Forest bathing is scientifically proven to significantly boost immune function?

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The Reel accurately reports early pilot studies on forest bathing, but overstates preliminary immune marker changes into definitive claims about countering major diseases. Dr. Qing Li's research demonstrated that 3-day forest walks increased natural killer cell activity in small study groups of 12 subjects compared to urban walks. However, systematic reviews in Environmental Health and Preventive Medicine note that small sample sizes and short-term designs prevent drawing broad conclusions about preventing or treating clinical conditions like cancer and strokes. Dr. Li began his forest medicine research in 2005, rather than 30 years ago.

4 claims checked
8 sources
Checked 10 Nov 2026
Main source: Forest bathing enhances human natural killer activity and expression of anti-cancer proteins - PubMed

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The Reel we checked

@andyyjiang_

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What we checked

In a study by Dr. Qing Li, 12 people walking in a forest for three days had their natural killer (NK) cell activity increase by almost 50%.“Twelve healthy male subjects, age 37–55 years, were selected with informed consent from three large companies in Tokyo, Japan.”Forest bathing enhances human natural killer activity and expression of anti-cancer proteins - PubMed + 1 more

A control group walking the same amount in a city showed no change in NK cell activity.“Prior to the forest visit, in mid-May 2006, 11 of the same 12 subjects participated in a city tourist visit”Effect of forest bathing trips on human immune function - PMC + 1 more

Trees like pine, cedar, and cypress release airborne organic compounds called phytoncides.“Forest bathing, a traditional Japanese practice, offers psychological and physiological benefits through phytoncide exposure.”Phytoncides and immunity from forest to facility: A systematic review and meta-analysis - ScienceDirect + 1 more

The increase in NK cell activity after forest walking lasted up to 30 days.No reliable source found for this yet.

What the Reel doesn't tell you

While small-scale pilot studies showed short-term increases in natural killer cell activity after forest walks, systematic medical reviews emphasize that small sample sizes prevent proving that forest bathing counters severe diseases like cancer or strokes.
Literature reviews by Dr. Qing Li note that while preliminary studies show promising physiological responses, existing research mostly involves small sample sizes and short interventions, requiring larger controlled trials to establish clinical preventive effects.
Studies conducted by Dr. Qing Li between 2005 and 2010 found that three-day forest bathing trips increased natural killer cell activity and anti-cancer proteins in small groups of 12 subjects compared to urban walks, with effects persisting for over a week.

Short version

⚠️ MISLEADING 👉 Early pilot studies show forest walks temporarily boost immune markers, but there is no proof forest bathing prevents or counters major diseases like cancer and strokes. 👉 Dr. Qing Li found increased natural killer cell activity in groups of 12, but systematic reviews note small sample sizes prevent broad clinical conclusions. 📰 Sources: Greenmedinfo, Nms 🔎 Full check: send this Reel to @checkthis.chat