Is "Laughter Is the Best Medicine" Actually True?
The phrase turns up on mugs and posters, which makes it easy to dismiss. Yet unlike most feel-good slogans, this one has a real, if modest, research literature behind it. The honest summary is that laughter is not medicine in the sense of a treatment that cures disease, but there is credible evidence that regular, genuine laughter is good for the body and mind. Here is what the science supports, and where the claims outrun the data.
A Caveat About the Evidence
Before the findings, a note on quality. Much laughter research involves small samples, short-term measurements, and outcomes that are hard to isolate from general good mood, social contact, or exercise-like exertion. Reputable health institutions treat the benefits as promising and low-risk rather than proven cures. So read what follows as "research suggests," not "science has established." That framing is not a hedge; it is how the evidence actually stands.
The Heart and Blood Vessels
One of the better-studied areas is vascular function. Research summarised by health institutions suggests that hearty laughter is associated with short-term improvements in the way blood vessels dilate, the endothelium relaxing in a manner loosely comparable to light aerobic activity, with the effect lasting on the order of tens of minutes. Distressing or stressful stimuli tend to have the opposite effect.
This is a genuine and welcome finding, but it needs proportion. No researcher is suggesting comedy replaces exercise. What the data support is a smaller claim: regular genuine laughter appears to be a mild positive for cardiovascular health, layered on top of — not instead of — the basics like movement, sleep, and diet.
The Immune System
Laughter's effects on immune markers have been studied for decades, notably in work associated with researchers at Loma Linda University. This line of research reports that mirthful laughter is associated with changes in immune-related measures — including activity of natural killer cells and levels of certain antibodies — and with reductions in stress hormones that can suppress immune function.
An intriguing thread in this work is anticipation: simply expecting to laugh, before the funny thing arrives, appears to begin shifting stress-hormone levels. These are real, measured effects, but they are markers rather than proof of fewer illnesses, and the studies are generally small. The reasonable takeaway is that laughter nudges immune-related measures in a favourable direction.
Pain Tolerance
Some of the most quotable laughter research comes from the University of Oxford. A 2011 study led by evolutionary psychologist Robin Dunbar found that sustained, breathless "belly" laughter raised participants' pain thresholds, with the likely mechanism being the release of endorphins — the same class of neurochemicals linked to the runner's-style effects of vigorous exercise.
The crucial detail is intensity. Polite chuckles and social smiles did not produce the effect; the physical, involuntary, gasping kind of laughter did. That points to a practical rule: the laughter that seems to do the body good is the loud, undignified sort, not gentle amusement.
Stress and Cortisol
Chronic stress, and the sustained elevation of the hormone cortisol that comes with it, is linked to well-documented harms over time, from disrupted sleep to cardiovascular strain. Multiple studies and clinical summaries report that laughter is associated with reduced cortisol and a general relaxation response in the aftermath of a good laugh.
Of all the findings, this may be the most relevant to everyday life. Stress is a constant for many adults, and its costs accumulate quietly over years. Anything low-risk that reliably interrupts the stress response — a good laugh among them — is worth building into a routine.
So What Does the Saying Get Right?
Pulling the threads together, the evidence supports a specific, modest reading of the cliché:
That is genuinely encouraging, because the goal is not to feel relentlessly cheerful — an exhausting prospect — but to create conditions for occasional, uncontrollable hilarity. Comedy that actually breaks your composure, playful group games, and the kind of nonsense that leaves you gasping are exactly the sort of thing worth seeking out on purpose.
The Responsible Bottom Line
Laughter is not a cure, and anyone selling it as one is overreaching. But it is free, low-risk, socially bonding, and backed by a real if imperfect body of research suggesting benefits for the heart, immune markers, pain tolerance, and stress. If you are choosing between another doomscroll and something that makes you laugh out loud, the science quietly sides with the laugh. Just keep it in perspective — and keep your regular checkups too.