Quick Comparison

CrystagenHGH 191AA
Half-LifeApproximately 30 minutes (acute pharmacology); proposed gene-expression effects outlast plasma exposure2-3 hours
Typical DosageOral (capsule): 100-200 mg once daily for 10-30 day cycles, repeated 2-3 times per year. Subcutaneous injection: 1-5 mg per dose, alternate days for 10-20 day cycles. Standard Khavinson cycling protocol.Clinical (GH deficiency): 0.2-0.6 mg subcutaneous once daily. Anti-aging: 1-2 IU subcutaneous once daily, typically before bed. Bodybuilding: 2-4 IU subcutaneous once daily (up to 6-8 IU in advanced protocols). All doses injected subcutaneously, preferably in the evening to coincide with natural GH pulse timing.
AdministrationOral capsule or subcutaneous injection (cycled)Subcutaneous or intramuscular injection (daily)
Research Papers1 papers0 papers
Categories

Mechanism of Action

Crystagen

Crystagen is a short Khavinson tripeptide (Glu-Asp-Pro) positioned as the immune and thymus-targeted bioregulator within the wider Khavinson peptide family. The proposed mechanism follows the standard family framework: short peptides interact with gene promoter sequences in thymic and lymphocyte cell nuclei, modulating expression of genes involved in T cell maturation, cytokine production, and broader immune regulation.

Proposed effects include support for thymic function — particularly relevant given the well-documented age-related thymic involution that contributes to immunosenescence in older adults — alongside modulation of lymphocyte chromatin organisation and immune cell maturation pathways. Russian research has reported crystagen-induced improvements in lymphocyte counts, T helper cell function, and clinical recovery from infections in elderly populations and in patients recovering from immunosuppressive treatments. The peptide is often used alongside thymalin (a related thymic peptide preparation also in this database) as part of broader Khavinson immune-support protocols.

As with the rest of the Khavinson family, the efficacy evidence base sits within Russian gerontology and immunology research with limited independent Western validation. Crystagen is not validated as a treatment for primary immunodeficiency, HIV-related immune dysfunction, or other formally diagnosed immune conditions, and should not displace evidence-based immune therapy. The brief plasma half-life (around 30 minutes) reflects the proposed model of transient signalling triggering longer-lasting transcriptional changes in immune cell populations.

HGH 191AA

Human Growth Hormone is a 191-amino-acid single-chain polypeptide secreted by somatotroph cells of the anterior pituitary gland. It exerts its effects through two distinct pathways: direct action via GH receptors and indirect action through insulin-like growth factor 1 (IGF-1). When HGH binds to the GH receptor (a type I cytokine receptor), it induces receptor dimerization and activates the JAK2/STAT5 signaling cascade, which directly stimulates gene transcription for protein synthesis, cell proliferation, and lipolysis.

The indirect pathway is equally important. GH receptor activation in hepatocytes stimulates the production and secretion of IGF-1, a 70-amino-acid peptide that circulates bound to IGF binding proteins (primarily IGFBP-3 and the acid-labile subunit). Circulating IGF-1 acts on virtually every tissue in the body — promoting amino acid uptake and protein synthesis in skeletal muscle, stimulating chondrocyte proliferation in growth plates, enhancing osteoblast activity for bone formation, and supporting neuronal survival and myelination.

GH also has profound effects on metabolism independent of IGF-1. It directly stimulates lipolysis in adipocytes by activating hormone-sensitive lipase, mobilizing stored fat as free fatty acids for energy. It antagonizes insulin action in peripheral tissues (hence the diabetogenic risk), shifting the body's fuel preference from glucose to fatty acids. In muscle, GH promotes nitrogen retention and positive protein balance. The pulsatile pattern of natural GH secretion — with the largest pulse during deep sleep — is important for its physiological effects, which is why exogenous GH protocols often try to mimic this pattern.

Risks & Safety

Crystagen

Common

generally reported as well tolerated.

Serious

very limited Western clinical data; theoretical concern with use in autoimmune disease (immune-modulating peptides may unpredictably affect autoimmune activity).

Rare

allergic reactions. Should not replace evidence-based immune therapy in serious immunodeficiency.

HGH 191AA

Common

joint pain, wrist pain/numbness (carpal tunnel), water retention and swelling, headache, tingling in hands/feet.

Serious

can make your body less responsive to insulin (raising blood sugar), may accelerate growth of existing tumours, enlarged jaw/hands/feet with long-term overuse.

Rare

increased pressure in the skull, breast tissue growth in men, underactive thyroid. Not suitable for people with active cancer or severe illness.

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