VIR-8, Hypoxen and comparators under hypoxia with heat or cold
E. B. Shustov, Yu. V. Fokin, S. L. Lyublinskiy, O. V. Alimkina, A. E. Kim, D. Yu. Ivkin, E. L. Matveenko, A. S. Ivkina, G. A. Plisko, M. A. Poveryaeva · 2021 · Biomeditsina. 17(1):57–69
Published 2021-03-10.
Related evidence maps: Sports performance ↗ · Military & occupational ↗
Reported findings and study design
VIR-8 extended swimming under hypoxia plus cold (12.5±1.3 vs 4.5±0.4 seconds) but did not improve swimming under hypoxia plus heat (16.8±1.5 vs 16.9±2.3 seconds).
Male outbred mice, 18–21 g; 10 randomized per group; loaded swim at 5% body mass after sodium nitrite-induced hemic hypoxia
Dose, route and schedule
VIR-8: 5 mg/kg rectally in 0.5 mL starch vehicle daily for 5 days. Hypoxen: 50 mg/kg orally by gavage once, 1 hour before testing. Sodium nitrite: 50 mg/kg intraperitoneally for hemic hypoxia. Main swim load: 5% body mass.
Protocol source ↗ · Original publisher issue PDF, printed pp. 57–69; methods and Tables 1 and 3 checked
| Measure | Result | Comparison, timing and statistics |
|---|---|---|
| VIR-8 · hypoxia plus cold | 12.5±1.3 versus 4.5±0.4 s; +178% | Table 3; compared with stressed control, n=10 per group · p=0.0002 |
| VIR-8 · hypoxia plus heat | 16.8±1.5 versus 16.9±2.3 s; 0% reported | Table 1; compared with stressed control · p=0.99 |
| VIR-8 · hypoxia at normal temperature | 29.8±4.2 versus 24.4±2.7 s | Same thermoneutral series is displayed in Tables 1 and 3. Do not count it twice. |
| Hypoxen · hypoxia plus cold | 10.0±0.9 versus 4.5±0.4 s; +120% | Table 3; compared with stressed control · p=3×10⁻⁵ |
| Hypoxen · hypoxia plus heat | 22.7±3.5 versus 16.9±2.3 s; +34% | Table 1; nonsignificant versus stressed control · p=0.18 |
| Other arms · directional reversal | Flamenco 50 mg/kg: −37% in heat, +111% in cold | Different comparator preparation; not a VIR-8 result. Low-dose heat comparison p=0.02; cold p=2×10⁻¹² as printed. |
| Safety and sequence | No human safety study or sequence-level characterization reported | The designation VIR-8 is insufficient to infer constituent peptides. |
Tables 1 and 3 · forced swimming across stress conditions
| Group | Hypoxia, normal temperature (s) | Hypoxia + heat (s) | Heat effect vs control | Hypoxia + cold (s) | Cold effect vs control |
|---|---|---|---|---|---|
| Intact comparator | 72.6±7.0 | 63.5±7.9 | — | 5.6±0.7 | — |
| Stressed control | 24.4±2.7 | 16.9±2.3 | Reference | 4.5±0.4 | Reference |
| MioActive Sport | 24.8±2.7 | 16.9±1.3 | +2%; p=0.99 | 18.4±1.5 | +308%; p=2×10⁻¹¹ |
| VIR-8 | 29.8±4.2 | 16.8±1.5 | 0%; p=0.99 | 12.5±1.3 | +178%; p=0.0002 |
| Flamenco 50 mg/kg | 19.3±1.5 | 10.6±0.9 | −37%; p=0.02 | 9.5±1.1 | +111%; p=2×10⁻¹² |
| Flamenco 75 mg/kg | 21.5±5.0 | 14.6±1.8 | −14%; p=0.43 | 12.9±0.8 | +187%; p=2×10⁻¹⁰ |
| Flamenco 250 mg/kg | 20.7±2.8 | 34.4±4.7 | +104%; p=0.003 | 6.9±1.0 | +53%; p=2×10⁻¹² |
| Trimetazidine | 22.7±11.1 | 87.3±18.2 | +418%; p=0.01 | 6.7±0.3 | +49%; p=2×10⁻¹⁷ |
| Hypoxen | 30.1±4.3 | 22.7±3.5 | +34%; p=0.18 | 10.0±0.9 | +120%; p=3×10⁻⁵ |
M±m and reported p-values transcribed from the article. Percentages are the authors’ reported changes relative to stressed controls, not comparisons between active arms. The intact groups do not receive hemic hypoxia; the displayed first column represents the relevant normothermic baseline.
Retain the neutral heat result alongside the positive cold result. The model examines hemic hypoxia during temperature stress, not altitude acclimatization or actual outdoor work. The distinct products cannot be ranked as equivalent-dose interventions.
Source for the extracted data ↗ · Checked 2026-11-08
Molekul summary of the linked publication. Educational information, not medical advice. Seek qualified healthcare help for medical conditions.
Methods, limitations & source review
Study limitations
- Each comparator used its own formulation, dose and schedule.
- The short mouse swim endpoint cannot establish human cold tolerance, prevention of heat injury or improved sports performance.
- The paper does not identify VIR-8 sequences or establish an identity match with PPK-V.
Publication counts are not counts of independent trials. Reviews, translations and reports sharing participants may overlap. Findings apply to the studied preparation, population and endpoints.
Document format: Original publisher issue PDF, printed pp. 57–69; methods and Tables 1 and 3 checked
Review depth: Reported methods, results and evidence limitations
Source access and review scope
Original publisher issue PDF, printed pp. 57–69; methods and Tables 1 and 3 checked
Recorded source-check date: 2026-11-08. This date does not imply a completed systematic review.
Source type: Original journal article
Citation and original source
Original source: E. B. Shustov, Yu. V. Fokin, S. L. Lyublinskiy, O. V. Alimkina, A. E. Kim, D. Yu. Ivkin, E. L. Matveenko, A. S. Ivkina, G. A. Plisko, M. A. Poveryaeva. VIR-8, Hypoxen and comparators under hypoxia with heat or cold Biomeditsina. 17(1):57–69 2021.
Molekul research summary: https://molekul.io/research/shustov-vir8-temperature-2021. Cite the original publication for its findings and this page when referring to Molekul’s summary or evidence appraisal.
Bibliography entryRelated compound profiles
VIR-8
A named Mobitek-M polypeptide complex tested in mice during combined oxygen and temperature stress. The article supplies a route and dose but does not disclose sequences, molecular-weight fractions or an identity match to PPK-V.
Hypoxen / Olifen
A synthetic polyphenolic preparation studied in hypoxia, environmental stress, exercise and cellular-energy metabolism. Human findings are limited, and laboratory effects depend on experimental conditions.