Skin boosters: what they do, how many sessions and risks

How many sessions you need, and how long it lasts

The usual plan is a course rather than a single treatment. An expert consensus recommended up to three initial sessions, followed by maintenance. It described a visible effect after the first session and a gradual improvement in texture for up to 12 months with repeat treatment every four to six months ^[6].

Protocols vary with the gel. A review of 34 studies found that non-cross-linked gels were given in one to six sessions, weekly to every two months, and lightly cross-linked gels in one to three sessions, four to 36 weeks apart ^[5]. The same review noted that keeping the result requires maintenance every few months.

In the largest randomised trial so far, 420 adults received either three full-face sessions three weeks apart or no treatment. Blinded evaluators saw an improvement in 91% of those treated, against 4% of the untreated group, and the effect held at six months ^[3].

What to expect, realistically

The evidence supports a real but modest change. A meta-analysis found that injected hyaluronic acid improved hydration and radiance compared with controls. It did not find a significant improvement in elasticity ^[2]. A systematic review of 13 studies reported improvements in hydration, firmness, brightness and texture, but concluded that larger randomised trials are still needed ^[1].

In a split-face trial, one side of the face was treated with a non-cross-linked gel and the other with saline. After three sessions, hydration rose by 35% and firmness by 27% on the treated side. Fine lines around the eyes became shallower, and the investigator saw an improvement in 82% of participants, with none on the saline side ^[4].

So, in practice:

• Skin that looks and feels more hydrated, with a softer glow.
• Fine lines that are softer, but not gone: in the large trial, about half of those treated (52%) had an improvement in fine lines at its peak ^[3].
• A gradual change over the course, not an overnight transformation.
• No change in the shape of your face, and no lift of sagging skin.

Many studies are small, short or funded by manufacturers. Results also depend on your skin: heavily sun-damaged skin usually needs other treatments as well ^[5].

Risks, and who it is not for

Most side effects are mild and settle on their own. Small raised bumps at the injection points are normal for a few hours or a day or two. Redness, tenderness, slight swelling and the odd bruise are common. In the large trial, adverse events were mild, short-lived and became less frequent with each session ^[3].

If the gel is placed too close to the surface, it can leave small irregularities or a faint bluish tinge, known as the Tyndall effect ^[5]. Precise technique and the right depth are what prevent it.

Delayed inflammatory reactions, such as firm or tender nodules, are rare. A 2026 meta-analysis of hyaluronic acid fillers for the face found about one per 2,000 patients per year of follow-up. The median onset was three months, but they can appear weeks or years later ^[7]. That analysis covered fillers in general, not only skin boosters.

Serious complications, such as a vascular event, are rare. Most adverse events can be avoided with careful planning, a good knowledge of anatomy and the right technique, and the doctor must be ready to treat them ^[8].

Skin boosters are not recommended in pregnancy or while breastfeeding, with an active infection, cold sore or acne flare in the area, or with an uncontrolled autoimmune condition. They are also not for anyone who has had a severe reaction to hyaluronic acid before. And they are not the answer if what bothers you is sagging or deep folds: for loss of firmness, read about collagen stimulators.

How to choose where to have it

Skin boosters can look like a quick, simple treatment, which is exactly why the setting matters. Check that the clinic is a licensed healthcare centre, that a registered doctor examines and treats you, that they tell you what type of gel they use and why, and that a follow-up is planned. We cover this in our guide on how to choose an aesthetic clinic in Spain.

Be cautious with packages sold without a consultation, or treatment outside a healthcare setting. If you split your year between the Costa del Sol and home, ask how sessions and maintenance will fit around your travel.

How we approach it at Rejuvelook

At our clinic in Fuengirola, any skin treatment starts with a medical consultation. The doctor examines your skin and the structure of your face, and explains what is causing the change you have noticed. If your skin would benefit, the doctor may propose a hydrating hyaluronic acid treatment, explain the plan and the number of sessions, and review the result. If another approach suits your skin better, or nothing is needed, we will tell you. We see patients in English or Spanish.