Very small.
They are prepackaged, sterile, and single use.
Each acupuncture point has a unique sensation when it is pinned. The most common sensation is a dull and heavy feeling called de qi sensation, meaning, the arrival of qi/energy.
If there is any pain or you find the sensation uncomfortable you should let the acupuncturist know so they can remove or adjust the pin.
I am often asked if acupuncture hurts and the answer isn’t a straightforward yes or no.
Fertility, energy, and mental health treatments usually don’t have any strong sensations. Neck pain, low back pain, and injuries usually have strong sensations while the pins are being placed.
There can be discomfort or pain for a minute or two. After that, there is usually a strong de qi sensation but there isn’t any pain.
Acupuncture doesn’t need to hurt to be effective.