Jamrasi, Parivash, Seo, Ji-Won, Sung, Yunho et al. · Journal of microbiology and biotechnology · 2026 · DOI
A new study tested whether a supplement made from deer velvet extract (called YC-1101) could reduce fatigue in 100 adults with chronic fatigue syndrome. Over 8 weeks, people taking the supplement reported improvements in tiredness and ease of fatigue compared to those taking placebo, and they also showed better exercise capacity. However, the study is very recent (2026) and peer-review status is unclear, so these findings need confirmation in other research before drawing firm conclusions.
This RCT provides the first clinical-trial evidence that a deer velvet extract may be associated with improvements in self-reported fatigue severity and exercise tolerance in CFS patients. The study also measured objective biomarkers (lactate, exercise endurance), which is important for understanding whether subjective fatigue improvements correlate with measurable physiological changes. If confirmed in independent replication, this finding could offer an evidence-based supplement option for a patient population with limited pharmacological treatments.
This study does not establish the biological mechanism by which YC-1101 might reduce fatigue or improve exercise tolerance. It does not generalise beyond the 100 participants studied or rule out publication bias / selective reporting of outcomes. Peer-review status is unknown, so the robustness of the statistical analysis and case definition cannot yet be verified. The 8-week timeframe does not reveal whether benefits persist beyond the intervention period.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Jamrasi, Parivash, Seo, Ji-Won, Sung, Yunho, Kim, Donghyun, Han, Sanghyuk, Kim, Sowoon, et al. (2026). Efficacy and Safety of Enzyme-Derived Deer Velvet Extract Supplementation on Adults with Chronic Fatigue: a Randomized, Placebo-Controlled, Double-Blind Trial.. Journal of microbiology and biotechnology. https://doi.org/10.4014/jmb.2601.01055
BibTeX
@article{mecfsatlas-jamrasi-2026-efficacy-safety,
author = {Jamrasi, Parivash and Seo, Ji-Won and Sung, Yunho and Kim, Donghyun and Han, Sanghyuk and Kim, Sowoon and Kim, Chaewoon and Li, Xinxing and Park, Hyun-Je and Song, Aeri and Baek, Sinhwa and Jeong, Jeongho and Song, Wook},
title = {Efficacy and Safety of Enzyme-Derived Deer Velvet Extract Supplementation on Adults with Chronic Fatigue: a Randomized, Placebo-Controlled, Double-Blind Trial.},
journal = {Journal of microbiology and biotechnology},
year = {2026},
doi = {10.4014/jmb.2601.01055},
note = {PubMed: 42487402},
url = {https://www.mecfsatlas.com/evidence/jamrasi-2026-efficacy-safety},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-08-24. https://www.mecfsatlas.com/evidence/jamrasi-2026-efficacy-safety
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