Acupuncture is certainly a perplexing practice. Animal bodies do not appear to have physical correlates to the meridians thought to give rise to the acupuncture points. However, instruments exist that localize the points by measuring a change in impedance. But what does that come from?

[e-jar.org]

Limb regeneration in insects and amphibians makes use of similarly invisible fields or gradients. Transplanted limbs that are rotated disrupt these 'morphogenic' gradients so as to produce supernumerary limbs. How does that work? Some mechanisms have been proposed...

The point being that medical science evolves and works to know more, knowing it doesn't know everything.

These debunkers keep asking for a mechanism. The problem is that, like the acupuncturists, they start with the answer they BELIEVE and contrive their own cherry-picked evidence or debunking to back up their view. That's what makes debunkers members of the debunking cult.

Per Google: "Acupuncture points are believed to stimulate the central nervous system. This, in turn, releases chemicals into the muscles, spinal cord, and brain. These biochemical changes may stimulate the body's natural healing abilities and promote physical and emotional well-being."

Perhaps acupuncture is nothing more than stimulating the release of endorphins, and indeed, naloxone has been shown to block the effects of acupuncture. But if acupuncture is a scam, what is naloxone doing?

[pubmed.ncbi.nlm.nih.gov]

Also from Google: "Acupuncture can be used on all species of animals, and has documented efficacy on a wide range of species, including elephants, cattle, horses, dogs, cats, monkeys, and rabbits. However, it tends to be more frequently used in companion animal species such as the horse, dog and cat."

@AnneWimsey, @Lorajay, @barjoe