Complex sentence: Some patients may be more resistant to the effects of anesthetics than others, women need more anesthetic than men, there are several possible reasons for this, e.g. less alcohol consumption, female hormones, different fat distribution in the body, but nobody has researched this.
Split into simpler sentences: Some patients may be more resistant to the effects of anesthetics than others; women need more anesthetic than men, for example. There are several possible reasons for this: lower alcohol consumption, female hormones, differential fat distribution in the body, but nobody has researched this.