Side-by-side · Research reference

MT-1vsThymalin

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

AFDA-ApprovedHUMAN-REVIEWED9/51 cited

BHuman-MechanisticAUTO-DRAFTED12/40 cited

MT-1

α-MSH Analogue · FDA-Approved

16 mgImplant dose

13 AAPeptide lengthChawathe 2026

2019FDA approval

SQ Implant · 60-Day Release

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

MT-1

Thymalin

Primary target

Melanocortin-1 receptor (MC1R) on melanocytesLangan 2010

T-cell precursors + thymus-axis maturation pathwayKhavinson 2002

Pathway

α-MSH analogue → MC1R activation → cAMP elevation → MITF transcription → eumelanin synthesis

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

Downstream effect

Increased melanogenesis, photoprotection, reduced UV sensitivityLangan 2010

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

Feedback intact?

Yes — exogenous MC1R agonism does not suppress endogenous α-MSH production

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Origin

Synthetic 13-AA peptidomimetic with norleucine (position 4) and D-phenylalanine (position 7) substitutions for metabolic stabilityChawathe 2026

Polypeptide fraction isolated from calf thymus extractKhavinson 2002

Antibody development

—

02Dosage Protocols

Parameter

MT-1

Thymalin

Standard dose

16 mg subcutaneous implant

FDA-approved formulation (Scenesse).

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

Frequency

Every 60 days

Sustained release implant — no daily administration required.

Once daily during cycle

Evidence basis

Phase 3 RCT / FDA-approved orphan drug

Russian clinical + in vitroKhavinson 2002

Indication

Erythropoietic protoporphyria (EPP)

Narrow FDA approval — not licensed for cosmetic tanning.

—

Duration

Seasonal use (spring–autumn typical)

Aligned with peak UV exposure months.

5–10 day cycles, 1–2× per year

Route

Subcutaneous implant — upper arm or abdomen

—

Stability

Norleucine/D-Phe substitutions enhance peptidase resistance

Modified structure vs endogenous α-MSH (Met⁴, L-Phe⁷).

—

Lower / starter dose

—

2.5 mg / day

Reconstitution

—

Saline or bacteriostatic water

Timing

—

Morning preferred

Half-life

—

Hours (estimated)

04Side Effects & Safety

Parameter

MT-1

Thymalin

Nausea

Common (>10%) — mild, transient

—

Implant site reaction

Erythema, bruising, tenderness at insertion site

—

Hyperpigmentation

Generalised tanning (therapeutic effect), darkening of freckles/neviLangan 2010 Habbema 2017

Expected melanogenic response — complicates pigmented lesion surveillance.

—

Melanocytic changes

Rapid pigmentation of existing nevi; new melanocytic lesions reported with unregulated useHabbema 2017

Requires dermatologic monitoring; theoretical melanoma concern with chronic stimulation.

—

Headache

Occasional (MC1R-independent melanocortin effects)

—

Photosensitivity (paradoxical)

Rare phototoxic reactions despite melanin increase

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Contamination risk (unregulated)

Impurity, infection, blood-borne virus transmission from illicit melanotan productsLangan 2010 Habbema 2017

Applies to internet/gym-sourced 'melanotan' — not FDA-approved Scenesse.

—

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

Pregnancy / OB

—

Avoid

Absolute Contraindications

MT-1

·Hypersensitivity to afamelanotide or excipients
·Hepatic impairment (no safety data)
·Renal impairment (no safety data)

Thymalin

·Pregnancy / breastfeeding
·Bovine protein hypersensitivity

Relative Contraindications

MT-1

·History of melanoma or atypical nevi (melanocortin receptor stimulation concern)Habbema 2017
·Pregnancy/lactation (insufficient data)
·Photosensitive dermatoses (other than EPP)

Thymalin

·Active autoimmune disease
·Concurrent immunosuppressant therapy

05Administration Protocol

Parameter

MT-1

Thymalin

1. Implant insertion

Performed by trained healthcare provider. Sterile technique. Small incision in upper arm (triceps) or lower abdomen using trocar. 16 mg rod (4 mm × 1.5 cm) inserted subcutaneously.

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

2. Site care

Pressure applied post-insertion. Sterile dressing × 24 hrs. Avoid strenuous activity for 24–48 hrs to prevent extrusion.

Intramuscular — deltoid or gluteal. Rotate sites.

3. Release kinetics

Slow biodegradable polymer matrix releases afamelanotide over 60 days, maintaining therapeutic plasma levels without daily dosing.

Morning preferred during cycle.

4. Repeat dosing

New implant every 60 days during high UV season (spring–autumn in temperate climates). Rotate implant sites to avoid scarring.

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

5. Monitoring

Baseline and periodic dermatologic exams to document pigmented lesions. Patient education on self-examination for new/changing nevi.

23–25G, 25–38 mm IM needle.

06Stack Synergy

MT-1

— 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