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Does Cracking Your Knuckles Cause Arthritis? The Truth
Someone has definitely told you to stop “or you'll get arthritis.” One doctor cracked the knuckles of a single hand for 50 years to test exactly that. Here's what he — and the wider research — found.
The short answer: no — it doesn't cause arthritis
Quick answer
No. There is no good evidence that cracking your knuckles causes arthritis. Studies comparing habitual knuckle-crackers to non-crackers find no difference in arthritis rates, grip strength, or hand function. The most famous test: Dr. Donald Unger cracked the knuckles of one hand twice a day for over 50 years and left the other hand alone — and found no difference between them. A larger 2017 review likewise found knuckle cracking doesn't cause arthritis, joint swelling, or deformity. It's a harmless habit for almost everyone.
This is one of the most thoroughly debunked “your parents were wrong” health myths — and Dr. Unger literally won an Ig Nobel Prize for the 50-year experiment that helped settle it.
So what is that popping sound?
Quick answer
The pop is gas, not bone. Your joints contain synovial fluid with dissolved gases. When you stretch or bend the joint, the pressure drops and a gas bubble rapidly forms (a process called cavitation) — that's the cracking sound. It's not bones grinding or cartilage tearing. After cracking, it takes about 20 minutes for the gas to redissolve, which is why you can't immediately re-crack the same knuckle. This bubble formation is harmless and unrelated to joint damage or arthritis.
So the noise that sounds alarming is just physics in your joint fluid. It doesn't mean anything is wearing out. Like other persistent “facts” — see does shaving make hair grow back thicker? — the scary version just isn't supported.
The honest caveats
Quick answer
Mostly no, with small nuances. Some studies have noted that very frequent crackers may have slightly reduced grip strength or mild hand swelling, though findings are inconsistent and not linked to arthritis. Cracking shouldn't hurt — if a joint is painful, swollen, stiff, or the popping is new and accompanied by pain, that's worth seeing a doctor about, because that points to a possible injury or joint issue, not the cracking itself. Forcing a joint hard enough to injure it is the real risk, not the routine pop.
Bottom line: a painless knuckle crack is fine. Pain is the signal to pay attention to — the habit itself isn't causing arthritis.
The evidence base, cited
Research consistently finds no link between knuckle cracking and arthritis: habitual crackers show similar hand function and grip to non-crackers, Dr. Donald Unger's 50-year single-hand self-experiment found no difference, and a 2017 review found no arthritis, swelling, or deformity from cracking (Harvard Health; Mayo Clinic). The sound is gas cavitation in synovial fluid.
Sources: Harvard Health | Mayo Clinic. General information, not medical advice.
The bottom line
Does cracking your knuckles cause arthritis? No — the evidence, including a 50-year self-experiment, is clear. The pop is just gas forming in joint fluid, not damage. Crack away if it's painless; only pain, swelling, or stiffness is worth a doctor's look.
This article is general information, not medical advice.
GiftedPicks Editorial Team
Product Research & Editorial
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