Truths and myths about cosmetic products: Aloe Vera, Rosa Mosqueta, dyes and parabens

Cosmetics, in general, is the perfect breeding ground in terms of the origin of various myths and hoaxes. After all, we are talking about products that we almost always apply directly to our skin, which can cause us to treat them with excessive respect (and even more so if you continually receive alerts and warnings without rhyme or reason). .

No, aloe vera is not the most appropriate treatment for burns or wounds

Surely, among the various uses attributed to aloe vera, you have ever heard that it is recommended to treat burns or wounds, either directly using the gel from the plant or as part of a cosmetic product. The truth is that no: aloe vera has certain irritating components that can cause side effects when applied to skin conditions.

"Aloe vera is not a good treatment for burns, wounds or, in general, for dermatitis. In the event that the skin is altered or presents some type of aggression, there is a greater risk of sensitization, that is, , to develop immunity so that, if the aloe vera comes into contact with the skin again, it could generate an inflammatory reaction," Sara Gómez Armayones, a dermatologist at the Hospital Clinic in Barcelona, ​​confirms to Maldita Ciencia. "In fact, we see patients with allergies to aloe vera. There are products that are much better suited to treat this type of lesions," she adds.

In Maldita Ciencia we already talked about how to deal with a burn or a wound or cut in this article on first aid. Also, if you want to learn more about the dermatological use of aloe vera, you can take a look at this article.

What do we know about dyeing your hair during pregnancy? Although it is safe for the baby, more studies are needed, so experts recommend prudent use

It is true that there are studies that suggest a possible negative relationship between these products and the health of the baby, such as alterations in their birth weight or an increased risk of leukemia during the first two years of life. However, the research that is currently available has been done on mice, using a much larger amount of product than is used to color hair and continuously, not like color treatments of this type that use a women. In addition, the proportion of the product that reaches the skin is very small (and the amount that manages to be absorbed is even less), so if part of it reached the placenta, the amount would be minimal.

Taking all these variables into account, can we conclude that dyeing during pregnancy or the months leading up to it could be harmful to the unborn baby? The answer is given by Rita Vassena, scientific director of Eugin, to Maldita Ciencia: “In principle, no. There are no substantial studies that show that using these products could be detrimental to the fertility of the mother or the health of her child.

The fear that these stains could be harmful stems from observations or research going back decades. These suggest that, by supplying some of their compounds in high concentrations to rats and mice, they could alter their fertility. “But the doses used in these studies are much higher than those found in hair products,” Vassena clarifies.

Even so, "the position of the doctors is to recommend a prudent use: continue using the products without fear, since their toxicity is far from proven, but minimizing the possibility of absorption, just in case", explains Vassena. Here we talk about these and other studies in relation to the subject.

What we know about dyeing your hair and the risk of cancer

You asked us and the answer is not simply "yes" or "no". Go for it.

The National Cancer Institute in the United States explains that hair dyes that were marketed in the 1970s, when dyeing became widespread, contained some chemicals, such as aromatic amines, which were classified as carcinogenic to animals. and as possible carcinogens for humans, especially in cases of bladder cancer and lymphoma among others. Since the mid to late 1970s, manufacturers of these dyes have been substituting other ingredients for these dyes, and there is no evidence to ensure that these new ingredients also increase the risk of cancer.

Research in this regard continues to develop and so far the results are contradictory: some have found a relationship between the personal use of hair dyes and the risk of leukemia, lymphoma, breast cancer, bladder cancer and other cancers, and others not. That is why the IARC, the international cancer research agency, has concluded that this personal use cannot be classified in terms of its carcinogenic action for humans.

What the IARC does consider to be a probable carcinogen is working in a hairdresser or barbershop, due to constant exposure to dyes and other similar products.

What we know about nail lamps and skin cancer: an increased risk is unlikely but it is advisable to put sunscreen on your hands before using them

Can UV lamps burn off? used in nail salons (to speed up the drying process of nail polish and harden gel nails) increase the risk of developing skin cancer or melanoma? It is true that UVA rays are a risk factor for this disease, however it is highly unlikely that this will occur using manicure devices, according to scientific evidence in this regard.

Studies show that the amount of radiation emitted by nail salon lamps is not powerful enough to pose a real risk even to those who regularly receive nail salon treatments. They also confirm that the possibility of it influencing the risk of developing skin cancer is very low.

Even so, and despite the few minutes that radiation exposure lasts, this study published in the Journal of the American Academy of Dermatology warns that, during drying, the hands receive energy equivalent to the recommended daily limit for of those people who work outdoors, who receive these rays (this time from the sun) continuously. This is why the authors recommend applying sunscreen to the hands 30 minutes before receiving the treatment and avoiding washing them with soap and water before starting it, so as not to remove the skin protection. Here you can read more on the subject.

No, there is no evidence that some of the ingredients in Mercadona shampoos are carcinogenic

Once again, some of the doubts that you send us have to do with cosmetic products from Hacendado, Mercadona's private label . The origin is a Facebook post that specifically points out two ingredients, in this case from shampoos: sodium lauryl sulfate (SLS) and sodium lauryl ether sulfate (SLES). In that post it is suggested that they can cause cancer when mixed with other ingredients, as well as being highly irritating and toxic. These are ideas that have been circulating on the internet for a long time (Snopes already denied it in 1999) and in those statements without evidence and others that are highly distorted.

Both substances are used for their surfactant action, that is, they trap oily compounds from hair and skin and help to remove them with rinsing. They are necessary to form the foam of soaps and shampoos. It is the first of the two, the SLS, which causes more concern.

For starters, there's no evidence that SLS or SLES causes cancer. There are no studies that confirm it and no national or international security agency classifies these substances as carcinogenic. This is the case of the International Agency for Research on Cancer (IARC), belonging to the WHO; the US National Toxicology Program, the US Environmental Protection Agency or the European Union. Bottom line: there is no evidence or research linking the use of these two ingredients to cancer.

But it is true that SLS can be irritating in very high concentrations or if it remains on the skin for too long. For this reason, it is mainly used in products that do not spend too much time in contact with the skin, such as soaps or shampoos, and the concentration does not normally exceed 15%. In the case of longer application products, such as creams, the concentrations of this substance should be even lower (around 1%). In any case, it can be a powerful eye irritant and therefore it is best to avoid contact with the eyes. If you still have doubts, you can clarify them here.

What are parabens and why you shouldn't worry about them being in your shower gel

As we explained in Maldita Ciencia, parabens are a group of substances that are used as preservatives in cosmetic products and of personal hygiene. It is used to prevent fungi and bacteria from proliferating in items such as deodorants, shower gels and body creams. Their use worries sectors of society and that is why some brands have chosen to eliminate them (for example, Eroski in 2013). Is there really something wrong with parabens?

The main concern regarding the use of parabens in cosmetics is that they may have an effect similar to that of estrogen, the female sex hormone, causing a hormonal imbalance in our body. This could potentially cause different pathologies, such as breast cancer.

One of the most common arguments is a study published in 2004 that found traces of parabens in breast tumors. However, the study did not conclude, nor has any other study since, that parabens had been the cause of the tumors.

Several health authorities have searched for this possible effect, without finding it. According to the American Cancer Association, there are no studies linking parabens to any health problem, including breast cancer, and for the European Scientific Committee on Consumer Safety, research in this regard is inconclusive.

What paraffin is used for in cosmetics and why it is not toxic or dangerous and does not imply "smearing" with oil

You have asked us about this Facebook post that exposes the supposed negative effects and properties of paraffin, one of the most common components in cosmetic products in our usual supermarket. The first thing is to clarify that liquid paraffin (paraffinum liquidum) is used in cosmetics and not dry paraffin, and it is this substance that we are going to talk about in this article. It is a very common compound and can be found in the labeling of children's gels, colognes and body oils.

Despite the concerns it raises, it's important to be clear that liquid paraffin is safe in any amount. The legislation imposes a limit to the percentage of impurities that it can have (less than 0.005% or 3% of the total, depending on the substance) since these possible impurities can pose a health risk.

Where does the fear of a compound so widely used in the composition of these articles come from? Part of the concern arises from its provenance: paraffin is a mineral oil that is extracted from petroleum. But it must be clear that this does not determine its safety or toxicity. "Chemically, it doesn't matter what the origin of the compound is, that's not going to make it better or worse," Deborah García Bello, a chemist and science disseminator, explains to Maldita Ciencia.

In addition, it is inert and does not even cross the epidermis, the first layer of the skin. That is why there is no evidence that it is capable of causing allergies or irritations, much less other problems such as dizziness, headaches, coughing, dark spots or loss of concentration, as the Facebook post warns.

First date of publication of this article: 06/05/2020