Hyaluronic acid (HA) is a molecule naturally produced by the body and present in connective tissues for the purpose of moisturising and protecting them.
In addition to cartilage and joints, HA is a fundamental substance of the dermis and has a supporting function in the skin.
It is because of these characteristics that hyaluronic acid finds popular application in various fields:
- Cosmetics in moisturising and anti-ageing creams
- Orthopaedics for the treatment of arthrosis
- In the form of antioxidant food supplements
- Ophthalmic for the production of eye drops or ophthalmic ointments
In this article, we will focus on the use of hyaluronic acid in aesthetic medicine, specifically regarding the so-called HA fillers, which are increasingly used to correct major facial imperfections.
The question we will try to answer is: is hyaluronic acid safe?
To provide those wishing to undergo an HA filler treatment with all the information they need to make an informed decision, in this article we will look at the following topics:
What is hyaluronic acid?
Before discussing the contraindications and side effects of hyaluronic acid, it is good to explore for a moment what HA is.
As stated before, hyaluronic acid is a natural constituent of connective tissues including the dermis.
So this molecule, technically a high molecular weight polysaccharide (a sugar) from the glycosaminoglycan group, is already naturally present in the body and, when injected through fillers, is completely and naturally reabsorbable.
With the physiological ageing process, the amount of hyaluronic acid decreases drastically and this leads to a loss of hydration, firmness, volume and the appearance of deep wrinkles on the face.

What are the side effects of hyaluronic acid?
Specifically for its very nature and the fact that it is naturally present in the body, hyaluronic acid, per se, has no side effects and is generally well tolerated.
Thus, in the specific case of aesthetic medicine, any side effects are not to be found in the substance itself, but rather in the how it is administered and in the quality of the hyaluronic acid used.
In fact, there is certainty regarding the benefits of hyaluronic acid on the skin.
But it is essential to know that it is not sufficient to say “hyaluronic acid” because this is just a generic term behind which different production processes to obtain it and a different quality of raw material are hidden.
Therefore, to avoid side effects, it is essential to watch out for four specific conditions:
- Only consult doctors specialised in aesthetic medicine. Used as a filler to correct skin imperfections and more, hyaluronic acid, in the form of a transparent gelatin, is injected into the dermis using very fine needles.
Although it is a non-invasive and rather simple outpatient treatment, it is essential that it is performed by a qualified specialist who must know exactly where and how to use it.
The doctor must also be able to identify the right density hyaluronic acid for the specific area to treat.
On the contrary, an inexperienced doctor may cause severe post-injection trauma such as persistent redness, nodules, intermittent oedema (swelling that comes and goes), itching and even abscesses.
- Make sure of the type of hyaluronic acid in use for the treatment. In this respect, it is highly recommended to ask about the manufacturer and the production techniques used (e.g. to verify that the hyaluronic acid was obtained through a bacterial fermentation process).
While allergies or rejection problems are rare if not impossible due to hyaluronic acid per se, it is the agglutinating substances used to produce it that may cause them.
- Ensure that the surgeon uses a sealed ampoule and ask that they show you the label of the product used, certifying its quality and integrity.
- Report to the doctor the presence of previous fillers, even if they were done a long time ago and, above all, if they were permanent ones (non-resorbable). In these cases, the risk of side effects of hyaluronic acid is much higher.
Given all these conditions, any side effects of hyaluronic acid are minimal and include: small haematomas, bruising, oedemas, numbness and bruising in the area where the treatment was performed.
Therefore, mild symptoms tend to disappear spontaneously within a few days.
What are the contraindications of hyaluronic acid?
From what we have just said, it is clear that the contraindications and side effects of hyaluronic acid are very minimal if the product is properly used.
On the contrary, the effects and benefits of hyaluronic acid on the face and its ability to offer natural and long-lasting results make it increasingly the most widely used solution to correct a wide variety of imperfections including:
- Smoothing out wrinkles
- Plumping up thin lips without creating an unsightly effect.
- Correcting a nose with a hump without resorting to surgical rhinoplasty
- Redefine face volumes
- Moisturising the skin
- Correcting aesthetic eye problems such as sunken eyes

However, there are rare cases of contraindications to hyaluronic acid due to particular conditions or the patient’s general state of health. Let’s see what they are.
When not to get a filler treatment?
As mentioned, there are special situations when it is recommended not to undergo filler treatments, in particular:
- Pregnancy and breastfeeding
- Allergies to the excipients in the filler
- History of allergies
- Blood coagulation diseases that can lead to haemorrhagic episodes
- Auto-immune diseases (such as rheumatoid arthritis and Crohn’s disease)
- Skin diseases
- Heart disease
- Eczema and herpes
It is also essential to inform your doctor if you are taking any medications.
Finally, as the specialist will undoubtedly inform the patient, after undergoing a hyaluronic acid filler treatment it is absolutely necessary to avoid exposure to the sun and cold even if the effects mentioned above have not occurred.
However, in the latter case it will be necessary to wait until they have completely disappeared before getting sun exposure.
Is hyaluronic acid safe?
We have seen how – except in special cases for which there are specific contraindications to the use of hyaluronic acid or in the case of errors related to the doctor’s experience – hyaluronic acid is safe and well tolerated by the body.
As already mentioned, another element that makes the difference in terms of the side effects to hyaluronic acid is the quality of the product used and this, in turn, is closely related to the raw material and production processes used to obtain HA-based injections .
The entire Foliage by Phitogen product line for example, offers aesthetic medicine specialists complete support in the implementation of high-end and 100% Made in Italy hyaluronic acid filler lines.
The Hyaluronic Acid extraction process takes place in a certified production site where it is possible to obtain a raw material free of nucleic acids and residual proteins, guaranteeing excellent quality standards and maximum safety.
Foliage injectors by Phitogen are devices based on pure hyaluronic acid of non-animal origin, fermentatively produced by streptococcus equi.
The innovative and patented 2CORE Technology means that Foliage fillers require less chemical cross-linking agents (BDDE) and thus are particularly malleable, homogeneous and integrable with skin tissue.
The aim of the most innovative hyaluronic acid fillers is to preserve and improve the physiological wellbeing of the skin, without distorting the person’s original image, but allowing aesthetic time to be handled naturally, through the use of high-end bio-based revitalising products.
Thus, no longer a forced and plastic look, but a ‘cyclic maintenance of beauty’ approach.
In this manner, not only will the side effects of the old generation hyaluronic acid be avoided, but also those aesthetic accidents caused, for example, by excessive and artificial volumes.

How to use hyaluronic acid correctly?
As we have stated repeatedly, the number one rule for the correct and safe use of hyaluronic acid is to refer to doctors specialised in aesthetic medicine, while being wary of any other party offering to perform a filler treatment without the necessary qualifications.
Once this first and fundamental step has been taken, the next step is to ask for all the necessary clarifications on the type of treatment chosen by the doctor according to the imperfection to be corrected. This will ensure that it is the best quality hyaluronic acid.
However, the patient must provide the specialist with all relevant information on his/her state of health and any diseases or allergies. Only in this manner the doctor may carefully assess any contraindications to hyaluronic acid infiltrations in the specific case.
Foliage is the result of 20 years' experience of Phitogen Holding S.p.A. - a leading group in the production of hyaluronic acid-based injectables. Foliage distributes a complete range of high-performing intradermal products.
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