- André Biernath – @andre_biernath
- From BBC News Brazil to London

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Hyaluronic acid injections help fill in layers of skin that thin over the years
Over the past few decades, the search for a face free of wrinkles and other signs of aging has made a strong ally: hyaluronic acid, a substance that can be applied to the inner layers of the skin to promote hydration, filling and giving the desired contours in the skin, chin, cheeks, lips and eyelids.
One of the stars of the popular “facial harmonization”, the ingredient has become synonymous with beauty products and appears today on the labels of many creams and in advertisements for aesthetic clinics and practices.
But can it be used by everyone? Are there any contraindications and side effects? And what is the difference between creams sold in stores and injections administered in the office?
Understand the main issues related to this product in five points.
What is hyaluronic acid?
Hyaluronic acid is a substance made by our own bodies and those of many other animals.
It has the function of maintaining the natural hydration of the cells that make up the inner layers of the skin, as well as helping to support and fill this tissue.
“As the years go by and the aging process, we lose the extracellular matrix of the skin, which becomes thinner and looser,” says doctor Alessandra Grassi Salles, coordinator of the aesthetic, cosmetic and laser surgery group in the Department of Medicine. from the University of Sao. Paolo (USP).
This “extracellular matrix” of which the specialist speaks corresponds precisely to all the substances which “fill” the skin and hold the skin cells together.
As the years pass and these compounds naturally decrease, it is normal for the surface layer of our body to become flabby, wrinkle and eventually thin.
This is where hyaluronic acid applications come in: the objective is to replace or increase the amount of this substance, in order to maintain the skin with the desired thickness.
What is the difference between creams and injections?
“The big question is that the hyaluronic acid that we produce naturally has a very short half-life. It is absorbed by the body in less than 48 hours,” says Dr. Daniel Boro, from the Brazilian Society of Plastic Surgery.
“The industry then developed versions of this substance that are much stronger and stay in the body for months.”
Currently, the hyaluronic acid injected in aesthetic procedures is obtained by a process of fermentation of certain microorganisms.
Creams contain synthetic versions of this ingredient.
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During the aging process, the skin loses a set of substances that provide support and firmness to the superficial layer.
In addition to manufacturing, the two types of products bring fundamental differences in the mechanism of action.
“The basic function of the cream is to promote very superficial hydration of the skin. The role of injectables is to fill, support and rejuvenate the parts of the face”, summarizes Doctor Alessandra Ribeiro Romiti, adviser to the Department of Cosmetics Dermatology of the Brazilian Society of Dermatology.
Experts explain that the cream brings large molecules, which cannot go beyond the first layers of the skin. As a result, there is no possibility for the hyaluronic acid that is part of the formulation to go deeper and fill in the previously mentioned extracellular matrix.
A similar moisturizing effect, by the way, is observed in capsules that also provide this ingredient.
However, before you start using any of these, it is best to seek advice from an expert.
“If the person has oily skin and uses too much cream, there is a risk that this habit will clog the pores of the skin and cause acne,” says Salles.
Who is hyaluronic acid suitable for?
In general, there is no “cake recipe”, nor a general recommendation that suits everyone.
“We can apply hyaluronic acid as part of the process of managing skin aging,” says Boro.
According to Romiti, everything will depend on what the patient is looking for and their individual characteristics.
“There is no age to start treatment. There are people who start working on dark circles at 25, others seek to correct certain aspects of the face after bariatric surgery or want a more overall when they hit their 50s or 60s,” he says. .
Salles adds that in addition to the possibilities of modifying certain aspects of the face with new aesthetic technologies such as hyaluronic acid, the health professional must understand the motivations of each person.
“It’s a big mistake to think that you have to have a 30-year-old face to be happy. If you don’t work on what’s going on inside the patient, he may even have a younger face, but he never will.” really satisfied,” he says. .
Are the application results final?
Not. The hyaluronic acid used in the procedures lasts even longer, but it is gradually absorbed by the body. “It all depends on the type of gel and the part of the face it will be applied to,” Boro replies.
“In general terms, it stays in the layers of the skin for about a year, but that time usually varies between six and 18 months.”
It should be explained here that not all hyaluronic acids are the same: there are more consistent formulations and others that are more malleable.
The professional selects the appropriate type depending on the part of the face and the desired effect – on the chin or jawline, for example, a firmer gel may be necessary, while on the lips or eyelids it is preferable to apply a flexible product. and elastic, which will allow a more natural movement of the mouth or eyes.
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Hyaluronic acid creams even help moisturize the skin, but don’t reach the deeper layers
In addition to consistency, another factor that interferes with the duration of hyaluronic acid is the movement of facial structures. It tends to fade quickly in areas that move a lot, like the lips and eyes, and stay longer in less moving parts, like the jawline.
But of course, experts don’t wait until hyaluronic acid is completely depleted to indicate new applications.
“We do periodic monitoring and we have protocols for making replacements, as needed,” says Boro.
Is there a risk of side effects after the procedure?
Adverse events can occur and it is important that specialists and patients know how to identify them in order to act quickly and contain the damage.
One of the most feared dangers occurs when the product is injected into the wrong part of the face. With this, hyaluronic acid can stop inside the blood vessels that supply the face, where it will cause clogging that will lead to tissue death in parts of the nose, lips or even blindness.
“To minimize this risk, it’s important to do this procedure with professionals who have a lot of experience and years of training,” says Salles.
“It’s not something you learn in weekend class. It takes years of study to understand all the anatomical variations of the face and where the veins and arteries are likely to be. And even the most experienced specialists can make mistakes and unintentionally inject the substance inside a container.”
To minimize the damage, it is possible to use an enzyme called hyaluronidase, which has the function of absorbing poorly applied hyaluronic acid.
But this “antidote” cannot be used in all situations either: some patients are allergic to hyaluronidase and develop severe reactions.
Besides clogging of arteries and veins, other possible side effects are inflammatory reactions, marked by redness and swelling, and the formation of nodules at the injection site.
The good news is that because the product is absorbed by the body, these issues are usually temporary.
Finally, Salles considers that the excessive application of hyaluronic acid – and the undesirable aesthetic results of it – can also be considered an adverse event in certain situations.
“There are cases where 10 to 20 milliliters of hyaluronic acid are injected and we see impressive transformations,” he observes.
“But it can affect the movement of the face and the person no longer has the smile or the natural expression. You have to find a balance so that the person feels good and can recognize their own face in the mirror.”
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