This ad page from Ciao! Magazine is interesting on several levels.  Given the presence of full frontal nudity and the dildo ads, we can say it was probably well into the 1970's.  It also shows a striking contrast in the advertising styles of two giants of the physique photo business, Western Photography Guild and AMG/Bob Mizer.  Don Whitman of WPG was a real artist when it came to photography, but his ads, including this one, tended to be cluttered with too many pictures which lessens their impact on the casual viewer.  Mizer, on the other hand, went for fewer and bolder images.