Skin Rejuvenation

What is skin rejuvenation?

Skin rejuvenation is the name of a goal, not of a procedure. The goal is to improve the hydration, texture, elasticity and radiance of skin whose quality changes with age. There is more than one way to reach this goal. So saying ‘I’d like to have skin rejuvenation’ does not, on its own, amount to a plan; the first step is to look at what has changed in your skin.

Two processes work together in skin ageing. One is ageing linked to the passage of time itself. The other is photoageing, caused by the sun’s ultraviolet (UV) rays. Research shows that the two processes share common molecular pathways. The degree of photoageing depends largely on how much sun you have been exposed to and on your skin colour. The effect is more marked in people who spend a lot of time outdoors, live in a sunny climate or have fair skin.

Most of the skin is made up of collagen-rich connective tissue, which gives the skin structural support. In the dermis, the middle layer of the skin, collagen fibres decrease and break down with age; the skin becomes thinner and structurally weaker. The cells that produce and organise this collagen are called fibroblasts.

The face is not made of skin alone. Bone, ligaments, muscles, fat and skin are layers that lie on top of one another, and all of them change with age. However, when this change begins and how fast it happens differ from layer to layer and from person to person. Skin rejuvenation targets only the top layer: the skin itself. One of the approaches used for this is injections into the skin known as skin boosters. Studies describe these injections as being made up of different biological substances and as targeting dullness, loss of hydration and loss of elasticity.

RELATEDNon-surgical facial rejuvenation: what are the options?

SOURCEPMID 12437452PMID 25660807PMID 27248022PMID 39544509

What does ‘skin quality’ mean?

Skin quality is the main goal of skin rejuvenation, but it cannot be expressed with a single measure. According to the shared view of an advisory board of experienced dermatologists and aesthetic doctors from different countries, skin quality comes down to four categories that can be perceived in people of every ethnic background:

• Even tone: the skin’s colour looks even across its surface
• Surface smoothness: the skin’s surface is smooth; in everyday language, the skin’s texture
• Firmness: the skin is firm and taut
• Radiance: the skin looks fresh and glowing rather than dull

These four features can be affected not only by the surface but also by deeper tissues. That is why products applied to the skin (topical approaches) may not be enough on their own. Some studies add hydration and elasticity, measured with a device, to these categories. For example, in a randomised trial of 448 people, that is, a study in which participants were randomly assigned to groups, hydration and elasticity were measured with a device, while roughness and fine lines were assessed with rating scales.

When reading a result, you need to look at what was measured. In a review covering 903 studies that measured skin quality, 87% of observations were based on subjective assessments. Between 7 and 17 different definitions were used for each skin feature, and there was no common definition.

SOURCEPMID 34163203PMID 41971651PMID 41575202

When is it considered?

Skin rejuvenation is considered when the source of your concern is the skin itself. The problems addressed in studies reflect this picture:

• Dry skin and loss of hydration
• Dullness, that is, the skin losing its radiance
• Fine lines, surface roughness and visible pores
• Loss of elasticity
• Signs of sun-related ageing (photoageing) on the skin surface
• Age-related changes in skin quality on the neck, décolletage and backs of the hands

When a face looks tired in the mirror, the cause may be skin quality, but it may also be volume loss or sagging. Because all the layers of the face change with age, these can also occur together. Skin rejuvenation targets only the first of these; which one is most prominent in your case is determined at the consultation.

RELATEDVolume Loss or Sagging?

SOURCEPMID 42367716PMID 41971651PMID 37577796PMID 39544509PMID 25539986PMID 27248022

Skin Boosters

The name ‘skin booster’ means something that boosts, or strengthens, the skin. It refers to a group of injections given into the skin, which can be made of different substances. In Turkish they are called ‘gençlik aşısı’ (Turkish for ‘youth vaccine’), but they are not a vaccine and have nothing to do with the immune system. One of the substances used in this group is hyaluronic acid, which also occurs naturally in the skin. For skin boosters, non-cross-linked forms (in which the molecules are not linked to one another) or lightly cross-linked forms are used.

Cross-linking changes how the gel behaves. In a laboratory study of 28 commercial hyaluronic acid gels, non-cross-linked products appeared more suitable for supporting the middle layer of the skin, and cross-linked fillers more suitable for deep, volumising injections.

In an analysis that pooled data from several studies (a meta-analysis), hydration and radiance improved significantly after hyaluronic acid injections. For elasticity and pigmentation measurements, however, no significant difference was found compared with control groups. It is also reported that the effect of non-cross-linked products is often short-lived. In other words, skin boosters target the skin’s hydration and surface quality, not the contours of the face.

RELATEDSkin Boosters

SOURCEPMID 39544509PMID 39807700PMID 42487104PMID 41437808

PRP

PRP stands for platelet-rich plasma. Your own blood is separated in a centrifuge (a device that spins blood to separate it into its components), and the part rich in platelets (tiny blood cells involved in clotting) is applied to the skin. Growth factors released by the platelets stimulate the formation of new blood vessels and the production of the tissue’s supporting structure (the matrix). The preparation method changes the composition of the final product; that is why PRP is not a single standard product.

In studies, the effect of PRP on skin ageing has been found to be modest. In an analysis that pooled nine randomised trials covering 358 patients, both patient satisfaction and objective assessment were better in the PRP group than in the control group; there was no significant difference between the two groups in how often side effects occurred. In a systematic review (a review that searches the studies on a topic according to set rules) that collected data from 480 patients, the improvement was generally modest, and the most convincing evidence was for the skin’s surface texture. How long the effect lasts is not known.

RELATEDPRP

SOURCEPMID 41226837PMID 41694325PMID 31628542

Mesotherapy

Mesotherapy means giving small amounts of substances that are compatible with the body into different layers of the skin, using fine needles. It is the name of a technique, not of a product. That is why the line between mesotherapy and skin boosters is not sharp: it is becoming increasingly common to give skin booster products into the middle layer of the skin using the mesotherapy technique.

The strength of the evidence depends on what is injected. In a study of six people in which a solution containing vitamins and plant extracts was given around the eyes, no significant change was seen either in the examination findings or in tissue samples (biopsies). A review that looked at mesotherapy for skin rejuvenation in general also states that evidence of its effectiveness is still lacking.

In mesotherapy with hyaluronic acid, it is important to place the substance in the right layer of the skin. According to studies, correct placement is decisive both for improving the result and for reducing side effects such as irregularities in the skin and the Tyndall effect (a bluish tint under the skin).

RELATEDMesotherapyFacial Mesotherapy

SOURCEPMID 36098653PMID 42367716PMID 22788806PMID 34516073

Collagen stimulators

Collagen stimulators (biostimulators) are substances that, once injected into the tissue, stimulate your body’s own collagen production. Unlike traditional hyaluronic acid fillers, they make use of the body’s own capacity for renewal; the focus shifts from giving instant volume to renewing the tissue biologically. The two main substances in this group are calcium hydroxylapatite (CaHA) and poly-L-lactic acid (PLLA). These substances activate fibroblasts (the cells that make collagen) and act mainly in the dermis and in the connective tissue under the skin. As well as on the face, they are used on the neck, décolletage and body; PLLA and highly diluted (hyperdiluted) CaHA can be used in many different areas.

The small particles of CaHA (microspheres) give the tissue immediate structural support and also act as a scaffold for new collagen formation. The effect that comes from collagen production, however, is not visible on the day of treatment; it starts later and develops over time. PLLA in particular requires a staged series of sessions for a cumulative improvement. So knowing in advance that the result will appear later is part of setting realistic expectations. The enzyme hyaluronidase breaks down hyaluronic acid molecules and is used to manage problems related to hyaluronic acid fillers; CaHA and PLLA, however, are different substances from hyaluronic acid.

RELATEDCollagen Stimulator TreatmentsCalcium Hydroxylapatite (CaHA)

SOURCEPMID 42297014PMID 41517528

Neck, décolletage and backs of the hands

In aesthetic medicine, interest has turned to the neck as well as the face; here the targets are neck lines, wrinkles and skin laxity (loose skin). In a randomised trial of 146 people that treated the outer corners of the eyes, the neck and the décolletage together, superficial wrinkles decreased significantly in all three areas in the group given three sessions of a hyaluronic acid-based solution, compared with the group that used cream only. Two points need attention when reading this result: the comparison group used only an anti-ageing moisturising cream, with no injections, and the study was funded by a commercial company.

In a randomised trial in women with moderate or severe wrinkles on the décolletage, all participants were treated with diluted CaHA (mixed with salt water); there was no untreated comparison group. At 16 weeks after the last treatment, an improvement of at least one step on a wrinkle scale was reported in 73.5% of participants. A review of 24 studies on fillers and collagen stimulators in the neck reported that all three groups of substances improved neck wrinkles and skin laxity; however, the review found that the measures used varied, participant numbers were small and long-term evidence was limited.

The backs of the hands are another area where injections aimed at skin quality have been studied. In a small study of 22 women with moderate photoageing, one hand was injected with hyaluronic acid and the other, for comparison, with saline (salt water). In the women who responded, the density of the dermis measured by ultrasound increased more in the hand given hyaluronic acid.

Regular use of sunscreen can also slow skin ageing. In a randomised trial of 903 adults, after four and a half years, people who used sunscreen every day showed 24% less skin ageing than those who used it at their own discretion.

RELATEDNeck & Décolletage RejuvenationHand Rejuvenation

SOURCEPMID 42377479PMID 37577796PMID 38954627PMID 25539986PMID 23732711

Where does the evidence stand?

In skin rejuvenation, the strength of the evidence depends on the method and on the feature being measured. With hyaluronic acid injections, the most consistent finding is an increase in hydration. A systematic review of 13 studies on facial skin quality reported improvements in hydration, firmness, radiance and elasticity; even so, the evidence was rated only as ‘promising’, and the need for large randomised trials was emphasised. In the meta-analysis that pooled data from studies, however, the change in elasticity was no different from that in control groups.

Larger randomised trials have also been published in recent years. In the 448-person trial, hydration and elasticity increased more in the treated group than in the untreated group. In the 456-person trial, the treated group also showed a significant improvement in hydration and elasticity, and this improvement lasted for up to three months after treatment. However, in both trials the control group received no injection during the comparison period; in other words, the results were not compared with an injection containing no active substance (a placebo). Follow-up periods are also limited to a few months.

With PRP, the picture is less clear. In a study that assessed 13 systematic reviews of PRP for facial rejuvenation together, 18 of the 28 original studies on which these reviews were based had no control group. Confidence in 12 of the reviews was rated low or critically low, and the evidence was judged insufficient to reach a firm conclusion.

In mesotherapy, the evidence depends on what is injected. The 456-person trial, in which a hyaluronic acid-based solution was given using the mesotherapy technique, reported an improvement. A review that looked at mesotherapy for skin rejuvenation in general, however, states that evidence of its effectiveness is still lacking.

This does not mean the treatments do not work. It shows that current data are not enough to expect a particular result with certainty.

RELATEDMesotherapy and PRP: What Is the Difference?

SOURCEPMID 37038447PMID 39807700PMID 41971651PMID 42367716PMID 38557322PMID 34516073

Limits of this treatment

Skin rejuvenation treatments are aimed at the quality of the skin. This definition also sets out what they cannot do:

• They do not lift sagging tissue: they do not move tissue that has shifted downwards back up; that is the role of lifting methods.
• They do not correct volume loss the way fillers do: according to laboratory findings, non-cross-linked products appear more suitable for supporting the skin, and cross-linked fillers more suitable for deep, volumising injections.
• They do not remove excess skin and are not a substitute for a surgical facelift.
• Hyaluronic acid injections have not been shown to have an effect on pigmentation: after these injections, no significant difference in pigmentation measurements was found compared with control groups.
• The effect lasts for a limited or uncertain time: the effect of non-cross-linked products is often short-lived; with PRP, it is not known how long the effect lasts.

A feature you see on the surface of the skin may originate in deeper tissues. In the face, bone, ligaments, muscles and fat also change with age. If the source of your concern lies in these deeper layers, a treatment aimed only at the skin may not be enough; a plan that targets more than one layer may be needed.

Another limit has to do with measurement. Because there are no shared definitions for the features of skin quality, it is difficult to compare the results of different methods with one another. Knowing these limits is not meant to put you off; it is meant to help you set realistic expectations.

RELATEDWhy does the face sag?What causes pigmentation (dark patches) on the skin?

SOURCEPMID 41437808PMID 39807700PMID 42487104PMID 31628542PMID 34163203PMID 27248022PMID 41575202

How many sessions will I need, and when does the effect appear?

In skin rejuvenation, the number of sessions depends on the method; there is no single number for all of these treatments. At this clinic, these treatments are usually planned as 1–3 sessions; the number of sessions and the treatment protocol can be planned differently depending on the treatment. One procedure takes about 20–45 minutes. A topical anaesthetic (numbing cream) is used if needed. The timing of the follow-up is set according to the treatment and the session protocol. How long the effect lasts also depends on the treatment and on individual factors.

The protocols in studies also consist of a series of sessions, not a single treatment. In two large randomised trials, hyaluronic acid was given three times, once a month. In studies of mesotherapy with hyaluronic acid, between 1 and 6 sessions were given with non-cross-linked products; these studies reported that a maintenance treatment every few months was needed to keep the result. These numbers describe the methods of the studies; they do not show what your plan will be.

When the effect becomes visible also depends on the method. In the 448-person trial, hydration increased gradually as the sessions went on. With collagen stimulators, the effect develops over time because it depends on collagen production.

The following is recommended after the procedure:

• For the first 24 hours, do not apply heavy make-up or irritating products to the skin.
• Avoid strenuous exercise, saunas, steam rooms or hammams, extreme heat and massaging the treated area.
• For treatments such as PRP and skin boosters, aftercare advice may be adjusted separately depending on the method used.

RELATEDWhat to Expect After a Treatment

SOURCEPMID 41971651PMID 42367716PMID 36098653PMID 42297014

Known risks

Skin rejuvenation treatments are medical procedures and carry risks. With injectable treatments, the most common effects are discomfort, bruising, swelling (oedema) and redness; these are usually temporary and go away on their own. In the 456-person randomised trial, the adverse event rate was 1.67%, and all adverse events were mild or moderate. In the 146-person trial, most adverse effects were also mild and resolved within 48 hours.

Other risks have also been reported:

• Infection: in reports on PRP from different fields of medicine, the most common adverse event is infection after the procedure; PRP cannot be sterilised the way medicines are. In a review covering 423 patients, non-tuberculous mycobacterial (NTM) infections that developed after mesotherapy (NTM are a group of bacteria) were linked to injections contaminated with germs from the environment; recovery often took weeks, and in some cases scars remained.
• Nodules (small, firm lumps under the skin that you can feel): these occur mainly with collagen stimulators. In 5,081 CaHA treatments, the adverse event rate was 3%, and 96% of these events were reported as nodules; most are not visible and go away without any intervention. With PLLA, nodules usually appear a few weeks after the injection.
• Vision loss: reports linked to PRP also include blindness. Most reports of adverse events linked to PRP are case reports (publications describing individual patients), so a cause-and-effect link between PRP and each adverse event has not yet been established.

At this clinic, these treatments are not carried out in the following situations:

• Pregnancy
• Active infection or inflammation in the treatment area

The following need a doctor’s assessment:

• Bleeding or clotting disorders
• Significant chronic illnesses or immune system disorders
• The medicines you take
• A history of allergies

Suitability is also assessed separately for the method to be used. Do not stop taking your prescription-only medicines on your own.

Contact the clinic if pain, redness or swelling is more severe or lasts longer than expected, or if anything else develops that worries you. In sudden, serious situations such as a severe allergic reaction or difficulty breathing, call the emergency number 112.

SOURCEPMID 24719076PMID 42367716PMID 37577796PMID 39100535PMID 39916988PMID 28247924