Extreme side effects of Cellucor C4 Extreme include compartment syndrome, as reported by HealthTap and ABC News. In severe abdominal cases, compartment syndrome can require surgery, including liver transplant, and may promote systemic body inflammation, ascites, abdominal bleeding and death, according to WebMD.
Acute compartment syndrome is usually the result of injury and develops rapidly within hours or days of injury. Less common is chronic compartment syndrome, which arises over the course of days or weeks due to regular, vigorous exercise. Certain drugs including the dietary supplement creatine, which is the primary ingredient of C4 Extreme, are noted by Mayo Clinic to increase the risk of chronic compartment syndrome due to the resultant increased water content of muscle mass.
Muscles and groups of muscles are enveloped in tough sheets of fibrous tissues called fascia. Fasciae create compartments of muscle groups that also enclose blood vessels and nerves. Bleeding, swelling and fluid accumulation in a compartment creates a dangerously high pressure within the compartment, interrupting blood flow to tissues and causing severe tissue damage. In abdominal compartments, these effects can lead to serious organ damage, notes WebMD.
Less serious side effects associated with C4 Extreme include headache, vomiting, nausea, tunnel vision and tingling of the skin, as listed by HealthResearchFunding.org.