If you’re exploring fast-acting options for depression, the latest findings around nitrous oxide—often called laughing gas—are turning heads. A comprehensive meta-analysis suggests that nitrous oxide can lift depressive symptoms within hours of a single administration, though the effects appear to be mostly short-lived unless treatments are repeated. This is not presented as a cure, but as a potential rapid-acting tool that could complement existing therapies when used thoughtfully and under medical supervision.
Rationale and what the evidence shows
Depression affects more than 300 million people worldwide, arising from a complex mix of environmental, biological, and psychological factors that disrupt stress regulation and brain networks. Traditional antidepressants work for many, but a substantial number of individuals do not experience adequate relief. This gap has spurred interest in therapies that act more quickly to relieve symptoms, especially for those with treatment-resistant depression.
Nitrous oxide’s mechanism aligns with growing attention to the glutamatergic system. Ketamine’s rapid antidepressant effects helped shift focus toward NMDA receptor pathways, and nitrous oxide, a well-known NMDA receptor antagonist used during anesthesia, has shown similar rapid benefits in early research. The drug’s actions include modulating glutamate signaling, changing activity in brain networks linked to self-referential thought, and influencing dopamine and opioid systems. These biological targets position nitrous oxide as a promising candidate for further study as a fast-acting antidepressant.
What the studies looked at
The review gathered data from protocol papers, clinical trials, and exploratory studies to evaluate nitrous oxide for depression. It found eleven eligible studies: seven completed clinical trials (mostly randomized controlled designs) and four published protocols. Participants across these studies included individuals with major depressive disorder, treatment-resistant depression, and bipolar depression. Nitrous oxide was typically delivered at 25% or 50% concentrations via controlled inhalation for 20 to 60 minutes. Some studies used a single session, others employed repeated sessions weekly or twice weekly. Most efficacy estimates were driven by single-session 50% protocols.
What happens after a single dose
Across the trials, a single nitrous oxide session generally produced rapid improvements, with detectable relief within about two hours. In one early trial, a 60-minute exposure to 50% nitrous oxide yielded lower depression scores than placebo at two and 24 hours, and a subset of participants showed meaningful improvement (roughly 20% vs 5%), with some reaching remission within a day.
In another study focusing on treatment-resistant depression, improvement occurred within hours but tended to fade by the following week. A third trial found that nearly half of participants maintained some improvement after a week, particularly those who responded strongly initially. Bipolar depression results were mixed; in one comparison, nitrous oxide and the active control midazolam both reduced symptoms, but nitrous oxide produced greater early improvement, and certain brain-blood-flow patterns might help predict who benefits most.
Benefits appear stronger with repeated dosing
When multiple treatment sessions were used, the improvements tended to be larger and more durable. In several studies, accumulating benefits emerged within 24 to 48 hours after each session and continued to build over time. For example, eight sessions over four weeks produced substantial gains and higher remission rates than placebo. Dose differences mattered too: both 25% and 50% nitrous oxide reduced symptoms over a two-week period, but the higher dose offered stronger benefits while the lower dose caused fewer adverse effects like nausea and dizziness, suggesting a potential trade-off between efficacy and tolerability.
The most extensive trial to date explored weekly sessions over four weeks, finding steady, cumulative improvement and a higher likelihood of remission in the first week for those receiving nitrous oxide, with 50% concentration again delivering the strongest results.
What the combined data indicate
When results from multiple trials are pooled, nitrous oxide shows a clear antidepressant signal at both two hours and 24 hours after treatment. Early improvements are consistent across studies and exhibit low heterogeneity. However, the analysis did not demonstrate lasting benefits at one week without ongoing treatment, indicating that the main effects are short-term unless dosing is repeated.
Limitations and gaps
There are important caveats. The number of trials is small, and designs vary in delivery methods, comparators, and outcome measures. Long-term safety data, particularly for repeated use, remain incomplete. Potential publication bias and imperfect blinding in some trials could influence results, so caution is warranted in drawing firm conclusions.
Bottom line
Nitrous oxide appears to be a fast-acting antidepressant candidate that is generally well tolerated, with transient, milder side effects compared with placebo. The strongest and most durable benefits emerge with repeated dosing, suggesting a potential role as part of a broader treatment plan rather than as a stand-alone short-term fix. Large, longer-term, and mechanism-focused trials are needed to confirm these findings and to refine who is most likely to benefit.
Journal reference:
Gill, K., de Cates, A.N., Wiseman, C., Murphy, S.E., Williams, E., Harmer, C.J., Morales-Muñoz, I., Marwaha, S. (2025). Nitrous oxide for the treatment of depression: a systematic review and meta-analysis. eBioMedicine. DOI: 10.1016/j.ebiom.2025.106023. https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(25)00467-0/f
But here’s where it gets controversial: should nitrous oxide be embraced as a mainstream rapid-response antidepressant, or treated with extreme caution until long-term safety and real-world outcomes are clearer? And this is the part most people miss: the fastest-acting treatments may not translate into lasting relief unless integrated with psychotherapy, lifestyle changes, and personalized care. What’s your take—could nitrous oxide fill a critical gap for those with urgent need, or does the current evidence argue for restraint until more data accumulate? Share your thoughts in the comments.
