Dihydroxyacetone (DHA) the main ingredient in self-tanning products has been in the news of late. Another caveat emptor (buyer beware) as to the unregulated cosmetic industry. In this day and age one must read each and every ingredient on a label or check with Environmental Working Group's cosmetic database to avoid putting poisons on yourselves or your children's bodies.
The FDA originally approved DHA for "external" use back in 1977, when it was first used in tanning lotions. Dihydroxyacetone (DHA), performs its bronzing by reacting with amino acids in the skin's surface. The FDA has in the past maintained that DHA does not get absorbed into the body. And scientists assumed that because DHA reacts so rapidly on the dead surface layers of the skin, minimal amounts went down further. But they were wrong. Non-absorption might be true of substances such as rubbing alcohol which evaporates rapidly and certain molecules too large to pass through the skin, but a percentage of many chemicals easily find their way into our deeper layers of skin and are then picked up by the body's bloodstream. Even though only a small percentage of what one puts on their skin ends up absorbed, the amount of product applied to the skin, which is our largest organ, is usually considerable.
Studies uncovered by ABC News showed that in 1999 the FDA was aware that 11 percent of the applied DHA (in lotion) made its way down into living skin cells, and they were also aware that .05 percent goes even deeper and is swept up into the bloodstream. Thinking this a minimal enough amount, the FDA discontinued testing and no further studies were done to check for toxicological impacts on human health. Problem enough, but now DHA artificial tanners are now being sprayed and air-brushed on. Airbrush application uses compressed air to disperse the product as a fine mist onto the skin. The issue with this, is that DHA is easily picked up by the mucous membranes, the eyes, the mouth, the lips and if breathed in, the lungs. Add to this, the 11 percent that makes it down into your living skin tissue, and you have significant exposure. The FDA has not approved DHA for spray usage. Also new are self-tanning pills, another unapproved use of DHA. As a matter of fact, the FDA advises that "DHA should not be inhaled or ingested."
ABC News has also recently uncovered from the FDA, through the Freedom of Information Act, that studies by scientists outside the FDA show that DHA has been shown to have a "mutagenic" effect on genes, and potentially promotes the development of cancers and malignancies. Studies have yet to be performed on human cells, but the tests on different types of cells and organisms, including bacteria, salmonella, ecoli and mice skin cells have shown mutagenic effects. What is creating a stir, is that the physicians who have reviewed these studies say DHA has the potential to create mutations or change DNA in living cells.
Note: The 'DHA' acronym is in use for both dihydroxyacetone and docosahexaenoic acid, the latter an omega 3 fatty acid. The latter DHA can be found in salmon and milk, it is approved by the FDA to be eaten and is thought to have positive effects on existing heart conditions, lupus, ADHD, rheumatoid arthritis, asthma, hypertension, atherosclerosis, depression, adult-onset diabetes mellitus, myocardial infarction, thrombosis, and some cancers.
abcnews.go.com - Are Spray on Tans Safe?