GDF-11 (Growth Differentiation Factor 11) vs Thymalin
A neutral, side-by-side comparison of two anti-aging & longevity peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
GDF-11 (Growth Differentiation Factor 11)
TGF-β superfamily member proposed as a 'young blood factor' — circulating GDF-11 declines with age, and young plasma transfusion in parabiosis experiments reversed aging phenotypes in mice. A high-profile but contested research area: some studies show rejuvenating effects in heart, muscle, and brain; others using purified recombinant GDF-11 show cardiac hypertrophy and muscle wasting at pharmacologic doses.
Full profileThymalin
Thymus-derived peptide bioregulator developed in Russia containing a mixture of low-molecular-weight peptides extracted from calf thymus. Primarily studied for reversing immunological aging (immunosenescence) and extending healthy lifespan. Vladimir Khavinson's longitudinal research on elderly patients links thymalin administration to significant improvements in immune markers and all-cause mortality reduction.
Full profile| GDF-11 (Growth Differentiation Factor 11) | Thymalin | |
|---|---|---|
| Category | Anti-Aging & Longevity | Anti-Aging & Longevity |
| Also known as | GDF11, Bone Morphogenetic Protein 11, BMP-11, young blood factor | thymic peptide bioregulator, T-activin extract, thymus peptide, thymic bioregulator |
| Evidence | Research-stage | Research-stage |
| Dosing range | 0.1mg/kg–1mg/kg mg/kg, every 3–7 days (SC); research protocols vary widely | 5mg–20mg mg, 5–10 day course, 1–2x per year |
| Administration | Subcutaneous injection, Intravenous (research) | Intramuscular injection, Subcutaneous injection |
| Key side effects | Cardiac hypertrophy (at pharmacologic doses — the key safety concern), Muscle wasting and weight loss, Reproductive effects (GDF-11 inhibits spermatogenesis and folliculogenesis), Cachexia-like syndrome at high doses | Injection site reactions, Mild fever (rare), Temporary increase in immune activity (desired response), Rare hypersensitivity |
| Cited sources | 2 references | 2 references |
Key differences
- Administration: GDF-11 (Growth Differentiation Factor 11) — Subcutaneous injection, Intravenous (research); Thymalin — Intramuscular injection, Subcutaneous injection.
- Dosing units differ: GDF-11 (Growth Differentiation Factor 11) is dosed in mg/kg, Thymalin in mg — they operate at different scales.
- Frequency: GDF-11 (Growth Differentiation Factor 11) is typically every 3–7 days (SC); research protocols vary widely; Thymalin is 5–10 day course, 1–2x per year.
How each works
GDF-11 (Growth Differentiation Factor 11)
The 2013–2014 parabiosis studies from Amy Wagers' lab at Harvard proposed GDF-11 as the primary rejuvenating factor in young blood. However, subsequent work by Lee and others showed that purified recombinant GDF-11 at pharmacologic doses caused cardiac hypertrophy, muscle atrophy, and weight loss — opposite of the proposed rejuvenating effects. The field now views GDF-11 as highly dose-sensitive with a narrow therapeutic window, if one exists at all.
Thymalin
Thymalin contains multiple bioactive peptides that stimulate T-lymphocyte differentiation and restore thymic function that declines with age. In Khavinson's 6-year controlled trial of elderly patients (78–89 years), annual thymalin courses were associated with significantly lower mortality and improved immune parameters vs. controls. Proposed mechanisms include telomerase activation in immune cells and restoration of thymic epithelial cell function.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.