Side-by-side · Research reference

SemaxvsThymalin

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

AHuman-MechanisticDraft12/39 cited

BHuman-MechanisticDraft12/40 cited

Semax

Cognitive enhancer · Russian Pharma

200–600 mcg/doseIntranasalKaplan 2017

HumanMechanisticKaplan 2017

~30 minOnset

Intranasal · 2–3×/day during cognitive demand

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

Semax

Thymalin

Primary target

BDNF / NGF expression + monoamine modulationKaplan 2017

T-cell precursors + thymus-axis maturation pathwayKhavinson 2002

Pathway

↑ BDNF + NGF synthesis + 5-HT modulation → neuroplasticity + anxiolysis + cognitive enhancementKaplan 2017

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

Downstream effect

Improved memory + attention; reduced anxiety; neuroprotection in ischemiaKaplan 2017

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

Feedback intact?

—

Origin

Synthetic 7-AA peptide derived from ACTH(4-7) with C-terminal Pro-Gly-Pro stabilising tailKaplan 2017

Polypeptide fraction isolated from calf thymus extractKhavinson 2002

Antibody development

—

02Dosage Protocols

Parameter

Semax

Thymalin

Standard dose

200–600 mcg / dose intranasalKaplan 2017

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

Frequency

2–3× per day during cognitive demand

Once daily during cycle

Lower / starter dose

100 mcg / dose

2.5 mg / day

Evidence basis

Human-mechanistic + Russian clinicalKaplan 2017

Russian clinical + in vitroKhavinson 2002

Duration

10–14 day cycles, repeated PRN

5–10 day cycles, 1–2× per year

Reconstitution

Pre-formulated nasal spray (commercial); research vial: bacteriostatic water

Saline or bacteriostatic water

Timing

Morning + early afternoon

Morning preferred

Half-life

Short plasma; CNS effect lasts ~3–6 hr

Hours (estimated)

04Side Effects & Safety

Parameter

Semax

Thymalin

Nasal irritation

Mild burning or congestion (transient)

—

Sleep disruption

Late-day dosing may interfere with sleep

—

Headache

Uncommon, transient

—

Long-term safety

Limited Western RCT data

Limited Western data

Pregnancy / OB

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

Absolute Contraindications

Semax

·Pregnancy / breastfeeding

Thymalin

·Pregnancy / breastfeeding
·Bovine protein hypersensitivity

Relative Contraindications

Semax

·Active psychiatric instability
·Concurrent strong stimulants

Thymalin

·Active autoimmune disease
·Concurrent immunosuppressant therapy

05Administration Protocol

Parameter

Semax

Thymalin

1. Form

Pre-formulated nasal spray (commercial) or research vial reconstituted with bacteriostatic water.

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

2. Administration

Intranasal — 2–3 sprays per nostril per dose. Tilt head slightly back.

Intramuscular — deltoid or gluteal. Rotate sites.

3. Timing

Morning + early afternoon. Avoid evening (sleep disruption).

Morning preferred during cycle.

4. Storage

Refrigerate after reconstitution; light-protected.

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

5. Caveat

Cycle on/off to avoid neurochemical adaptation.

23–25G, 25–38 mm IM needle.

06Stack Synergy

Semax

+ Selank

Moderate

View Selank →

Semax (cognitive enhancer, BDNF/NGF) and Selank (anxiolytic + immune) form the canonical Russian "neuro stack" — both intranasal peptide bioregulators with complementary axes. Semax for cognitive demand; Selank for stress mitigation.

Semax: 200–600 mcg intranasal · morning + afternoon
Selank: 150–300 mcg intranasal · midday + early evening
Primary benefit: Cognitive enhancement + stress mitigation

Kaplan 2017 Zaderej 2014

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