Dihydroxyacetone, more commonly known by its abbreviation of DHA is the main constituent component of fake tans, for mass market and professional salon use. If you’ve ever applied one of these products or been to a salon and had a spray tan in a booth, you may have noticed for some time afterwards that there is a distinct smell of burnt sugar or burnt biscuits on your skin. This is a sign that DHA has been used, and we’ll explain more about this as we go on.

DHA is used as a potentially safer alternative to sitting out in the sun, for consumers who want to achieve a healthy, bronzed glow all through the year and not just when they have been on vacation. A lot has already been covered in the press and within beauty journals about fake tanning as a tool for cosmetic enhancement. Not many people know anything about the main ingredient itself, how it was developed and its efficacy. Here, we aim to explain a little bit more about Dihydroxyacetone and tell you about its usage and safety.

DHA Molecule

What is Dihydroxyacetone?

Simply speaking it’s a chemical compound that causes the skin to turn brown when applied. It mimics the effect that natural exposure to the sun would have on the upper layers of the epidermis, without causing as much harm. DHA was first recognised as something that could affect the color of the skin as far back as the 1920s. It was used as part of the X-Raying process in medical establishments. Scientists noticed that if it came into contact with the skin, it caused it to turn brown.

However, it took another thirty years, before it was investigated any further. During the 1950s it was Eva Wittgenstein, working at the University of Cincinnati who carried out more intensive research into DHA. This time, it was being tested and analysed as an oral medication, on children who had diseases which meant they had problems storing glycogen. These children were given large doses of Dihydroxyacetone and were also made to apply it to their skin. Healthcare workers in charge of the study group noted that a short time after the children had used DHA on their skin, it turned brown.

Continuing her research, Wittgenstein began to use DHA on her own skin and found that she was able to perfectly replicate the darkening of the epidermis seen in the trials with the children. She also noted that the compound did not go any further down than the upper layer of the skin. The research was then carried on to experimenting with using DHA on patients who were suffering from the skin condition Vitiligo, which causes uneven skin discoloration, often incredibly upsetting for the patient suffering from it.

Why does DHA make the skin turn brown?

What happens when DHA comes into contact with the skin is that is reacts with your DNA and the amino acids and proteins present at the surface of the epidermis. According to your own personal genetic make-up and the amount of amino acids in your skin the DHA will react in different ways and produce different shades and degrees of darker tone to the skin. These can vary from yellows to browns.

The resulting transformations and differing skin pigments are known as melanoidins as they are similar in structure to the effect you would have if you sat out in the sun to get a ‘proper’ tan. However, the higher the concentration and the quality of the product can have a great effect on the final color the skin turns. If you’ve ever had a fake tan and it’s gone orange, that might be due to a high concentration of DHA in a poorly made product with lesser quality emollient ingredients in it.

How is Dihydroxyacetone formed?

Dihydroxyacetone is known as a simple carbohydrate that is more often than not derived from plant sources such as sugar beets and sugar cane and is formed from the fermentation of glycerin from these sources. At the time of writing it is still currently the only FDA approved sunless tanning ingredient. It is found in most self tanning products. In these formulations it will appear in concentrations ranging from 1% to 15%. Once applied to the skin it will take anywhere between two and four hours to develop on the surface of the skin and will continue to darken for anywhere up to three days after application.

Laying on Beach

How safe is DHA for use on the skin?

Earlier in the piece it was mentioned that DHA is a compound that can be used on the skin without causing too much harm, and indeed, in terms of contracting conditions such as melanoma, the use of DHA in fake tan is much safer than sitting out in the sun for hours on end. However, that does not mean DHA as an active ingredient is totally without problems, when applied to the skin. In fact, scientists who carried out an investigation for ABC News found that the ingredient does have “the potential to cause genetic alterations and DNA damage,”

Before anyone panics and throws their fake tan down the sink, there is lots of evidence to examine. Effectively the news reports are stating that DHA has the potential to cause genetic alterations, DNA damage, and cancer. But…can it?

A lot of research has shown that when applied, DHA doesn’t penetrate any further down that the upper level of the skin. This means that it won’t affect your internal organs, as you’re not breathing it in, or letting it sink into the lower base levels of the epidermis if you’re applying DHA self tan as a cream. It’s a slightly different story if it’s being used in a spray tanning booth and in fact the FDA has warnings about this type of tan, telling consumers to avoid these if at all possible as there is a chance you could inhale droplets of DHA, and further, it can actually find its way into the lower levels of the skin after all. At this stage, scientists are not sure how much can be inhaled, or how deep it can go into the skin – so they are simply advising consumers to avoid spray tans or only have them on special occasions, rather than making them a regular habit.

DHA was approved for use in self tanning products in the 1970s and many within the scientific world and those who work in the cosmetic industry believe that there isn’t any other chemical compound that is capable of producing such long lasting and satisfactory results.

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Maximum Safe Level of DHA in Self Tan Products

In the European Union, the Scientific Committee on Consumer Safety investigated the safety of using DHA in cosmetics back in 2010. From their research they determined that the use of DHA in skin care preparations would not pose any risk to the health of the consumer. Medical associations from across the world recognize DHA as a safe and skin friendly alternative to sitting out in the sun, or indeed, the risks posed by continued use of sun beds or UV tanning booths. Alarmingly, some medical researchers actually refer to the latter as ‘tanning coffins’.

Man Standing on Infinity PoolThere has been more recent research carried out into the possible risks of DHA in the use of tanning products and whilst there are no concerns over the risks of contracting skin cancer from continued exposure to UV rays from the sun, there are issues surrounding the reactions between DHA and the amino acids in the epidermis. It is believed that the two, in combination could potentially create more free radicals, which can attack the cell structures and degrade collagen and elastin fibers in the skin. In turn, this promotes premature skin aging and the earlier formation of wrinkles.

If consumers using self tan products then expose themselves to sunlight then the ageing process can be further accelerated, and much more pronounced than in someone who uses no products that contain DHA. This has a knock on effect on an individual’s DNA and can cause damage. In the USA, studies have shown that exposing fresh cells to DHA alters their microenvironment and can thus bring about the beginning of premature cell death. This is heightened if DHA happens to be inhaled (more commonly this occurs when self tan is used in tanning booths) or becomes absorbed into the mucous membranes or through skin that is broken.

So whilst consumers can be assured that using DHA in a self tan formulation is safe and if used instead of spending long periods of time in the sunshine, long term use can still lead to accelerated ageing and even more so if a lot of time is spent outdoors. The only way to protect yourself against ageing and sun damage is to use a broad spectrum SPF alongside any other skin care you choose to, and in conjunction with a self tan. SPF will not inhibit DHA from adhering to the skin.

DHA still continues to be approved as a self‐tanning ingredient, though it is apparent that there needs to be more research into any potential health issues it may cause, and also whether there are any better alternatives that could be discovered that pose less risks and avoid premature ageing of the skin.

How much DHA is contained in skin care products?

Skin care products that contain DHA usually do so at fairly high levels, in order to get maximum efficacy. Anything up to 15% can be used in conventional self tan formulas. This is why sometimes they can appear to give users unnaturally orange looking skin, and also why in some preparations consumers experience a burnt sugar or burnt biscuit smell when applied and left to develop.

Over the years scientists and manufacturers have discovered that in order to improve both these factors, the ingredients in the final formulation of product must be below pH5 when combined with DHA for maximum stability. Their concerns about free radical damage caused by DHA have been addressed by introducing powerful natural antioxidant ingredients into formulations and adding in erythrulose, another keto‐sugar occurring in red, to the formulation to counteract the potential orange glow that some users experience.

Ocean RipplesManufacturers are also tending towards the use of ‘purer’ DHA in powder form. Powder DHA is less likely to degrade over time when stored at 40 degrees celsius, whereas DHA in aqueous solution loses around 25% of its efficacy over time when stored at the same temperature.

Finding other new methods to encapsulate DHA in skincare without any detrimental effects have been relatively successful. Some brands are trying to add smaller concentrations daily moisturizers, which can be applied once or twice daily and have a gradual darkening effect over the course of a few days rather than developing all at once then fading. When the DHA is combined with emollients such as cetearyl glucoside the lipid structure of the skin gets strengthened and stops further moisture loss. Preparations that also contain Hyaluronic Acid aid moisturization and can also potentially help against the signs of ageing.

Some formulas now also contain DHA that is microencapsulated, to provide longer and slower release of the ingredient onto the skin. Additions of ‘naturals’ such as raspberry seed oil and aloe vera are also innovations which have proved to be successful in their aim to create a DHA based product that is more moisturizing and less likely to speed up the signs of ageing.

Over the last few years these innovations have worked to provide DHA products for tanning which not only make the color of your skin more ‘true’ and tans longer lasting, but also make products which are less likely to dry the skin or age it prematurely, in the absence of any other new ingredients to the market that will have the same effect and efficacy and are tested to the same high standards.

DHA remains the safer alternative to sitting out in the sun and contracting melanoma, but it hasn’t been without it’s own problems. Skin care companies and scientists have been working to ensure that they make DHA containing products as safe and well developed as possible.