Side-by-side · Research reference
TesamorelinvsThymalin
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AFDA-ApprovedVerified27/68 cited
BHuman-MechanisticDraft12/40 cited
Tesamorelin
GHRH Analogue · FDA-Approved
SQ · Abdomen · Once Daily
Thymalin
Immune restorer · Russian peptide bioregulator
IM · Daily for 5–10 days · 1-2×/year
01Mechanism of Action
Parameter
Tesamorelin
Thymalin
Primary target
Hypothalamic GHRH receptorsEGRIFTA® (tesamorelin for inje 2010
T-cell precursors + thymus-axis maturation pathwayKhavinson 2002
Pathway
GHRH → Pituitary GH release → Liver IGF-1 synthesisFalutz 2007
Modulation of T-cell differentiation + thymic hormone restoration in age-involuted thymusKhavinson 2002
Downstream effect
Increased GH pulsatility, elevated IGF-1, lipolysis of visceral adipose tissueFalutz 2010
Restored T-cell populations, improved immune surveillance, reduced infection rates in elderlyKhavinson 2002
Feedback intact?
Yes — physiological pulsatility preserved
—
Origin
Synthetic 44-AA GHRH analogue with trans-3-hexenoic-acid modification for stabilityEGRIFTA® (tesamorelin for inje 2010
Polypeptide fraction isolated from calf thymus extractKhavinson 2002
02Dosage Protocols
Parameter
Tesamorelin
Thymalin
Standard dose
2 mg / dayEGRIFTA® (tesamorelin for inje 2010
FDA-approved protocol.
5–10 mg / day IM × 5–10 daysKhavinson 2002
Frequency
Once daily (morning or pre-sleep)
Aligns with natural GH pulse.
Once daily during cycle
Lower / starter dose
1 mg / dayFalutz 2010
1 mg still produces significant IGF-1 elevation.
2.5 mg / day
Duration
12–52 weeks
VAT returns within months of stopping.
5–10 day cycles, 1–2× per year
Reconstitution
Sterile water per labeling
Preserved at 2–8 °C after reconstitution.
Saline or bacteriostatic water
Timing
Empty stomach, pre-sleep preferred
Morning preferred
Half-life
~26 min (plasma)EGRIFTA® (tesamorelin for inje 2010
Modified vs native GHRH (7 min t½).
Hours (estimated)
03Metabolic / Fat Loss Evidence
Parameter
Tesamorelin
Thymalin
Primary fat target
Visceral adipose tissue (VAT) — abdominal
—
Effect on lean mass
Modest lean mass preservation / slight increase
—
Effect reversibility
VAT returns within months of stopping
—
Key publication
Falutz et al. NEJM 2007 · Falutz JCEM 2010 · FDA approval 2010Falutz 2007Falutz 2010EGRIFTA® (tesamorelin for inje 2010
—
04Side Effects & Safety
Parameter
Tesamorelin
Thymalin
Injection site reaction
Erythema, pruritus, redness (common)
Mild erythema at IM site
Fluid retention / Edema
Peripheral edema, arthralgia, carpal tunnel (GH-axis effect)
—
IGF-1 elevation
Dose-dependent; supraphysiological levels = discontinue
—
Cancer risk
Contraindicated in active malignancy (GH/IGF-1 axis); theoretical tumour growth riskEGRIFTA® (tesamorelin for inje 2010
—
Antibody formation
~50% at 26 weeks; non-neutralising in most; rare hypersensitivity (<1%)Sévigny 2018
—
GI symptoms
Nausea, diarrhea (mild, transient)
—
Allergic reaction
—
Rare hypersensitivity to bovine-derived polypeptide
Autoimmune flare
—
Theoretical risk in active autoimmune disease
Long-term safety
—
Limited Western data
Absolute Contraindications
Tesamorelin
- ·Active malignancy or history of treated cancer
- ·Pregnancy
- ·Hypersensitivity to tesamorelin or mannitol
- ·Disruption of hypothalamic-pituitary axis (trauma, tumour, radiation)
Thymalin
- ·Pregnancy / breastfeeding
- ·Bovine protein hypersensitivity
Relative Contraindications
Tesamorelin
- ·Untreated diabetes (monitor HbA1c)
- ·Severe carpal tunnel syndrome
- ·Acute critical illness
Thymalin
- ·Active autoimmune disease
- ·Concurrent immunosuppressant therapy
05Administration Protocol
Parameter
Tesamorelin
Thymalin
1. Reconstitution
Add 2.1 mL sterile water to 2 mg lyophilised vial. Roll gently — do not shake. Solution should be clear.
Add 1–2 mL saline or bacteriostatic water per 10 mg vial.
2. Injection site
Subcutaneous — abdomen preferred. Rotate sites (avoid same spot within 2 cm). Avoid navel and waistband area.
Intramuscular — deltoid or gluteal. Rotate sites.
3. Timing
Once daily. Preferred: evening, 2–3 hrs post-meal, before sleep — aligns with natural GH secretion pulse.
Morning preferred during cycle.
4. Storage
Lyophilised: room temp, light-protected. Reconstituted: refrigerate 2–8 °C, use within 21 days.
Lyophilised: refrigerate, light-protected. Reconstituted: use immediately.
5. Needle
27–31G, 4–8 mm insulin syringe. Pinch skin, 45° angle for lean individuals.
23–25G, 25–38 mm IM needle.
06Stack Synergy
Tesamorelin
+ Ipamorelin
StrongTesamorelin (GHRH analogue) and ipamorelin (GHRP / ghrelin mimetic) act on two distinct receptor systems to amplify GH release synergistically — GHRH receptor + ghrelin receptor. This dual-axis stimulation produces a more robust, sustained GH pulse than either alone while maintaining physiological pulsatility. Ipamorelin is highly selective with minimal cortisol or prolactin elevation, making it the preferred GHRP pairing.
- Tesamorelin
- 2 mg SQ · evening
- Ipamorelin
- 200–300 mcg SQ · same injection
- Frequency
- Once daily, pre-sleep
- Primary benefit
- Maximal GH pulsatility, fat loss, recovery, sleep quality
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