When there is an overabundance of LDL, it is carried around the body more easily because it’s lighter (i.e., less dense). The HDL, therefore, doesn’t get properly distributed. As a matter of fact, HDL is necessary to keep LDL in check.
What does cholesterol do?
- Used in the production of hormones like cortisol, estrogen, and testosterone
- Makes vitamin D
- Is used by the liver to make bile that is used in digestion
- Forms and maintains cell membranes, serving as conduits for communication and electrical conductivity
- Used in the growth and maintenance of the brain (which is mostly fat)
Low levels of cholesterol throw everything off and can make you feel tired and sluggish.
What does high cholesterol do?
When LDL is too high, it sticks to the interior artery walls, reducing blood flow, and causing the heart to work harder than it should have to.
Without enough HDL–which removes LDL from the arteries–LDL accumulates, forming plaque. If arteries get too clogged–BAM–heart attack (or stroke) due to inadequate blood flow.
HDL works in synergy with LDL to balance cholesterol levels in the body. 
- LDL delivers cholesterol to cells in the body.
- HDL is involved in reverse cholesterol transport.
Why is low cholesterol bad?
In a nutshell, if cholesterol levels are too low, all the things it’s supposed to do don’t get done:
- Reduced libido
- Low vitamin D
- Liver and digestive issues
- Mood changes and fatigue
- Memory loss, a feeling of “foggy” brain, and increased risk of neurodegenerative disease
Is there an optimal level of cholesterol?
Yes and no.
Every person’s metabolism is different. One number may be high for one but normal (and healthy) for another–there is a genetic component to your body’s chemistry.