Lost libido, ability to have orgasm, and natural lubrication (and inability to lose weight, zero energy, focus, etc, etc) in '94 following mastectomy and chemo. Multitude of drs no help. During hospitalization for pancreatitis in Feb. '13 (20 days), I got b 12 injections for 7 days. Drs later decided I wasn't really deficient, but within days, I had surge of libido. Over next 6 months lost 50 lbs, rediscovered muscle and concentration, etc. Effect started dropping off. Taking oral 5000 mcg but weight loss hasn't picked up. Just started using patch. Libido is improving again. Orgasm too. Following paleo diet (stopped chronic sinusitis and psoriasis). Using many supplements recommended here including mg (great for restless legs but no effect on libido), maca , vit d, vco, Apple Cider Vinegar and more. They helped with many things but not libido. Will continue experimenting. Definitely feel b 12 caused my turn around. Wish my various drs were less hidebound. Shame to spend 20 years begging for help and one simple blood test revealed it.