Another week, another medical story going viral on TikTok. Following on from the grand hit that was "here's how you splint", people on the site are sharing a "hack" that supposedly stops your gag reflex.
There's no need to go blue, it's perfectly possible this is because everyone is doing an awful lot of COVID-19 tests right now, which, if you're anything like us, can make you gag horribly.
In one video that's circulating at the moment, user gemmalawson57 demonstrates the technique, while a voiceover explains it.
"OK guys, so get your left hand and put your thumb in a fist," the unknown voice narrates. "Squeeze as hard as you can, and after five seconds get your right index finger and press it on your chin. Now count to five."
"OK, now get your right thumb and right index finger and squeeze between the skin between your left thumb and your left index finger. Squeeze it for five seconds. OK, now you've got rid of your gag reflexes, thank me later."
It's by no means the first time the "hack" has been shared on the site, with others doing similar tricks back in 2020.
So, is there anything in it? Well, actually it looks positive – though a few of the steps TikTokers are doing are weird and unnecessary extras, and they could do with moving to a slightly different spot to apply pressure.
Several studies have looked into the matter. Dentists have a particular interest in stopping the gag reflex, given that their work requires them to be in what is known as the "spew zone". First, a study published in the Journal of the American Dental Association saw pressure applied to the palms of a small group of volunteers, before they received dental treatment.
"Thirty-six neurologically intact subjects underwent a series of gag reflex trials (baseline, sham and treatment)," the team wrote in the paper. "The authors developed a hand pressure device for subjects to wear, which provided a consistent force, and they described a gag trigger point index (GTPI) scale. On the basis of the GTPI, they divided subjects into a hypersensitive group and an expected-sensitivity (control) group."
They found that when pressure was applied to the palm, the gag reflex moved backward, further into the patients' mouths – if a patient would gag with something not very far into their mouth, the point at which they started gagging would be further back after pressure was applied. They concluded that "application of the pressure point during dental procedures would decrease the likelihood of triggering a gag reflex," though they stressed more study was needed.
Distraction is an effective method of dampening the gag reflex, so it could be that this is what happened, or that there was a placebo effect in play.
However, others have tried to account for this by applying pressure to multiple regions on a number of subjects. Published in the National Center for Biotechnical Information, the study applied pressure to "the P-6 Neikuan acupuncture point, located on the wrist, has been used in the Far East for thousands of years for its anti-nausea and anti-anxiety properties"
They also applied pressure to dummy sites.
"The P-6 point has remarkable anti-gagging effects if stimulation is applied correctly," they concluded. "Clinicians may apply thumb pressure at the P-6 point to achieve some effect, although this is not as effective as acupuncture. Nevertheless, a substantial percentage of gagging patients would be able to go through dental procedures without gagging when the P-6 point is stimulated."
The place where the pressure is applied, however, is on the wrist.
A further study looked at laser stimulation (as an alternative to acupuncture) to the point above the chin, also pressed in the viral videos above. Again, there was a significant reduction in the gag reflex of patients compared to placebo. What we don't know, annoyingly, is why, though they do have theories.
"The mode of action in controlling gag reflex through acupuncture is not fully understood. It covers the spectrum of the gag reflex from the mild end of nausea, to the severe end that culminates in vomiting," the team write in the paper, published in Nature.
"It has been shown that acupuncture accelerates the synthesis of [serotonin] 5-HT, and it is likely that the serotonin mechanism takes part in the control of the gagging reflex."
In conclusion: TikTok, you are likely onto something on this one, but you can probably stop pinching your skin between your thumb and finger, and instead apply pressure to your wrist at site P6. There's probably a placebo effect involved too, but who cares if it stops you puking during Covid tests.