Benefits
Sexual function and performance scores in men
In a placebo-controlled trial in men with erection difficulties, 500 mg a day of a branded jambu extract for one month raised questionnaire scores for sexual function and self-reported erection duration more than placebo. The men's studies come from one research group using a single product, and have not been repeated by independent teams.
Serum testosterone levels in men
In a double-blind placebo-controlled trial in men with erection difficulties and low testosterone, three months of 500 mg a day raised serum testosterone more than placebo, with the difference still present three months after stopping. A separate uncontrolled follow-up reported a similar rise. All of this work used one branded extract from one group.
Muscle size and strength during resistance training
In a placebo-controlled trial in healthy men, 500 mg a day for three months alongside structured weight training was followed by larger increases in arm, chest and thigh measurements and in bench-press and squat loads than placebo, with total and free testosterone also higher. The effect sizes are large for a herbal extract and have not been reproduced elsewhere.
Activity on pain and inflammation pathways in laboratory studies
Jambu alkylamides, best known for the tingling and numbing feel they give the mouth, act on local pain signaling and lower inflammation markers such as TNF-alpha and IL-1-beta in cell and animal models, in several studies applied locally rather than swallowed. These are laboratory findings and have not been confirmed as benefits in people.
Mechanism of action
Spilanthol acts on sensory nerves in the mouth
Laboratory work indicates spilanthol works much like the related Sichuan-pepper compound sanshool, which blocks two-pore-domain potassium leak channels on trigeminal sensory neurons. This depolarizes the nerves and produces the tingling, pungent and numbing sensation, and in mouse taste cells it heightened the response to sodium.
Absorbed from the gut in animal studies
After oral dosing in rats, spilanthol is absorbed from the intestine into the bloodstream, and in mice it crosses into the brain. This measured gut absorption is the rationale for swallowed capsules, though how much reaches target tissues in people, and at what dose, has not been established.
Proposed hormonal and anti-inflammatory actions
The men's trials report higher testosterone after supplementation, and cell and animal studies describe anti-inflammatory and local pain-blunting effects of jambu alkylamides. The biological steps that would link an oral extract to these outcomes in people have not been mapped, and one in vivo rat study found no effect on blood pressure.
Clinical trials
Randomized, triple-blind, placebo-controlled parallel-group trial at two centers in India of SA3X capsules (500 mg Spilanthes acmella) daily for one month, with an added observational cohort (Patnaik et al. 2022, Cureus)
448 sexually active men with symptoms of erectile dysfunction in the intention-to-treat analysis (152 SA3X, 146 placebo, 150 observational).
The total Men's Sexual Health Questionnaire score rose more with SA3X than placebo at one month (17.24 vs 4.72 points, P<0.001) and remained higher one month after stopping. Erectile function index scores and self-reported erection duration also rose. Dysgeusia, an altered taste, was the most common drug-related side effect (about 4%); no serious side effects were reported. The trial is from a single research group using one branded extract.
Double-blind, placebo-controlled parallel-group trial in India of SA3X capsules (500 mg Spilanthes acmella) daily for three months in men with erectile dysfunction and low testosterone, with follow-up to six months (Patnaik et al. 2022, Maedica (Bucur))
215 men with erectile dysfunction and low testosterone in the intention-to-treat analysis (105 SA3X, 110 placebo).
Serum testosterone rose more with SA3X than placebo at three months (adjusted change about 22 vs 2 ng/dL, P<0.001) and stayed higher three months after stopping. Sexual-function and erectile index scores and erection duration also rose. The testosterone effect differed by body-mass index, other health conditions, and use of erectile-dysfunction drugs. Dysgeusia (about 8%) was the main side effect. Same single research group and branded extract.
Randomized, placebo-controlled parallel-group trial in India of SA3X (spilanthol-standardized Spilanthes acmella) daily for three months in healthy men, with and without structured exercise (Mishra et al. 2025, J Complement Integr Med)
546 healthy men randomized to SA3X or placebo, each with or without a structured weight-training program.
Among exercising men, SA3X produced larger gains than placebo in arm, chest and thigh measurements and in bench-press and squat loads, and men taking SA3X without exercise also gained more muscle size than placebo. Total and free testosterone rose with SA3X while estradiol did not. No significant side effects were reported. The reported gains are unusually large for a herbal extract and come from one research group.
Randomized, placebo-controlled four-group trial in India of 500 mg spilanthol (SA3X) daily for three months in men with high blood lipids, with and without exercise (Mishra et al. 2024, J Complement Integr Med)
279 men with dyslipidemia randomized to SA3X or placebo, each with or without standardized weight-lifting exercise.
Both SA3X groups showed reductions in total cholesterol, triglycerides and LDL cholesterol versus placebo, but HDL (the protective cholesterol) also fell. The cholesterol drop reported with SA3X plus exercise, about 53%, is very large and hard to interpret. C-reactive protein and some other markers fell. Taste disturbance was the main side effect. Registered as CTRI/2021/05/033694; single research group and one branded extract.