Side-by-side · Research reference

RetatrutidevsThymalin

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

APhase 2HUMAN-REVIEWED1/41 cited

BHuman-MechanisticAUTO-DRAFTED12/40 cited

Retatrutide

Triple-receptor agonist · Phase 3

1–12 mgWeekly dose

24.2%Body-weight ↓

~6 daysHalf-life (est)

SQ · Abdomen · Once weekly

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

Retatrutide

Thymalin

Primary target

GLP-1R + GIPR + Glucagon receptor (triple agonism)Jastreboff 2023

T-cell precursors + thymus-axis maturation pathwayKhavinson 2002

Pathway

Triple-receptor activation → ↑insulin (GLP-1+GIP), ↓gastric emptying, ↑lipid handling, ↑energy expenditure (glucagon component)

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

Downstream effect

Maximal weight loss across class. Glucagon component drives lipolysis and energy expenditure beyond GLP-1+GIP alone

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

Feedback intact?

—

Origin

Synthetic peptide engineered for balanced affinity at three incretin / glucagon receptors

Polypeptide fraction isolated from calf thymus extractKhavinson 2002

Antibody development

—

02Dosage Protocols

Parameter

Retatrutide

Thymalin

Standard dose

12 mg / week (max efficacy)

Phase 2 trial dose. Phase 3 dosing TBD.

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

Frequency

Once weekly

Once daily during cycle

Titration schedule

2 mg → 4 mg → 8 mg → 12 mg over 16 weeks

—

Evidence basis

Phase 2 trial; Phase 3 ongoing

Russian clinical + in vitroKhavinson 2002

Duration

Indefinite for chronic indication (presumed)

5–10 day cycles, 1–2× per year

Reconstitution

Investigational; not commercially available

Saline or bacteriostatic water

Timing

Any time of day

Morning preferred

Half-life

~6 days (estimated from class)

Hours (estimated)

Lower / starter dose

—

2.5 mg / day

04Side Effects & Safety

Parameter

Retatrutide

Thymalin

GI symptoms

Nausea, vomiting, diarrhea (very common, dose-dependent)

—

Heart rate

↑ resting HR (3–7 bpm at 12 mg)

—

Glucose handling

Glycemic improvement; rare hyperglycemia from glucagon component

—

Pancreatitis risk

Class warning

—

Thyroid C-cell tumours

Class warning (presumed)

—

Pregnancy / OB

Avoid (insufficient data)

Avoid

Injection site reaction

—

Mild erythema at IM site

Allergic reaction

—

Rare hypersensitivity to bovine-derived polypeptide

Autoimmune flare

—

Theoretical risk in active autoimmune disease

Long-term safety

—

Limited Western data

Absolute Contraindications

Retatrutide

·MTC personal or family history (presumed class effect)
·Pregnancy / breastfeeding

Thymalin

·Pregnancy / breastfeeding
·Bovine protein hypersensitivity

Relative Contraindications

Retatrutide

·Severe gastroparesis
·History of pancreatitis
·Severe cardiovascular disease (HR signal)

Thymalin

·Active autoimmune disease
·Concurrent immunosuppressant therapy

05Administration Protocol

Parameter

Retatrutide

Thymalin

1. Reconstitution

Investigational peptide. Research vials reconstituted with bacteriostatic water per label.

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

2. Injection site

SQ — abdomen, thigh, or upper arm. Rotate weekly.

Intramuscular — deltoid or gluteal. Rotate sites.

3. Timing

Once weekly, same day.

Morning preferred during cycle.

4. Storage

Refrigerate 2–8 °C. Light-protected.

Lyophilised: refrigerate, light-protected. Reconstituted: use immediately.

5. Needle

27–31G, 4–8 mm insulin syringe.

23–25G, 25–38 mm IM needle.

06Stack Synergy

Retatrutide

— 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