Side-by-side · Research reference

GHRP-6vsThymalin

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

APhase 1Reviewed10/36 cited

BHuman-MechanisticDraft12/40 cited

GHRP-6

Hexapeptide GHRP · Strong appetite stimulant

100–200 mcgPer doseBowers 1990

Phase 1Evidence levelBowers 1990

~15 minHalf-lifeMalagón 1999

SQ · Multiple sites · 1–3×/day

Thymalin

Immune restorer · Russian peptide bioregulator

5–10 mgPer cycle doseKhavinson 2002

HumanMechanisticKhavinson 2002

HoursHalf-life (est)

IM · Daily for 5–10 days · 1-2×/year

01Mechanism of Action

Parameter

GHRP-6

Thymalin

Primary target

Ghrelin receptor (GHS-R1a)Bowers 1990

T-cell precursors + thymus-axis maturation pathwayKhavinson 2002

Pathway

GHS-R1a → Gαq → Ca²⁺ → GH release; central appetite driveBowers 2002

Modulation of T-cell differentiation + thymic hormone restoration in age-involuted thymusKhavinson 2002

Downstream effect

GH pulse + strong appetite stimulation; modest IGF-1 elevationBowers 2002

Restored T-cell populations, improved immune surveillance, reduced infection rates in elderlyKhavinson 2002

Feedback intact?

—

Origin

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

Polypeptide fraction isolated from calf thymus extractKhavinson 2002

Antibody development

—

02Dosage Protocols

Parameter

GHRP-6

Thymalin

Standard dose

100–200 mcg per injectionBowers 1990

5–10 mg / day IM × 5–10 daysKhavinson 2002

Frequency

1–3× per day

Once daily during cycle

Lower / starter dose

50 mcg per dose

2.5 mg / day

Evidence basis

Phase 1 + clinical practiceBowers 1990

Russian clinical + in vitroKhavinson 2002

Duration

8–12 weeks on / 4 off

5–10 day cycles, 1–2× per year

Reconstitution

Bacteriostatic water

Saline or bacteriostatic water

Timing

Pre-meal preferred for appetite support

Morning preferred

Half-life

~15 minMalagón 1999

Hours (estimated)

04Side Effects & Safety

Parameter

GHRP-6

Thymalin

Hunger

Pronounced — defining feature vs ipamorelin

—

Cortisol elevation

Mild

—

Prolactin elevation

Mild

—

Injection site reaction

Mild

Mild erythema at IM site

Cancer risk

Contraindicated in active malignancy

—

Pregnancy / OB

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

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

Thymalin

·Pregnancy / breastfeeding
·Bovine protein hypersensitivity

Relative Contraindications

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

Thymalin

·Active autoimmune disease
·Concurrent immunosuppressant therapy

05Administration Protocol

Parameter

GHRP-6

Thymalin

1. Reconstitution

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.

Add 1–2 mL saline or bacteriostatic water per 10 mg vial.

2. Injection site

SQ — abdomen. Rotate sites.

Intramuscular — deltoid or gluteal. Rotate sites.

3. Timing

Pre-meal for appetite support; pre-sleep for GH alignment.

Morning preferred during cycle.

4. Storage

Lyophilised: room temp. Reconstituted: refrigerate ≤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

GHRP-6

— no documented stacks

Thymalin

+ Thymosin α-1

Moderate

View Thymosin α-1 →

Thymalin 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

Khavinson 2002 Camerini 2001