Most who feel fatigued, sick, run down, no energy, etc... for no reason (medical problems should, of course, be ruled out) feel better after a detox. 

Accumulation of heavy metals in the body is another reason many people detox. If you've worked in atmospheres with chemicals, such as in at a service station, in a beauty salon, or as a painter, you may have heavy metal poisoning.   Heavy metal levels can be tested medically through hair analysis.  

If you've worked in construction work for any length of time it is also a good idea to detox regularly.

Some heavy metal symptoms include:-