Anatabloc does not have reported side effects because, as of 2014, it is a new product, according to Consumer Health Digest. However, the supplement contains vitamin A and vitamin D3, which cause side effects such as fatigue in high doses, notes WebMD.
Vitamin A is safe in low doses, but higher amounts of it increase the risk of hip fracture and osteoporosis, explains WebMD. People who consume large amounts of the vitamin over a long period of time experience mental changes, anorexia, nausea and fatigue, among other side effects. Large amounts of vitamin A can cause birth defects in some instances, so pregnant and breast-feeding women should ingest amounts of less than 10,000 units per day. Patients who abuse alcohol, have type V hyperlipoproteinemia or have liver disease experience side effects from taking vitamin A that can include vitamin A poisoning.
Side effects of vitamin D3 are rare and include changes to heart rhythm, trouble breathing, severe dizziness and allergic reactions, reports EverydayHealth. Vitamin D3 also causes dry mouth, vomiting, fatigue, headache and weakness, in rare cases. Those who take orlistat or bile sequestrants should consult a doctor before taking vitamin D3. Because doctors are unsure as to whether the vitamin causes harm to an unborn baby, pregnant women should also talk to their doctors before taking it.