Thinning lips, honestly.

Age perception uses colour as well as shape. In a large sample of Caucasian women the redness contrast between the lips and the surrounding skin fell with age, tracked the ages raters assigned, and could be moved: the same faces were judged younger when the contrast was artificially increased and older when it was decreased (facial contrast study). Repeated with Chinese, Latin American and black South African faces and French and Chinese raters, the same aspects of contrast fell with age and the same manipulation shifted perceived age (cross-cultural study). Makeup itself was then tested: 40- and especially 50-year-old women were judged significantly younger with makeup than without across three studies, while 30-year-olds looked no different and 20-year-olds looked older (makeup and perceived age). Moderate: perceptual experiments rather than clinical trials, but controlled, replicated and directly about the thing this guide is for. A colour a shade redder than the natural lip and a liner drawn on the border, not outside it, restore the two cues that age removed; drawing outside the border is the paint version of migration.

The histology of the ageing upper lip shows a thinning dermis with degenerating elastic and collagen fibres over a thickened subcutis (perioral ageing review), and the vermilion border is a fold of that dermis. Tretinoin thickens it: the meta-analysis of eight randomised trials in 1,361 patients finds fewer fine and coarse wrinkles (retinoid meta-analysis), and daily sunscreen use slowed visible skin ageing by 24% against discretionary use over four and a half years in 903 adults (sunscreen trial). Neither restores volume or length, and the retinoid goes on the skin above the border, not the red lip, which it will peel. Moderate for definition — the trials measured wrinkles, not borders — and the lip-lines guide grades the same two products for the lines that run into the edge.

Topical hyaluronic acid cannot reach the muscle where the volume went; it can hydrate the red lip, which is thin, gland-poor mucosa that dries easily, and a hydrated lip is slightly plumper and reflects more light. The studies say exactly that. Thirty-six women aged 22–40 applied a two-step hyaluronic lip treatment at least three times a day for four weeks, open-label, and improved on every graded parameter — texture, colour, definition, scaling, lines, plumpness — with corneometer hydration and caliper-measured plumpness up at weeks 2 and 4 (two-step lip study). A peptide-hyaluronic serum with a vesicle delivery system was tested in filler-naive lips and, double-blind against placebo, in lips augmented three to nine months earlier, improving shine, texture and the vermilion border with 94% rated improved in the first study (peptide-hyaluronic study). Emerging: manufacturer studies, young subjects, and endpoints a caliper can see and a dinner companion cannot. A useful thing to do to the surface; not a treatment for a thin lip.

The mechanism of every plumping gloss is irritation: a counter-irritant — capsaicin, menthol, cinnamon, niacin — dilates the vessels of the red lip and the lip swells for an hour or two, which the label calls plumping and a dermatologist calls contact irritation. Suction devices do the same with negative pressure and add bruising and, in the enthusiastic, broken capillaries. Lip and "face yoga" exercises train the orbicularis oris, which is not what ages — the muscle keeps working while the skin over it lengthens and the lip rolls in. None of the three has a trial of any kind; the comparison is the sixteen randomised trials of the gel (2026 meta-analysis) and the seven prospective studies of the toxin flip (lip-flip review), which are the two non-surgical treatments that do something measurable. Limited; harmless in moderation; a weekly gloss is a pleasure, not a plan.

Cross-linked hyaluronic gel placed along the vermilion border and into the body of the lip is the most-trialled aesthetic injection there is. The 2026 meta-analysis of sixteen randomised trials found lip fullness improved in 60% (95% CI 44–76%), aesthetic appearance in 82%, satisfaction in 68%, an adverse event in 50% — swelling 78%, firmness 48%, bruising 34%, tenderness 33% — and a serious adverse event needing treatment, follow-up or lasting beyond 30 days in 1.1% (2026 meta-analysis); an earlier pooled analysis put responders at 91% two months after injection (2021 meta-analysis). The pivotal trials underneath agree. In 225 adults randomised to Volbella or Restylane-L, 80.3% and 70.8% had improved a grade on the Lip Fullness Scale at three months, responders stayed above 60% through a year, perioral lines improved in two-thirds, and 96% reported satisfaction with their lips (Volbella trial); against no treatment, 84.7% of Chinese adults responded at three months versus 0% of controls (Chinese Volbella trial). In 270 adults randomised 2:1 to Kysse or Volbella, 88% had responded at week 8 and 60% at week 48 on a mean 1.82 mL in the lips, with an injection-site lump in 10% and bruising in 8%, resolving in a median of two weeks, and no serious events (Kysse trial). Restylane's own pivotal study randomised 180 adults 3:1 against no treatment and reported 90.1% responders at week 12 against 36.8% of untreated controls (Restylane label); Juvéderm Ultra XC's randomised 157 to treatment and 56 to delayed treatment, with 79% meaningfully improved at three months and 78% satisfied at a year (FDA summary); a newer soft gel, RHA3, was non-inferior to a comparator in 202 patients with a "natural look and feel" maintained through 52 weeks (RHA3 trial). Open studies in older patients — 73 people averaging 54 followed 18 months, 30 followed six with 67% still responding — fill in the age this page is about (18-month study; six-month study).

Strong, and every trial is the manufacturer's, with the untreated or the rival gel as control. The honest reading of the numbers: about 60% of trial lips are visibly fuller at a year, half swell or firm for a fortnight, one in ninety has a problem that needs a doctor, and the volumes that produced those results were 1.8–2.6 mL across lips and perioral lines in one or two sittings — not the single 1 mL "lip refresh" repeated every four months that accumulates into the overfilled type. The filler guide covers the gels, the injector and the dissolving.

The ridge at the edge of the red lip is what draws the bow and stops lipstick, and a fine gel threaded along it restores the ridge without inflating the lip. The products are the same ones as the row above, at a third of the volume: the Volbella and Kysse trials measured fullness and perioral lines rather than edge definition, but two-thirds of Volbella patients improved their perioral lines at three months and a year (Volbella trial) and Kysse is labelled for the lines as well as the lips (Kysse trial). Technique decides the result: in 216 women randomised by needle direction, where the gel spread followed where the needle travelled, and satisfaction was highest with the technique that kept gel from drifting upward (technique study), and the ultrasound study links vertical, deep techniques to migration (ultrasound study). Moderate: the products are trialled, the border use is series and technique. The lipstick stops feathering the same week; the lip does not look bigger, which for this type is the point.

A few units of toxin placed superficially along the upper vermilion border relax the marginal fibres of the orbicularis oris, and the lip everts a little, showing more red. The first prospective study with instruments gave 17 women 4 units of onabotulinumtoxinA and measured them by stereophotogrammetry: upper-lip height rose modestly but significantly at 15 days, volume did not change, perioral appraisal improved and satisfaction was high, and every adverse event — numbness, a functional limitation of the lip — was mild and gone within 30 days (17-woman study). A 2025 systematic review found seven studies with doses and sites, typically 4–6 units, consistent eversion and improved contour, and transient trouble whistling or drinking through a straw (lip-flip review); a 2026 series of three patients on 1 unit per site reports the same at two weeks with the authors' own warning about sample size (2026 series). Emerging: small, uncontrolled, short. It is a good experiment for the person unsure whether eversion is what they want, and a poor substitute for either the gel or the lift; too many units and the lip cannot hold soup.

Fat harvested from the abdomen or thigh and injected into the lips is sold as the permanent, natural alternative to gel, and the lip is the worst place in the face to keep a fat graft alive. Retention across 27 studies of facial fat grafting pooled to 47% and was lower in mobile areas than still ones (retention meta-analysis); at five years in 12 patients, the volume that remained tracked how much weight the patient had gained rather than how much was injected, and satisfaction had returned to pre-operative levels (five-year study). For the lips specifically, a retrospective series found higher satisfaction with a cell-enriched preparation than with sedimented or filtered fat (lip fat-grafting series). Emerging for the lip: no controlled trial, an operation, a second session often, and no hyaluronidase if the result is lumpy. Reasonable as part of a lift or a facelift when fat is being harvested anyway; not a first treatment. The volume-loss guide grades fat grafting where it works better.

The biostimulators that build collagen in a cheek do not belong in a lip. Calcium hydroxylapatite is contraindicated in hypermobile areas with thin skin such as the lips because of nodule formation (calcium hydroxylapatite chapter), and granulomatous foreign-body reactions after lip augmentation with it are reported (foreign-body reaction report); poly-L-lactic acid produced nodules in 4.7–28.6% of patients in the review of biostimulator inflammation, more than the other products (biostimulator review). Platelet-rich plasma injected into the lips has no trial of any size; the regenerative guide grades it for the face. Anything permanent — silicone oil, polymethylmethacrylate — injected into a lip is a lifelong problem when it goes wrong, and cannot be dissolved. Limited: the "natural" and "collagen-building" lip injections on a clinic menu are the two things a lip should not receive.