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Spilanthes acmella for Skin Rejuvenation

Evidence Review created on 09/28/2026 using AI4L / Opus 5.5

Also known as: Acmella oleracea, Spilanthes oleracea, Toothache Plant, Paracress, Jambu, Electric Daisy, Buzz Buttons, Szechuan Buttons, Gatuline Expression

Motivation

Spilanthes acmella (toothache plant, also sold as jambu or Acmella oleracea) is a small tropical flowering herb whose flower buds cause a strong tingling and numbing feeling on contact. Its main active compound, spilanthol, is thought to quiet the small facial muscles and nerve signals that deepen expression lines, which is why skin-care makers promote the extract as a plant-based alternative to wrinkle-relaxing injections.

The plant has a long history in South American and Asian folk medicine for toothache and mouth sores. Since the mid-2000s, a patented flower extract has been added to eye creams and serums, and small studies have measured wrinkles, skin moisture and firmness in volunteers applying these products. Much of this work was carried out or paid for by ingredient and skin-care companies.

This review examines the evidence on applying Spilanthes acmella to the skin for rejuvenation in health-focused adults: how it is thought to work, how strong the human data are, which risks apply, including plant allergy, and how it is used in practice.

Benefits - Risks - Protocol - Conclusion

This section lists in-depth reviews and primary research that discuss Spilanthes acmella and its skin-relevant activity.

Only four items are listed because no other source discussing Spilanthes acmella for skin in depth met the eligibility rules; available web content consisted mainly of brand blogs and trade-press news.

No relevant content was found from Rhonda Patrick, Peter Attia, Andrew Huberman, Chris Kresser, Life Extension Magazine or Lifespan.io; none of these platforms has published material on Spilanthes acmella or spilanthol.

Grokipedia

  • Toothache plant

    Covers botany, taxonomy (Acmella oleracea as synonym of Spilanthes acmella), spilanthol chemistry and traditional uses; useful background on naming, although skin-specific evidence is thin.

Examine

  • Toothache Plant

    Examine’s entry describes the herb as understudied, covering traditional and oral uses (toothache, aphrodisiac, testosterone); it does not evaluate topical skin rejuvenation.

ConsumerLab

No ConsumerLab article on Spilanthes acmella exists.

Systematic Reviews

This section lists the systematic reviews available on PubMed for Acmella species, none of which addresses skin outcomes.

No systematic review or meta-analysis covers either the claimed skin-rejuvenation effect or the principal skin risk (allergic contact dermatitis, an itchy allergic rash where a substance touches the skin); both sides of the trade-off are unrepresented.

Mechanism of Action

Spilanthol, an N-alkylamide (a fatty-acid-derived compound, related to the tingling agents of Sichuan pepper and echinacea), is the main active constituent of Spilanthes acmella flower extracts.

  • Muscle-relaxing (“Botox-like”) claim: In a nerve–muscle co-culture (human muscle cells innervated by rat embryonic nerve tissue), the extract blocked muscle contractions, with full recovery within 1 hour of washout, per the patent of its originator, Gattefossé (patent US7531193). Whether enough topical spilanthol reaches facial muscle is untested.
  • Sensory-nerve activation: Affinin (a synonym of spilanthol) activates TRPA1 and TRPV1 (heat- and irritant-sensing ion channels) and cannabinoid receptors, which may explain the tingling (Luz-Martínez et al., 2024).
  • Anti-inflammatory signalling: In keratinocytes (surface skin cells), spilanthol lowered COX-2 (an enzyme producing inflammatory messengers) and MAPK (a signalling chain driving inflammation) activity (Huang et al., 2018); in macrophages (immune cells), it blocked NF-κB (a master switch for inflammatory genes) (Bakondi et al., 2019).
  • Penetration enhancement: Spilanthol permeates excised human skin and increases uptake of co-applied drugs up to 4.6-fold and mold toxins up to 6.4-fold (Boonen et al., 2010; De Spiegeleer et al., 2013).
  • Competing explanation: Hydration and texture gains may stem from moisturizing bases rather than spilanthol.

Pharmacology: In rats, oral spilanthol is well absorbed with an elimination half-life of about 1.2 hours; in mice, injected spilanthol rapidly crosses the blood-brain barrier (Veryser et al., 2016). Human half-life, selectivity and metabolizing enzymes are uncharacterized. One facial serum showed no spilanthol passage through pig skin, suggesting local action (Savic et al., 2025).

Historical Context & Evolution

Spilanthes acmella has long been used in folk medicine across tropical South America, India and Southeast Asia, where chewing the flower heads numbs toothache and mouth sores, and its leaves are eaten as a vegetable in northern Brazil (Lee, 2026). Spilanthol was identified as the tingling principle.

Interest in skin rejuvenation arose because a compound that numbs nerves seemed likely to relax the small muscles behind expression lines. The French ingredient maker Gattefossé filed a patent in 2004, granted in the United States in 2009, claiming a botulinum toxin-like (wrinkle-relaxing injection) action based on a nerve–muscle cell culture (patent US7531193). Its branded extract was then marketed as a “natural Botox”.

Testing in people followed. In 2011, researchers at Indena, which makes a rival Sichuan-pepper-derived extract, used a spilanthol extract as a comparator and found no objective immediate lifting, although both extracts gave a modest longer-term wrinkle improvement (Artaria et al., 2011). Later studies by a Serbian manufacturer measured gradual changes in wrinkles, hydration and texture with skin-imaging instruments (Savic et al., 2025).

Opinion has therefore moved from an immediate injection-like claim toward viewing the extract as a mild, multifunctional cosmetic active. Neither view is final: the muscle-relaxing idea has never been tested directly in human facial muscle, and the gradual benefits still lack comparison against the same cream without the extract.

Expected Benefits

High 🟩 🟩 🟩

No benefit reaches High: each human outcome rests on a single randomized trial (skin, sexual function or dental sensitivity) or on uncontrolled cosmetic-panel studies, with no outcome replicated across controlled trials.

Medium 🟩 🟩

Gradual Reduction of Fine Lines and Wrinkles

Serums containing Acmella oleracea extract reduced wrinkle measurements around the eyes and mouth after 2 weeks of use. The strongest evidence is a randomized, reference-controlled, half-face trial using skin-topography imaging, supported by an earlier uncontrolled skin-replica study from the same group (Savic et al., 2025; Savic et al., 2021). Both studies were small, short and run by researchers affiliated with a cosmetics manufacturer. Neither compared the serum with the same base lacking the extract.

Magnitude: Wrinkle parameters fell by about 15% from baseline after 2 weeks (Savic et al., 2025).

Improved Skin Hydration and Surface Smoothness

The same randomized half-face trial reported higher skin moisture and smoothness, with less roughness and scaling around the eyes and mouth (Savic et al., 2025). Part of this effect may come from the moisturizing sugar-based emulsion base rather than the extract itself. The finding rests on one manufacturer-affiliated study in a small volunteer group.

Magnitude: Hydration rose 10–40% and smoothness about 15%, while roughness fell 20–30% and scaliness about 30% after 2 weeks (Savic et al., 2025).

Improved Erectile Function ⭕️ Not Central to Skin Rejuvenation

In a randomized, triple-blind, placebo-controlled trial in 298 men with erectile dysfunction symptoms, 500 mg of oral Spilanthes acmella extract daily for one month improved sexual-function scores and erection duration (Patnaik et al., 2022). This bears on male sexual health, not skin rejuvenation, and applies to oral use only. It is a single, short trial without independent replication.

Magnitude: The Men’s Sexual Health Questionnaire total score rose 17.24 points with the extract versus 4.72 with placebo after one month (Patnaik et al., 2022).

Local Numbing and Dental Pain Relief ⭕️ Not Central to Skin Rejuvenation

Spilanthol’s nerve-quieting action underlies the plant’s traditional toothache use. In a placebo-controlled randomized trial in 72 volunteers, a bioadhesive film containing Acmella oleracea extract, applied before tooth bleaching, produced the lowest post-bleaching tooth sensitivity (Silva et al., 2026). Added to a lidocaine-prilocaine cream, the extract gave only intermediate numbing of the mouth lining, below the anesthetic cream alone (Monteiro et al., 2025). This bears on oral and dental pain, not skin rejuvenation.

Magnitude: Differences in post-bleaching sensitivity between groups showed a very large effect size (ε² = 0.85, meaning group assignment explained most of the variation in scores), with the extract film lowest and placebo highest over 21 days (Silva et al., 2026).

Low 🟩

Immediate Expression-Line Relaxation ⚠️ Conflicted

An instant “Botox-like” effect is claimed from the originator’s cell-culture data (patent US7531193). In people, a spilanthol-rich extract gave no objective immediate lifting yet a modest longer-term wrinkle effect in a study by a rival-extract maker (Artaria et al., 2011). Net reading: an immediate injection-like effect is unsupported in humans.

Magnitude: No measurable immediate lifting occurred at the tested dose; the study reports no outcome figure for the spilanthol extract.

Firmer, Denser Skin in Multi-Ingredient Products

Uncontrolled studies of products pairing Acmella extract with retinol, or with Centella, ginger and ferulic acid, reported firmer, denser skin and lighter under-eye circles (Ye et al., 2022; Moldovan et al., 2017). The first was run by a skin-care company; Acmella’s share cannot be separated.

Magnitude: Skin elasticity (Cutometer R2) rose 13.0% over 6 weeks (Ye et al., 2022); ultrasound skin density rose from 9.21% to 12.50% over 8 weeks (Moldovan et al., 2017).

Speculative 🟨

Calming of Skin Inflammation

Spilanthol reduced inflammatory messengers in human skin cells (Huang et al., 2018) and eased chemically induced dermatitis in mice (Huang et al., 2019). Basis is cell and animal work only.

Antioxidant Protection

Acmella extracts are rich in polyphenols and flavonoids (plant antioxidant compounds) and scavenge free radicals in laboratory assays (Turcov et al., 2024). Basis is laboratory chemistry only.

Collagen and Elastin Support

A company’s eight-ingredient, Acmella-containing blend raised collagen and elastin in cultured skin cells (Feifei et al., 2025); extract improved collagen in injured rat tendons (Moro et al., 2021). Basis is cell and animal work only.

Antibacterial Activity ⭕️ Not Central to Skin Rejuvenation

A systematic review of 14 laboratory studies found Acmella extracts inhibit Staphylococcus aureus and other bacteria (Shuid et al., 2026). This bears on skin and oral infection, not ageing; basis is laboratory only.

Skin Wound Repair ⭕️ Not Central to Skin Rejuvenation

A film combining Acmella oleracea extract with another herbal oil sped wound closure and collagen formation in rats (Yamane et al., 2016). This bears on wound healing, not ageing; basis is animal work only.

Anti-Demodex Activity ⭕️ Not Central to Skin Rejuvenation

Spilanthol 3% killed Demodex (hair-follicle mites) in the laboratory as fast as 5% permethrin (an anti-mite medication) (Kara et al., 2024). This bears on rosacea (facial redness disorder), not ageing; basis is laboratory only.

Benefit-Modifying Factors

  • Genetic factors: No gene variants are known to change the response to topical spilanthol. Inherited barrier weakness (for example, filaggrin gene variants, which impair the skin’s protective protein layer) could raise penetration, but this remains unstudied.
  • Baseline skin status: Fine, movement-related lines and dry, rough skin show the most measurable change; deep folds from volume loss or sun damage lie outside the effect sizes reported in trials.
  • Sex differences: Published skin studies enrolled mainly or only women; no sex-specific efficacy data exist. Thicker male skin and stronger facial muscles could plausibly reduce visible effects, but this is untested.
  • Pre-existing conditions: Rosacea or mite-associated dermatitis could benefit from anti-mite and anti-inflammatory activity in theory; eczema-prone or reactive skin may not tolerate the tingling well enough to continue use.
  • Age: Trials enrolled mostly younger and middle-aged women (for example, 20–45 years in one study (Ye et al., 2022)). Older adults with thin skin and deep static wrinkles are unstudied and less likely to see visible change.

Potential Risks & Side Effects

High 🟥 🟥 🟥

No risk reaches High: human safety data come from small cosmetic tolerability panels, one oral trial and a single case report, not replicated controlled trials recording adverse events.

Medium 🟥 🟥

Tingling, Numbness and Taste Disturbance

Spilanthol stimulates sensory nerves, producing tingling, local numbness and extra saliva, the plant’s defining effect. Facial products applied near the lips can reach the mouth. In a randomized placebo-controlled oral trial of 500 mg extract daily, taste disturbance was the most common treatment-related adverse event, with no serious events (Patnaik et al., 2022). Effects are brief and reversible; facial serums were well tolerated in small panels (Savic et al., 2021).

Magnitude: Dysgeusia (altered taste) affected 3.94% of participants taking the oral extract (Patnaik et al., 2022); the frequency of tingling after topical use is not reported.

Low 🟥

Allergic Contact Dermatitis in Daisy-Family Allergy

Spilanthes acmella belongs to the Compositae (daisy) family, whose sesquiterpene lactones (plant compounds that trigger skin allergy) are recognized allergens. No Acmella-specific cases are published; risk is inferred from the family, and about one-third of relevant Compositae cases come from personal-care products (Punchihewa et al., 2022).

Magnitude: About 1% of European and 0.8% of North American patch-tested patients react to the sesquiterpene lactone mix (Paulsen, 2023); Acmella-specific rates are not reported.

Painful Lip Swelling

A single case report describes painful lip swelling after eating Spilanthes acmella flower buds sold as “Szechuan buttons” (Mumtaz et al., 2019). The mechanism, allergic or irritant, is unknown, and relevance to facial application is uncertain.

Magnitude: Not quantified in available studies. Only one case report exists, so no incidence can be estimated.

Speculative 🟨

Increased Skin Uptake of Co-Applied Substances

Spilanthol raised penetration of caffeine, testosterone and five mold toxins through excised human skin (De Spiegeleer et al., 2013). Basis is laboratory only; relevant when layering potent actives or using contaminated extracts.

Reproductive and Developmental Toxicity

Oral flower extract and spilanthol impaired fertility and caused embryo death and malformations in zebrafish (de Souza et al., 2020). Basis is animal work at oral doses; topical systemic exposure appears minimal.

Sex-Hormone Changes

Oral flower extracts raised testosterone and pituitary sex hormones in male rats (Sharma et al., 2011). Basis is animal work at oral doses; relevant mainly to androgen-sensitive conditions.

Increased Urine Output

An oral flower extract acted like a loop diuretic (a potent drug class that increases urine output) in rats, raising urine and sodium loss (Ratnasooriya et al., 2004). Basis is animal work at oral doses.

Risk-Modifying Factors

  • Genetic factors: No gene variants affecting drug response are known. An inherited tendency to eczema and allergy (atopy) may raise sensitization risk to plant allergens, based on data for other Compositae plants.
  • Baseline biomarkers: A positive patch test to sesquiterpene lactone mix or Compositae mix identifies people at higher allergy risk. No blood marker predicts topical reactions.
  • Sex differences: In one clinic series, all Compositae dermatitis cases traced to personal-care products occurred in women (Punchihewa et al., 2022), reflecting greater cosmetic exposure rather than proven biological susceptibility.
  • Pre-existing conditions: Eczema, rosacea, broken skin or a recent laser or peel increase penetration and irritation. Pregnancy and androgen-sensitive prostate cancer matter mainly for oral use.
  • Age: Older skin repairs its barrier more slowly, so irritation may last longer. Older adults are also likelier to take diuretics, relevant only to oral use.

Key Interactions & Contraindications

  • Topical prescription retinoids (vitamin A-derived drugs: tretinoin, adapalene, tazarotene): Caution. Spilanthol’s penetration enhancement may increase retinoid uptake and irritation (redness, peeling). Mitigation: applying them at different times of day and introducing one product at a time (De Spiegeleer et al., 2013).
  • Potent prescription topicals (clobetasol, hydroquinone): Monitor. Enhanced penetration could raise local side effects such as steroid-induced skin thinning or bleaching irritation. Mitigation: no layering on the same area at the same time.
  • Diuretics (furosemide, hydrochlorothiazide), oral Acmella only: Caution. Additive fluid and electrolyte loss is possible based on rat data. Mitigation: not relevant to topical use; high-dose oral extracts are the concern (Memorial Sloan Kettering monograph).
  • Antiandrogens (drugs that block male hormones: bicalutamide, flutamide, abiraterone), oral Acmella only: Caution. Testosterone rises in rats could oppose prostate cancer therapy. Mitigation: no oral use during treatment.
  • CYP2E1 (a liver enzyme that breaks down some anesthetics and alcohol) substrates (chlorzoxazone, isoflurane, sevoflurane): Monitor, theoretical; possibly altered drug levels or effects. Spilanthol inhibited CYP2E1 in laboratory tests, per the monograph above. Mitigation: disclosing oral use before surgery.
  • Over-the-counter topical anesthetics (lidocaine, benzocaine): Monitor. Additive numbness; Acmella has been combined with lidocaine-prilocaine in a topical anesthesia trial (Monteiro et al., 2025). Mitigation: no simultaneous use over large areas.
  • Over-the-counter exfoliants and retinol (glycolic acid, salicylic acid, retinol serums): Caution. Stacked irritation and deeper penetration through a thinned barrier. Mitigation: alternating evenings.
  • Daisy-family botanicals (chamomile, arnica, calendula, echinacea): Caution. Cross-sensitization can cause allergic dermatitis in Compositae-allergic people. Mitigation: patch testing each product.
  • Other tingling alkylamide extracts (Sichuan pepper, echinacea): Monitor. Additive tingling and numbness. Mitigation: one tingling active at a time.
  • Skin procedures (laser resurfacing, chemical peels, microneedling): Caution. Barrier disruption raises penetration and irritation. Mitigation: pausing use for 7–14 days after the procedure.
  • Botulinum toxin injections: No known interaction; mechanisms differ and no data show potentiation. Mitigation: none required.

Populations who should avoid Spilanthes acmella:

  • People with a positive patch test to sesquiterpene lactone mix or Compositae mix, or prior reactions to chamomile, arnica or ragweed
  • Pregnant or breastfeeding individuals (oral use; animal embryo toxicity)
  • Men with androgen-sensitive prostate cancer on antiandrogen therapy (oral use)
  • Anyone with active eczema, open wounds or skin within 7–14 days of ablative (skin-removing) laser, medium-depth peel or microneedling

Risk Mitigation Strategies

  • Home patch test before facial use: Twice-daily application to the inner forearm for 7 days, stopping at any redness, itching or swelling. Mitigates allergic contact dermatitis.
  • Formal testing for known plant allergy: Dermatologist patch testing with sesquiterpene lactone mix and Compositae mix, read at 48 and 96 hours, before any use. Prevents reactions in daisy-family-sensitized people.
  • Distance from lips and eye margins: Application at least 1 cm from the lip border and lash line. Reduces tingling, numbness, taste disturbance and lip swelling.
  • Staggered potent actives: Acmella in the morning, retinoids or acids in the evening. Reduces penetration-driven irritation.
  • Tested products: Products with documented microbial and mycotoxin (mold toxin) testing. Prevents enhanced skin uptake of contaminants.
  • Topical rather than oral use: Topical use limits systemic exposure. Avoids the hormonal, diuretic and reproductive signals seen with oral extracts in animals.
  • Procedure-related pauses: No use for 7–14 days after laser, peels or microneedling. Mitigates irritation from barrier disruption.

Therapeutic Protocol

  • Standard topical regimen: A serum or cream containing Acmella oleracea flower extract is applied to clean skin around the eyes, mouth and forehead once or twice daily; published studies ran 2–8 weeks.
  • Concentration: The originator patent (US7531193) specifies 0.1–10% dry extract, or 0.05–5% when pure spilanthol is used, with example formulas at 1–2% dry extract. Most retail products do not disclose concentration.
  • Competing approaches: Plant-extract serums (popularized by Gattefossé’s Gatuline Expression), synthetic peptide topicals such as acetyl hexapeptide-8 (Argireline, from Lipotec), and injected botulinum toxin (cosmetic use pioneered by Jean and Alastair Carruthers) differ in strength, cost and evidence depth.
  • Time of day: No timing studies exist. Evening application avoids tingling under makeup; morning use is typically paired with sunscreen, as the extract offers no ultraviolet protection.
  • Half-life: Oral spilanthol’s half-life in rats is about 1.2 hours; human skin kinetics are unknown. The muscle effect in cell culture reversed within 1 hour, suggesting any relaxation is short-lived.
  • Single vs split dosing: Twice-daily application is the common cosmetic pattern; no study compares once-daily with twice-daily use.
  • Genetic factors: No gene variants affecting drug response guide dosing. People with inherited barrier weakness or atopy may start with lower-strength products applied every other day.
  • Sex differences: Nearly all volunteers were women; no sex-specific dosing data exist, and men’s thicker skin could plausibly need longer use to show change.
  • Age: Studies enrolled mainly adults under 50; no age-specific dosing exists. Older users often combine Acmella with established agents because deep static wrinkles respond little.
  • Baseline status: Fine movement lines and dry skin show the most change; deep folds and volume loss fall outside the plausible effect range.
  • Pre-existing conditions: Rosacea, eczema or recent procedures are typically approached with a patch test and a slower start of every other day for the first week.
  • Oral use: Oral extracts (for example, 500 mg capsules) are marketed for sexual function, not skin; no study supports oral use for skin rejuvenation.

Discontinuation & Cycling

  • Duration: Use can be short-term or ongoing; cosmetic gains are expected to fade once application stops, as with other topical actives.
  • Withdrawal effects: None reported; no rebound worsening of wrinkles has been documented after stopping.
  • Tapering: Not required; the product can be stopped at once.
  • Cycling: No evidence supports cycling. Repeated application caused only limited loss of the tingling sensation, and no data show fading efficacy with continuous use (Artaria et al., 2011).
  • Stopping signals: Redness, itching, swelling or lip discomfort typically prompt stopping and patch testing.

Sourcing and Quality

  • Standardization: Spilanthol content varies with plant part, cultivation and extraction method, and the compound degrades over time. Products disclosing spilanthol content offer more predictable activity (Grymel et al., 2023).
  • Label names: Ingredient lists name it “Acmella Oleracea Extract” or “Spilanthes Acmella Flower Extract”; position near the top suggests meaningful concentration.
  • Branded ingredient: Gatuline Expression, supplied by Gattefossé, is the best-known standardized extract; the serum tested in the randomized facial trial came from Serbian manufacturer DCP Hemigal.
  • Third-party testing: Mold-toxin and microbial testing matters because spilanthol increases skin uptake of contaminants; manufacturers certified to ISO 22716 (cosmetic good manufacturing practice) offer greater assurance.
  • Formulation and packaging: Airtight, opaque packaging protects spilanthol from degradation; emulsions and newer ultra-fine emulsion gels aim to improve stability and delivery.

Practical Considerations

  • Time to effect: Hydration and texture changes appeared within 2 weeks in trials; firmness changes in multi-ingredient products were measured at 6–8 weeks.
  • Common pitfalls: Expecting injection-level results, judging potency by tingle strength, applying to lips or eyelid rims, layering with strong acids on irritated skin, and buying products with undisclosed extract concentration.
  • Regulatory status: Sold as a cosmetic ingredient in the United States and European Union without pre-market approval; claims of muscle relaxation would make it an unapproved drug in the United States. It is not an approved medicine anywhere.
  • Cost and accessibility: Widely available in mid-priced serums. Neither cosmetic topicals nor cosmetic botulinum toxin are reimbursed by insurers, so no payer incentive favors either option.

Interaction with Foundational Habits

  • Sleep: None direct. Topical use has no known sedative or stimulant effect; injected spilanthol enters the brain in mice, but facial application yields minimal systemic exposure. Evening application does not disturb sleep in reported studies.
  • Nutrition: None known for topical use. The leaves are eaten as a vegetable (jambu) in northern Brazil without reported skin effects. A diet rich in colorful plant foods may complement antioxidant claims indirectly; no nutrient depletion is known.
  • Exercise: None direct. Sweat can carry product toward the eyes and amplify stinging, so application after post-workout cleansing is practical. No effect on muscle hypertrophy or performance is expected from topical use.
  • Stress management: Indirect. Stress-related frowning and squinting repeatedly fold the skin and drive expression lines, potentially blunting any topical benefit; no effect on cortisol is known.

Monitoring Protocol & Defining Success

Baseline testing before starting consists of standardized facial photographs at rest and during expression, an optional instrumental skin-hydration reading at a dermatology or aesthetic clinic, and a home patch test. People with a history of daisy-family plant allergy undergo formal dermatologist patch testing first. No blood tests are required for topical use, and conventional and functional targets do not differ for these measures.

Ongoing monitoring follows the timepoints used in trials: repeat photographs and, where available, hydration readings at 2 weeks, 6–8 weeks, then every 3–6 months while use continues. Success is defined as visible softening of fine lines or smoother, better-hydrated skin compared with the person’s own baseline, without irritation. No meaningful change after 8 weeks of consistent use suggests limited individual benefit.

Biomarker Optimal Functional Range Why Measure It? Context/Notes
Standardized facial photographs No established target; track change from own baseline Documents wrinkle change Same lighting, camera distance and time of day; include resting, frowning and smiling views
Skin hydration (corneometry) No established functional target; track rise from own baseline in device units Objective moisture change Corneometry is an electrical measure of surface-skin water content; measure after 20 minutes at room temperature, without products for 12 hours
Wrinkle severity grade Improvement of at least 1 grade from baseline Standardizes visual change Scored on a validated photographic crow’s-feet or forehead-line scale by the same rater
Patch test: sesquiterpene lactone mix and Compositae mix Negative Screens for daisy-family allergy Dermatologist-applied; read at 48 and 96 hours; needed only with a history of plant or cosmetic allergy
Home use test No reaction after 7 days Screens for irritation or allergy Twice-daily application to the inner forearm

Qualitative markers:

  • Perceived smoothness and softness of skin around the eyes and mouth
  • Visibility of fine lines in morning light and makeup settling into lines
  • Skin comfort: absence of tightness, stinging or persistent tingling
  • Tolerability: no redness, itching, swelling or lip discomfort

Emerging Research

  • No skin-ageing trials registered: As of September 2026, ClinicalTrials.gov lists no Spilanthes acmella skin-rejuvenation trial. Registered studies are dental or pain trials: bleaching-sensitivity film, 72 participants, Phase 3, completed (NCT07478640); dentin-hypersensitivity (exposed-root tooth pain) gel, 100, completed (NCT06971783); oral-film safety, 72, status unknown (NCT05219747); rectal-examination analgesia gel, 150, Phase 1, completed (NCT05141864).
  • Topical skin antisepsis and numbing: NCT02792972 is a completed randomized trial in 60 healthy volunteers applying Acmella extract to skin before blood draws, with pain score and skin microflora as primary outcomes; no results are posted, though they would inform skin tolerability.
  • Mouth-ulcer film: NCT06622213 is a Phase 2 randomized trial of 72 participants comparing mucoadhesive films (which stick to the mouth lining) with or without Acmella extract against triamcinolone (a steroid), measuring ulcer size and pain; not yet recruiting.
  • Delivery technologies: Ultra-fine emulsion gels (Spinozzi et al., 2025) and co-delivery with ginger extract (Magnano et al., 2026) could increase local exposure, potentially strengthening efficacy but also raising sensitization and penetration concerns.
  • Testing the “Botox-like” claim: The null immediate-lifting result of Artaria et al., 2011 remains unreplicated; independent trials comparing the same cream with and without extract could strengthen or weaken the case.
  • Anti-mite applications: Kara et al., 2024 proposed testing 3% spilanthol in patients for mite-associated skin disease such as rosacea, which could extend relevance to facial redness.
  • Contaminant penetration: De Spiegeleer et al., 2013 showed spilanthol increases skin uptake of mold toxins, a safety question that product-level testing studies could weaken or strengthen.

Conclusion

Spilanthes acmella is a tingling, numbing tropical herb whose flower extract is sold as a plant-based skin-care ingredient for smoothing lines around the eyes and mouth. For health-focused adults already using sunscreen, vitamin A creams or professional treatments, the human evidence points to modest, gradual improvements in fine lines, skin moisture and surface texture over a few weeks of regular use. The popular idea that the extract works like a wrinkle-relaxing injection rests mainly on laboratory work and was not borne out when tested directly on people, and claims about collagen building, calming inflammation and antioxidant protection remain at the laboratory stage.

The evidence base is thin. It consists of a handful of small, short studies, most without a comparison against the same cream lacking the extract, and most carried out by companies that make or sell the extract or rival ingredients. Independent replication is absent, and results from products containing several active ingredients cannot be credited to the plant alone.

Skin safety appears favorable in the small groups studied. The main concerns are the expected tingling and numbness, a possible allergy in people sensitive to daisy-family plants, and the extract’s ability to carry other substances deeper into the skin. Signals about hormones, fluid loss and pregnancy come from animal studies of oral extracts and have little bearing on a facial serum. Overall, the extract is a low-risk addition whose benefits remain modest and uncertain.

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