Although any internet search for anything penis-related results in a deluge of useless adverts and claims, there are genuine studies which have concluded that traction devices have an effect.
This study notes an average curvature change of 33% from a group trying the FastSize Penile Extender, this study found a lower proportion of success, with only 54% of participants responding to treatment of traction and verapamil injections, but those who responded achieved a 26 degree correction on average, which is not insignificant.
All of these studies also find at least some positive affect of traction therapy for curvature.
Caveats:
- Two of the studies mentioned refer specifically to the FastSize device in their titles, which could indicate that they were in fact funded by FastSize themselves. Consider these results critically.
- Only one study significantly expressed the long term affects after cessation of therapy. Whilst this study showed a similar achievement of correction immediately after the 6 month study period, results varied after cessation of traction for a further 6 months, with some participants reporting a return to their previous state. This could suggest that the affects of penile traction for correcting curvature are temporary or sometimes temporary, and that permanent results could only be achieved with long term or even permanent use of traction. This same study also notes that long term results were of minimal difference, but that the selection of participants may have been a factor in this.
The overall conclusion of the studies mentioned is that traction makes some difference, but no study could conclude a definitive and extensive long term result - the possibility of which seems more hit and miss according to the one study that addressed it.
A Google Scholar search for 'Penile traction curvature' yielded slightly over 2 thousand results, so further literature is available for review, and a proper literature review may yield firmer and more definite results.