Polynucleotides: how many sessions?

• Under-eye area: commonly two to three sessions, sometimes four where the skin is very thin or depleted.
• Full face: commonly three sessions.
• Neck, décolletage or hands: commonly three sessions, occasionally more, as these areas tend to respond slowly.
• Scalp: where offered for hair-related concerns, longer courses are typical, and the evidence here is weaker still.

Manufacturers publish their own suggested protocols and these differ between brands, which is one reason quoted session numbers vary between clinics.

Two to four weeks is the usual interval. The reasoning is that the material is broken down over a few weeks, so repeating within that window is intended to maintain a continuous stimulus while the skin responds.

Sessions much closer together are not standard practice and offer no established advantage. If life gets in the way and a session slips by a week or two, that is rarely a problem; ask your practitioner rather than assuming the course is ruined.

Results are normally assessed about four to eight weeks after the final session, because change continues to develop after the injections stop. Judging the outcome the week after your last appointment is too early.

Clinics commonly suggest either a single top-up session every six months or a repeated short course annually. Some people choose to stop after one course and see how the skin behaves.

The effect is not permanent. Skin ageing continues regardless of treatment, so maintenance sustains a difference rather than compounding it indefinitely. The honest position is that long-term data on repeated courses over many years is limited.

When budgeting, work out the annual cost rather than the single-session price. See costs in the UK.

• Age and skin condition. Thinner, more sun-damaged or more depleted skin often takes more sessions before any change is noticeable.
• Area and product. Different brands and concentrations carry different manufacturer protocols.
• Response to the first sessions. A practitioner should reassess rather than simply completing a pre-paid package.
• Other treatments. Energy-based devices, peels, filler or botulinum toxin in the same area may affect timing.
• Health and lifestyle. Smoking, sun exposure and some medical conditions affect skin healing.

If you complete a full course and see no difference, it is reasonable to stop. Continuing indefinitely in the hope of a delayed response is not supported by evidence. Discuss alternatives, including other injectable options or non-injectable approaches.