Cissus quadrangularis is a traditional medicine usually said to come from Ayurveda but appears to have a wide range of locations which have used it medicinally due to it growing in numerous locations. Its traditional usages are mostly catered around treating feminine disorders (menopause, libido, and menstrual disorders) or treating bones (increasing bone mass or accelerating fracture healing rates) which gives it the traditional name of the 'Bone Setter'; some other traditional usages are in regards to its supposed antiulcer properties, antihemhorroid properties, and pain relieving properties.
It is most frequently used by athletes, and the anecdotes of cissus seem to precede much of the science on the topic. It appears to be a very effective pain killer in rodent studies, but at this moment in time only one preliminary study has been conducted in humans; while it showed promise in athletes who experienced joint pain due to exercise (by reducing overall joint symptoms by about a third) it was still a lone study. More research is needed, but it seems promising as an alterative for joint pain in athletes since most joint health supplements do not have evidence in athletes (rather, most research is in osteoarthritis persons).
Although a potential complication in athletes is that preliminary rodent evidence suggests that cissus has sedative and muscle relaxing properties at high doses (active within 30 minutes of ingestion), suggesting that it might not make the best pre-workout supplement.
In regards to bone health, there are limited human reports of increased fracture healing rate which are poor quality of evidence due to not disclosing adequate methodology (ie. how they did the study) and not disclosing the source of the compound. Animal studies do show a great deal of promise in promoting bone growth, but this traditional claim also needs to be assessed in greater detail.
Finally, there are two human studies which suggest that cissus can be used as a fat loss agent but they have problems with their structure. In particular both studies are confounded with possible financial biases and since the supplements were consumed before meals with water (and cissus is known to have gum forming properties) while food intake was not measured making it wholly possible the observed effects could be due to reduced food intake, which is what happens when a gum (glucomannan, for example) is taken before a meal with water.
Overall, cissus has a good deal of promise in regards to joint and bone health in regards to athletic adults and menopausal women alike but requires a great deal more evidence to fully evaulate this promise.