Currently the U.S. Food and Drug Administration does not stand by the safety of tanning pills, and does not approve the use of canthaxanthin in tanning pills or in any cosmetic product. It does, however, give the thumbs-up to human consumption in small amounts as a color additive in many of the foods we eat. The FDA sets regulations that need to be followed when using canthaxanthin as a color additive -- the dos and don'ts specific to the pigment. For example, color additive regulations allow for canthaxanthin to be used in ketchup but not to color the skin.
Tanning-level doses of the pigment are much greater than the amounts we consume in condiments and processed foods -- amounts needed for a faux glow may be as much as five times more than we'd consume if we just relied on our diet. High doses of canthaxanthin may cause the palms of your hands and the soles of your feet to turn orange -- although it's temporary (it takes about two weeks for canthaxanthin to work its way out of your system), it's not quite the back-from-the-islands look you were probably looking for. Canthaxanthin can also cause gastrointestinal upset, dry or itchy skin and hives. And in some people those high doses of the pigment may cause damage to the eyes (the pigment causes crystals to form in the retina, causing a condition known as canthaxanthin retinopathy), as well as more permanent liver damage and aplastic anemia (a blood disorder) [source: Drugs, Mayo Clinic].