This may explain my unusually dense bones
HU Scientists Develop Prototype Drug to Prevent Osteoporosis Based on Cannabinoids Produced by Body
Substances made in the body called endocannabinoids are composed mainly of fatty acids which were discovered during the last 15 years. (The fatty acid anandamid was discovered by Prof. Mechoulam in 1992.) These materials, which are produced mainly in the brain, are present also in the bone and other tissues and have similar effects to those of the active components in hashish and marijuana, produced from the cannabis plant.
Personally, I wouldn't go around bragging that Pot turned you into a dense guy, even if you now have scientific proof.