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The details that actually shape the buying decision.
Evidence, risk, regulatory flags, cost, and vendor coverage — side by side, without affiliate spin.
01· Subject
Dihexa
Preclinical procognitive/synaptogenic compound acting via HGF/c-Met axis. No long-term human safety data.
Tier Cextreme risk
02· Subject
Semax
ACTH fragment analogue with preclinical neurotrophic signaling and limited clinical stroke/cognition data.
Tier B-Cmed-high risk
01 · At a glance
| Decision factor | Dihexa | Semax | Selank |
|---|---|---|---|
| Primary fit | cognitive & neuroprotection research where you want a clear starting point | cognitive & neuroprotection and anxiety & mood comparisons | cognitive & neuroprotection and sleep & relaxation comparisons |
| Evidence | Tier C | Tier B-C | Tier B-C |
| Risk | extreme | med-high | med-high |
| Experience level | advanced | intermediate | intermediate |
| Budget tier | premium | mid | mid |
| Administration route | oral, subcutaneous | intranasal | intranasal |
02 · Use case & timing
| Decision factor | Dihexa | Semax | Selank |
|---|---|---|---|
| Goal fit | Cognitive & Neuroprotection | Cognitive & Neuroprotection, Anxiety & Mood | Cognitive & Neuroprotection, Sleep & Relaxation, Anxiety & Mood |
| What users compare it for | Preclinical synaptogenesis and cognitive enhancement signals. | Neurotrophic signaling; cognitive/neuroprotection narratives from Russian/EE clinical literature. | Anxiolytic/calm focus effects reported in limited clinical settings. |
| Onset timeline | Animal cognitive endpoints vary by study design; no clear consumer timeline. | Gene expression changes within hours (animal); clinical stroke outcomes are longer-horizon. | Some rapid responders described in clinical abstracts, but not broad RCT-grade evidence. |
| Main tradeoff | Potential upside comes with much more safety and screening caution than lower-risk alternatives. | Evidence and product availability can still be uneven, so documentation matters more than hype. | Evidence and product availability can still be uneven, so documentation matters more than hype. |
03 · Safety & restrictions
| Decision factor | Dihexa | Semax | Selank |
|---|---|---|---|
| Adverse effects | No long-term human safety data; explicitly flag this gap. | Immunogenicity/impurity concerns (FDA); limited Western safety framing. | Limited Western regulatory data; higher scrutiny warranted. |
| Contraindications | No data. | No established label. | No established label. |
| Interaction notes | Unknown. | Unknown; avoid claiming synergy with SSRIs/benzodiazepines without data. | Animal diazepam interaction explored; do not translate to human guidance. |
| Regulatory status | Not approved | Not approved | Not approved |
| FDA flag | FDA status unclear | FDA compounding caution | FDA compounding caution |
| WADA status | Not listed | Status unclear | Status unclear |
04 · Age & monitoring
| Decision factor | Dihexa | Semax | Selank |
|---|---|---|---|
| Supported age ranges | No age guidance yet | 25-34, 35-44, 45-54, 55-64, 65+ | No age guidance yet |
| Life-stage note | Not yet documented | Usually discussed for adult cognitive or recovery support rather than youth-oriented performance enhancement. | Not yet documented |
| Monitoring burden | Not specified | Not specified | Not specified |
| Follow-up cadence | Not yet documented | Not yet documented | Not yet documented |
05 · Cost & sourcing
| Decision factor | Dihexa | Semax | Selank |
|---|---|---|---|
| Typical cycle cost | No reliable estimate yet | €13.76 | €20.64 |
| Estimated monthly cost | No reliable estimate yet | €27.52 | €27.52 |
| Cost confidence | No estimate | High confidence | High confidence |
06 · Before you buy
| Decision factor | Dihexa | Semax | Selank |
|---|---|---|---|
| Tracked vendor listings | 0 listings | 3 listings | 3 listings |
| Sourcing note | No tracked product page yet, so sourcing takes more manual review. | Product format varies by listing, so double-check route, concentration, and presentation. | Product format varies by listing, so double-check route, concentration, and presentation. |
| Stack-friendly? | Usually stack-friendly | Usually stack-friendly | Usually stack-friendly |
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