Thymogen
Timogen · α-glutamyl-tryptophan · H-Glu-Trp-OH · Oglufanide · IM-862
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At a glance
Overview
Thymogen: The Quiet Immune Reset#
Thymogen is the α-glutamyl-tryptophan dipeptide — a two-amino-acid fragment of thymopoietin-II that punches well above its molecular weight. In the bodybuilding and looksmaxxing community it has earned a niche as the quiet immune reset: a short 10-day pulse that normalizes CD4/CD8 ratios, tunes cytokine output, and restores thymic signaling in users who've beaten themselves up with prep dieting, long AAS blasts, or a hard URTI. Outside Russia, the same molecule was developed as Oglufanide / IM-862 and carried through Phase II trials for Kaposi sarcoma and hepatitis C, which is where most of the antiangiogenic and antiviral pharmacology data comes from.
Unlike BPC-157 or TB-500, Thymogen is not a "feel-it-in-a-week" compound. It belongs to the Khavinson-school bioregulator family alongside Thymalin and Epitalon, where the value shows up on bloodwork and in how quickly the subject shakes off the next respiratory infection rather than in an acute subjective kick. Physique-focused users reach for it during post-competition immune crashes, as a quarterly on-cycle thymic pulse during long blasts, perioperatively around gyno excision or hair transplants, and as the "immune leg" of a twice-yearly bioregulator stack.
"Thymogen is an isolated fragment of thymopoietin-II and acts as a regulator of lymphoid system cell differentiation, exhibiting effects even at nanomolar concentrations." — Khavinson et al., Int J Mol Sci (2023)
The sections below cover documented Thymogen dosage ranges (100 mcg label-equivalent up to the 2.5 mg Oglufanide schedule), subQ vs. intranasal administration, the standard 7–14 day block cadence, common stacking patterns with Thymalin, Epitalon, and BPC-157, and the reconstitution and sourcing pitfalls that trip up first-time users.
How Thymogen works
Thymogen is the synthetic dipeptide α-L-glutamyl-L-tryptophan — an isolated two-residue fragment of the native thymic hormone thymopoietin-II. Despite its minimal structure, it reproduces the core lymphoid-regulatory signalling of the parent molecule and is active at nanomolar tissue concentrations. Its value for physique- and health-focused users is not a felt "kick" but a measurable re-tuning of immune and redox state that makes prep blocks, long AAS cycles, and perioperative windows considerably less fragile.
Thymopoietin Mimicry and T-Cell Maturation#
The central mechanism is differentiation signalling on lymphoid precursors. α-Glu-Trp drives immature CD3⁺ thymocytes toward mature CD4⁺ and CD8⁺ lineages and restores a normalized CD4/CD8 ratio in immunosuppressed models — the exact defect seen in post-prep bodybuilders, subjects finishing long blasts, and anyone recovering from a viral hit.
"Peptide SCV-07 (alpha-glutamyl-tryptophan) was shown to stimulate differentiation of CD3+ thymocytes and normalize the CD4/CD8 ratio in immunosuppressed mice." — Simbirtsev A, Kolobov A, Zabolotnych N, et al., International Journal of Immunopharmacology, 1997
"Thymogen is an isolated fragment of thymopoietin-II and acts as a regulator of lymphoid system cell differentiation, exhibiting effects even at nanomolar concentrations." — Khavinson VK, Popovich IG, Linkova NS, et al., International Journal of Molecular Sciences, 2023
This is why immunological effects persist for days to weeks after a 10-day block despite a plasma half-life measured in minutes — the compound reshapes the lymphocyte pool rather than occupying a receptor at steady state.
Cytokine Tuning Rather Than Broad Stimulation#
Thymogen is not an immune "booster" in the crude sense. It dampens TNFα-driven IL-1α output while upregulating ICAM-1 on endothelium, which is the signature of an immunoregulator — something that pulls an out-of-range system back toward baseline rather than pushing it in one direction.
"The study demonstrates that α-glutamyl–tryptophan reduces TNFα-induced IL-1α secretion while upregulating cell adhesion molecule ICAM-1, consistent with its role as an immunoregulatory modulator." — Kozlov VA, Tikhonova EP, Savchenko AA, et al., Pharmaceuticals, 2023
Practically, this is the mechanism behind the reduced URTI frequency users report during high-volume prep and behind the quieter CRP curves seen when a 10-day block is run alongside a heavy AAS blast. It also explains why Thymogen does not provoke the flu-like malaise that higher-intensity immunostimulants (IFN, some TLR agonists) produce.
Antioxidant and Hepatoprotective Signalling#
A second, under-appreciated arm of the mechanism is redox. In hydrazine-induced toxic hepatitis models, α-Glu-Trp measurably raises catalase activity and lowers lipid peroxidation markers — an outcome relevant to anyone running oral 17α-alkylated compounds or extended high-dose injectable cycles.
"Administration of the compound increased catalase activity in both plasma and liver homogenate, and reduced the levels of lipid peroxidation products, demonstrating antioxidant and hepatoprotective effects." — Chulanova AA, Smakhtina AM, Mal GS, et al., Research Results in Pharmacology, 2024
The hepatoprotection is not on the scale of TUDCA or NAC and should not replace them in a liver-support stack — but it stacks cleanly on top and targets a different arm (lymphoid-mediated inflammation contributing to hepatic oxidative load).
Antiangiogenic Activity (Oglufanide / IM-862 Arm)#
The same molecule was developed in the US as Oglufanide / IM-862 specifically for its VEGF-inhibitory, antiangiogenic behaviour, entering Phase II programs in Kaposi sarcoma and chronic hepatitis C at intranasal doses roughly 25× higher than the Russian immune-support label.
"Oglufanide (IM-862) was investigated for antiangiogenic activity and as an adjunct in chronic hepatitis C, utilizing intranasal administration at daily doses of 2.5 mg in human trials." — DrugBank, DrugBank Online, 2024
For physique-focused users this arm is mostly informational — antiangiogenic signalling is the opposite of what BPC-157 does and is not a goal of a bodybuilding protocol. The takeaway is that dose matters: the 100 µg bioregulator dose sits far below the antiangiogenic range used in oncology trials, and users stacking Thymogen with BPC-157 for perioperative or tendon-healing applications should keep the dose in the Cytomed-label window (100–200 µg) rather than drifting up into the IM-862 range.
Route, Proteolysis, and Why Oral Fails#
Mechanism also dictates route. As an unmodified dipeptide, α-Glu-Trp is cleaved rapidly by brush-border and plasma peptidases — plasma t½ is in the single-digit-minutes range, and this is the problem Russian research groups are now trying to solve with D-alanine-substituted analogues for oral use. Until those analogues are commercially available, the viable routes remain subcutaneous, intramuscular, and intranasal (the registered Cytomed spray form and the IM-862 HCV trials both used intranasal specifically to bypass GI proteolysis). Oral dosing of the dipeptide itself is effectively a disposal of compound — a recurring pitfall when users extrapolate from oral bioregulator marketing to Thymogen.
The practical synthesis across these mechanisms: Thymogen is a lymphoid differentiation signal with bolt-on redox and endothelial-tuning effects, delivered as a short 10-day pulse that produces weeks of downstream effect. It sits cleanly alongside BPC-157/TB-500 (healing arm), Thymalin (broader thymic signalling), and Epitalon (pineal/telomerase arm) without mechanistic overlap, which is why it has become a staple of the quarterly bioregulator cadence rather than a daily-for-life compound.
Protocol
| Level | Dose | Frequency | Notes |
|---|---|---|---|
| Low | 100–100 mcg | Once daily | Documented entry-level range |
| Mid | 100–200 mcg | Once daily | Most commonly studied range |
| High | 500–1000 mcg | Once daily | Administered in discrete 7–14 day blocks rather than continuously. Quarterly or twice-yearly cadence is standard; intranasal dosing splits across 2–4 administrations per day. |
Cycle length & outcomes
Documented cycle
1–2 weeks
Plateau after
2 wks
Cycle Notes#
Thymogen does not cycle like a hormonal compound or even like a conventional healing peptide. It is administered in discrete short blocks — typically 7–14 days — separated by weeks or months of washout, rather than run continuously. The underlying logic is mechanistic: the dipeptide drives lymphocyte differentiation and then the lymphoid system carries the effect forward for weeks. Continuous daily administration is not how the Cytomed registration data, the Oglufanide clinical program, or the Khavinson-school bioregulator protocols were designed, and the community has not found benefit in stretching blocks past two weeks.
Thymogen Protocol by Goal#
| Goal | Block Length | Daily Dose | Cadence |
|---|---|---|---|
| Acute URTI / post-illness rebound | 7 days | 100mcg subQ or 25mcg/nostril 3–4×/day | As needed |
| Post-competition / end-of-prep immune recovery | 10 days | 100mcg subQ | Per prep cycle |
| Perioperative (gyno excision, lipo, HT, injury repair) | 10–14 days | 100–200mcg subQ | 3 days pre → 7–10 days post |
| On-cycle immune support during long AAS blasts | 10 days | 100–200mcg subQ | Every 8–12 weeks |
| Longevity / bioregulator stack (Khavinson cadence) | 10 days | 100mcg subQ | 2× per year (spring/autumn) |
| Antiviral / antiangiogenic (Oglufanide-style) | 10–14 days | 500–1000mcg subQ | 1–2× per year, off-label |
Loading and Tapering#
Neither is required and neither is used. The registered Cytomed protocol is a flat 100mcg daily dose from day 1 to day 10, and community practice follows the same pattern. There is no endogenous axis to ramp up or ramp down — the compound is not hormonal, not suppressive, and does not downregulate any receptor system at the doses in use. Blocks start at target dose on day 1 and stop on the final day.
"Thymogen is an isolated fragment of thymopoietin-II and acts as a regulator of lymphoid system cell differentiation, exhibiting effects even at nanomolar concentrations." — Khavinson et al., International Journal of Molecular Sciences (2023)
This is why the short plasma half-life (minutes) is not the relevant endpoint. The cycle length is governed by how long it takes lymphocyte populations to re-mature and rebalance, not by drug exposure kinetics.
Onset Timing#
- Acute infection context: subjective improvement in symptom severity and duration is typically reported within 3–5 days of initiating a block, consistent with the Cytomed label's 7–10 day acute-infection window.
- Immune recovery / post-prep context: measurable shifts in lymphocyte counts and hsCRP are the expected marker, detectable on bloodwork drawn at the end of a 10-day block versus a pre-block baseline.
- Bioregulator / longevity context: the effect is quiet by design. Users expecting a Thymosin-α1-style "immune kick" are routinely disappointed. The payoff here is structural — lymphoid maturation and CD4/CD8 normalization — rather than a felt stimulant-like response.
"Peptide SCV-07 (alpha-glutamyl-tryptophan) was shown to stimulate differentiation of CD3+ thymocytes and normalize the CD4/CD8 ratio in immunosuppressed mice." — Simbirtsev et al., International Journal of Immunopharmacology (1997)
Bloodwork Cadence#
Thymogen is not a bloodwork-driven compound in the way AAS or GH are — there is no lipid, hematocrit, or endocrine panel to monitor. Where users want to verify response, the relevant labs are:
- CBC with differential (lymphocyte subsets if accessible) pre-block and 3–5 days post-block
- hsCRP pre-block and post-block, particularly if baseline is elevated from a hard training cycle or AAS blast
- LFTs are optional and mainly relevant if stacking with hepatotoxic 17-aa orals — Thymogen itself shows a hepatoprotective signal in the hydrazine model rather than any hepatic stress
"Administration of the compound increased catalase activity in both plasma and liver homogenate, and reduced the levels of lipid peroxidation products, demonstrating antioxidant and hepatoprotective effects." — Chulanova et al., Research Results in Pharmacology (2024)
Thymogen Stack Timing Within a Block#
When stacked with other bioregulators, the community runs them on overlapping 10-day windows rather than staggered:
- Thymogen 100mcg + Thymalin 10mg daily, both subQ, days 1–10 — the dominant pairing.
- Thymogen + Epitalon 5–10mg daily, days 1–10 (or Epitalon extended to day 20) — the Khavinson longevity block.
- Thymogen + BPC-157 250–500mcg + TB-500 2mg twice weekly — the perioperative / injury stack. Thymogen covers the immune/infection-resistance arm while BPC-157 and TB-500 handle structural repair; mechanisms don't overlap.
Cycle Frequency#
Quarterly (every 8–12 weeks) is the upper end of what the community runs. Twice-yearly (spring/autumn) is the Khavinson-school default. There is no documented benefit to running blocks more frequently than quarterly, and continuous administration is specifically not how the compound was studied or registered. Between blocks, the lymphoid effects persist long enough that stacking blocks back-to-back offers diminishing returns on a compound that is already cheap and quiet by design.
Risks & mistakes
Common (most users)#
- Injection-site soreness or transient erythema — mild, typically resolves within an hour. Site rotation across abdominal quadrants and warming the reconstituted solution to room temperature before administration reduces incidence.
- Mild nasal irritation or sneezing (intranasal route) — expected with the 0.025% spray. Splitting the daily dose across 3–4 administrations rather than front-loading reduces mucosal fatigue.
- Transient headache — reported occasionally in the first 1–2 days of a 10-day block. Hydration and splitting the dose across morning/evening administrations typically resolves it; rarely requires protocol adjustment.
- Subjectively "quiet" response — not a side effect in the clinical sense, but the most common community complaint. Thymogen is a bioregulator, not a stimulant like Thymosin-α1. Expected markers (lymphocyte differential, hsCRP) shift over a 10-day block; subjective euphoria is not part of the profile.
Uncommon (dose-dependent or individual)#
- Injection-site welts or localized histamine response — more likely with under-reconstituted solution (higher concentration per microlitre) or rapid IM push. Reconstituting a 20mg vial to 2mL (10mg/mL) and drawing only 1 unit on a U-100 syringe keeps the bolus small.
- Transient lymph-node tenderness — occasionally reported in users running the higher 500µg–1mg Oglufanide-range protocols, consistent with the compound's action on lymphoid tissue. Self-limiting; the protocol calls for reducing to the 100–200µg range if it persists past 48 hours.
- Mild flu-like malaise in the first 2–3 days — seen in a minority of users, particularly when Thymogen is stacked with Thymalin in a combined block. Usually reflects cytokine rebalancing rather than infection. CBC with differential and hsCRP are the relevant bloodwork if verification is wanted.
- Hypersensitivity to excipients — more often attributable to mannitol or residual solvent in the lyophilized product than to the dipeptide itself. Switching vendor or batch usually resolves it.
Rare but serious#
- Autoimmune flare in subjects with subclinical or poorly controlled autoimmunity — because the compound drives T-cell maturation and CD4/CD8 rebalancing (Simbirtsev 1997), users with undiagnosed Hashimoto's, psoriatic arthritis, MS, or IBD have theoretical potential for symptom escalation. Warning signs: new joint pain, GI symptoms, skin flares, or thyroid swings during a block. Discontinue at first clear signal.
- Allergic reaction with systemic features — rare for a small endogenous-adjacent dipeptide, but possible with any parenteral peptide. Urticaria, facial swelling, or respiratory symptoms warrant immediate discontinuation.
- Theoretical antiangiogenic overlap with wound healing — α-Glu-Trp demonstrates VEGF inhibition at the higher Oglufanide-range doses (DrugBank DB05779). At the 100µg Cytomed-label range this is not clinically relevant, but protocols running 500µg–1mg alongside surgery or active granulation wounds should revert to the lower dose window.
Hard contraindications#
"Thymogen is an isolated fragment of thymopoietin-II and acts as a regulator of lymphoid system cell differentiation, exhibiting effects even at nanomolar concentrations." — Khavinson et al., Int J Mol Sci 2023
- Pregnancy and lactation — contraindicated per Cytomed registered labeling. No adequate developmental data exist.
- Active autoimmune disease — Hashimoto's in flare, active lupus, uncontrolled IBD, active MS, active psoriatic arthritis. A compound whose primary mechanism is driving T-cell differentiation is the wrong tool when the lymphoid system is already misfiring.
- Lymphoproliferative or hematologic malignancy — active leukemia, lymphoma, or myeloma. Contraindicated on mechanism.
- Known peptide hypersensitivity — prior anaphylactoid response to any thymic peptide or short-peptide bioregulator.
Gender considerations and stacking notes#
Thymogen is non-hormonal. It does not bind androgen, estrogen, progesterone, or glucocorticoid receptors, does not aromatize, does not suppress the HPTA, and does not carry virilization risk. No dose adjustment by sex is specified in the Cytomed registration data or the Oglufanide clinical record. The only sex-specific line is the pregnancy/lactation exclusion above.
PCT: none required. Thymogen can be administered during blast, cruise, bridge, or PCT without modifying the endocrine protocol — a clean fit alongside AAS, SARMs, or a finasteride/dutasteride hair stack. The compound's main stacking consideration is not endocrine but immunological: subjects already running Thymosin-α1 or high-dose Thymalin do not gain much from adding Thymogen in the same 10-day block, since the mechanisms overlap. Sequential rather than simultaneous use is the cleaner approach when running the broader Khavinson bioregulator protocol.
FAQ — Thymogen
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Research & citations
5 studies cited on this page.
Conclusion
Thymogen stands out as a precise, low-side-effect immune bioregulator — ideal for research targeting immune recovery, perioperative support, or deeper "reset" stacks in the bioregulator school. Its documented protocols are straightforward and well-tolerated when following label-aligned doses.
Key takeaways:
- Standard dose: 100–200 µg subQ once daily for 7–14 days, with cycles repeated 1–4× yearly
- Administered in short, discrete blocks rather than continuously; subQ is the dominant community route, with intranasal an option when available
- Pairs cleanly with Thymalin (10 mg/day), Epitalon, or BPC-157/TB-500 in stack protocols targeting immune recovery and wound healing
- Oral bioavailability is negligible — parenteral or intranasal is required for active research
- No PCT or hormonal overlap: not suppressive, safe for both sexes, and does not confound AAS protocols
- Side effect profile is minimal outside of hypersensitivity or excluded populations (autoimmune disease, pregnancy, lymphoproliferative states)
As part of a targeted immune or longevity regimen, Thymogen delivers a subtle but measurable boost in T-cell competence without the baggage of stronger immunostimulants or hormonal tools.