected from light. Reconstituted: refrigerate 2–8 °C, use within 30 days.
Lyophilised: refrigerate, light-protected. Reconstituted: use immediately.
5. Needle
29–31G, 4–8 mm insulin syringe.
23–25G, 25–38 mm IM needle.
06Stack Synergy
Ipamorelin
+ Tesamorelin
StrongIpamorelin (GHRP) + tesamorelin (GHRH analogue) is the textbook dual-axis GH stack. They activate two distinct pituitary receptors — the ghrelin receptor and the GHRH receptor — producing a synergistic GH pulse larger than either alone. Ipamorelin's selectivity (no cortisol/prolactin spike) makes it the ideal GHRP partner for long-term protocols.
- Ipamorelin
- 200–300 mcg SQ · pre-sleep
- Tesamorelin
- 2 mg SQ · same injection · pre-sleep
- Primary benefit
- Maximal GH pulsatility, fat loss, recovery, sleep depth
+ CJC-1295 (no DAC)
StrongCJC-1295 (no DAC) is a short-acting GHRH analogue. Combined with ipamorelin (GHRP), the pulse is amplified across both receptor systems with timing similar to native physiology. Without the DAC modification, the stack maintains sharp peaks rather than the sustained elevation seen with CJC-1295-DAC + ipamorelin.
- Ipamorelin
- 200–300 mcg SQ · pre-sleep
- CJC-1295 (no DAC)
- 100 mcg SQ · same injection
- Primary benefit
- Pulsatile GH stimulation matching physiological pattern
Thymalin
+ Thymosin α-1
ModerateThymalin is a polypeptide complex; Thymosin α-1 is a single purified peptide. Both target the thymus-axis but at different levels — Thymalin restores broad thymic signaling; Tα-1 provides a specific molecular activator. Anecdotally combined for elderly immune support.
- Thymalin
- 5–10 mg IM · daily × 7 days
- Thymosin α-1
- 1.6 mg SQ · 2× weekly during the cycle
- Primary benefit
- Broad thymic restoration + targeted immune activation