{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T09:41:12Z","timestamp":1786527672737,"version":"build-2736575974"},"reference-count":44,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T00:00:00Z","timestamp":1786320000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Brain Sci.","Brain Sciences"],"abstract":"<jats:p>Background\/Objectives: Ammonia inhalants, commonly known as smelling salts, are widely used in sport as an acute arousal strategy, yet their ergogenic value remains uncertain. This systematic review and three-level meta-analysis examined the acute effects of ammonia inhalation on physical performance and selected psychophysiological outcomes. Methods: Controlled human studies involving healthy adults, physically active individuals, or athletes were included when they compared ammonia inhalation with placebo, sham, or no-inhalation control conditions. Physical performance was the primary outcome, with heart rate and selected subjective responses analyzed as exploratory secondary outcomes. Results: Ten studies were included. The primary analysis showed no statistically significant effect of ammonia inhalation on overall physical performance (k = 47, g = 0.11, 95% CI [\u22120.06, 0.28]). Heart rate and subjective exertion\/fatigue were also not significantly affected. In contrast, subjective activation\/arousal increased significantly (k = 9, g = 0.73, 95% CI [0.43, 1.04]), although this finding was based on only two studies. Moderator analyses did not show consistent subgroup differences for performance type, training status, or comparator type, whereas sex-based differences were exploratory and based on limited evidence. Sensitivity analyses suggested that physical performance became significantly improved after removal of influential effects, and power\/explosive performance showed a possible benefit; however, these findings should be considered preliminary rather than confirmatory. Conclusions: Overall, ammonia inhalation appears to act primarily as a brief arousal stimulus rather than a consistent ergogenic aid. Potential benefits may depend on task demands, with explosive or repeated high-intensity tasks appearing more plausible targets than maximal strength or precision-based skills. Current evidence remains limited by small samples, heterogeneous protocols, and low certainty.<\/jats:p>","DOI":"10.3390\/brainsci16080849","type":"journal-article","created":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T16:35:16Z","timestamp":1786379716000},"page":"849","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Smelling Salts or Smoke and Mirrors? Acute Ammonia Inhalation, Arousal, and Physical Performance: A Systematic Review and Meta-Analysis"],"prefix":"10.3390","volume":"16","author":[{"given":"Shenghui","family":"Liu","sequence":"first","affiliation":[{"name":"Faculty of Sports and Exercise Science, Universiti Malaya, Jalan Universiti, Kuala Lumpur 50603, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaohan","family":"Fan","sequence":"additional","affiliation":[{"name":"Faculty of Sports and Exercise Science, Universiti Malaya, Jalan Universiti, Kuala Lumpur 50603, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-3876-1961","authenticated-orcid":false,"given":"Zhiyuan","family":"Tan","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Blagoja Parovi\u0107a 156, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-8260-2145","authenticated-orcid":false,"given":"Jinfa","family":"Gu","sequence":"additional","affiliation":[{"name":"School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qing","family":"Huang","sequence":"additional","affiliation":[{"name":"Faculty of Sports and Exercise Science, Universiti Malaya, Jalan Universiti, Kuala Lumpur 50603, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hansen","family":"Li","sequence":"additional","affiliation":[{"name":"School of Physical Education, Sichuan Agricultural University, Ya\u2019an 625014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2310-6468","authenticated-orcid":false,"given":"Lewis J.","family":"Macgregor","sequence":"additional","affiliation":[{"name":"Centre for Research & Innovation in Sport, University of Stirling, Stirling FK9 4LA, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hengzhi","family":"Deng","sequence":"additional","affiliation":[{"name":"Faculty of Sports and Exercise Science, Universiti Malaya, Jalan Universiti, Kuala Lumpur 50603, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"706","DOI":"10.1177\/19417381231217341","article-title":"Ammonia Inhalants: Use, Misuse, and Role in Sports Performance","volume":"16","author":"Bender","year":"2024","journal-title":"Sports Health"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1519\/SSC.0000000000000630","article-title":"Effects of ammonia inhalants in humans: A review of the current literature regarding the benefits, risks, and efficacy","volume":"43","author":"Malecek","year":"2021","journal-title":"Strength Cond. 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