Microamps Explained, What 335, 500 and 680 Really Mean
Medically reviewed by
4 independent reviewers
Andrew Conrad Barile, kinésithérapeute, DPT
Doctorat en physiothérapie (DPT), physiothérapeute agréé (PT)
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Le Dr Andrew Conrad Barile est docteur en physiothérapie et PDG ainsi que fondateur de Xtreem Pulse LLC. Il a obtenu son doctorat en physiothérapie à Daemen College et possède plus de vingt ans d'expérience clinique et entrepreneuriale en physiothérapie pédiatrique, thérapie craniosacrale et innovation en dispositifs médicaux. Sa profonde connaissance de l'anatomie humaine, de la physiologie musculaire et des technologies thérapeutiques offre une approche scientifique précieuse pour le rajeunissement du visage et les solutions anti-âge.
Bertica M. Rubio, M.D.
Directeur Médical, Clinique de Médecine Régénérative Anti-âge | Médecin Certifié par le Conseil | École de Médecine de Dartmouth
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Le Dr Bertica M. Rubio est une médecin certifiée et directrice médicale de la clinique de médecine régénérative anti-âge à Redlands, en Californie. Elle a obtenu son Bachelor of Science à l'Université Loyola Marymount et son Doctorat en médecine à la Dartmouth Medical School (Geisel School of Medicine). Elle a effectué sa résidence en pédiatrie au UC Irvine Medical Center.
Forte de plusieurs décennies d'expérience clinique, le Dr Rubio est spécialisée en médecine de gestion du vieillissement, médecine régénérative, cicatrisation des plaies et thérapies par facteurs de croissance. Sa pratique intègre la science médicale fondée sur des preuves avec des traitements esthétiques et régénératifs avancés, aidant les patients à atteindre une santé optimale et une vitalité juvénile.
Le Dr Rubio est passionnée par l'éducation des patients sur la science derrière les soins de la peau, le rajeunissement du visage et les technologies non invasives comme l'EMS (stimulation électrique musculaire) pour le tonus facial. Ses articles pour PureLift LAB allient connaissances médicales rigoureuses et conseils pratiques pour obtenir des résultats réels et durables.
Daniel Grinberg, MD, FACS
Otolaryngologiste et chirurgien de la tête et du cou certifié par le conseil | Membre, American College of Surgeons | Professeur clinique adjoint, Mount Sinai School of Medicine
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Daniel Grinberg, MD, FACS, est un oto-rhino-laryngologiste certifié par le conseil et chirurgien de la tête et du cou chez ENT and Allergy Associates à West Nyack, NY. Il a obtenu son diplôme de médecine au Columbia University College of Physicians and Surgeons, a effectué sa résidence en oto-rhino-laryngologie au New York University Medical Center, et est professeur clinique adjoint à la Mount Sinai School of Medicine. Il est membre de l'American College of Surgeons et de l'American Academy of Otolaryngology.
La perspective chirurgicale de la tête et du cou du Dr Grinberg offre aux lecteurs de PureLift LAB une vision clinique élargie — reliant la pratique EMS à domicile à l'anatomie médicale sous-jacente avec la même rigueur scientifique que celle que nous appliquons à chaque spécification d'appareil.
Prof. Dr med Ivo Buschmann
Président d'Angiologie, Hochschule Medizinische Brandenburg | Directeur de clinique, Clinique universitaire d'angiologie, Hôpital universitaire de Brandebourg | Ancien consultant principal, Charité Universitätsmedizin Berlin
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Le Prof. Dr. med. Ivo Buschmann est titulaire de la chaire d'angiologie à la Medizinische Hochschule Brandenburg Theodor Fontane (MHB) et directeur de la clinique universitaire d'angiologie à l'hôpital universitaire de Brandebourg. Il a effectué sa formation médicale à l'Université de Hambourg, a été boursier de la Société Max-Planck à l'Institut Max-Planck de recherche sur le cœur et les poumons, et a occupé des postes de consultant principal à la Charité Universitätsmedizin Berlin Campus Virchow avant d'être nommé titulaire de la chaire à la MHB en 2016.
Le Prof. Buschmann est l'une des principales autorités européennes en arteriogenèse — la croissance et le remodelage des vaisseaux sanguins induits par le flux — avec plus de 150 publications évaluées par des pairs et plusieurs brevets américains et européens sur des dispositifs stimulant la croissance des vaisseaux collatéraux par une thérapie contrôlée du taux de cisaillement. Ses recherches relient la stimulation mécanique et électrique à l'adaptation vasculaire, à la microcirculation et à la perfusion tissulaire.
Les contributions du Prof. Buschmann apportent aux lecteurs de PureLift LAB une perspective en biologie vasculaire qui complète notre expertise clinique, en physiothérapie et en anatomie chirurgicale — expliquant comment la stimulation EMS engage non seulement les muscles faciaux mais aussi la microcirculation qui les alimente, et pourquoi une administration intelligente est aussi importante au niveau du flux sanguin qu'à celui de la contraction musculaire.
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A microamp is a millionth of an amp, every consumer microcurrent device quotes a few hundred of them, and all of those figures sit in the same band well below the level that moves a muscle.
This article explains what is actually happening, such as:
- what a microamp is, in terms you can picture
- why 335 and 680 are closer together than they look
- where the sensory and motor thresholds actually sit
- what the missing load and pulse width would tell you
- what each band of current can and cannot do
and many more!
The unit is simple; what brands leave off around it is where the difficulty lives.
Key Points:
A microamp is one millionth of an amp, and a milliamp is one thousandth, so 1 mA is 1,000 microamps.
Consumer microcurrent devices publish figures between about 200 and 680 microamps, all inside the same sub-sensory to barely-sensory band.
Muscle contraction needs current in the milliamp range, which is roughly an order of magnitude or more above any of those figures.
A current figure means little without the load it was measured at, because current through skin depends on resistance.
Pulse width matters as much as current, since tissue responds to charge, which is current multiplied by duration.
What the unit actually is
An amp measures the rate at which electrical charge flows. A milliamp is a thousandth of an amp, and a microamp is a millionth, so a thousand microamps make one milliamp.
For scale, a household circuit breaker trips somewhere around 13,000 to 30,000 milliamps, a TENS unit for pain typically works in the tens of milliamps, and a microcurrent facial device works in the hundreds of microamps, which is well under a single milliamp.
So when a brand quotes 500 microamps, it is quoting half of one milliamp. The number sounds substantial because the unit is small, which is part of why the unit gets used.
Why 335 and 680 are closer than they look
Across the devices that publish anything, Solawave gives about 200 microamps, ZIIP publishes 309, NuFACE files 335 with the FDA, 7E publishes 350 at 500 ohms, Therabody gives 500, and FOREO publishes 680.
Doubling from 335 to 680 sounds like a large difference, and in terms of what physically happens in tissue both figures sit comfortably inside the same band, below the level at which a motor nerve depolarises.
Ward and colleagues described the thresholds separating sub-sensory, sensory and motor stimulation, and the practical consequence is that moving from 335 to 680 microamps changes how much you feel rather than what category of effect you get.
7E Wellness states the point plainly in its own FAQ: true microcurrent is sub-sensory and cannot cause a physical or visual manipulation of the muscle. That is a manufacturer describing its own product accurately.
Where the motor threshold sits
To make a facial muscle contract, the current has to depolarise the motor nerve supplying it, and that takes current in the milliamp range rather than the microamp range.
Ya-Man's FDA filing for the Medi Lift PLUS publishes 3.22 mA at 500 ohms, which is about 3,220 microamps. PureLift publishes 7 mA at 500 ohms on Face and Pro, 7.7 mA on Pro Edition and 9 mA on Pro Plus and GLOW.
Kavanagh and colleagues measured an 18.6 percent increase in cheek muscle thickness across 108 women over twelve weeks using motor-level stimulation, which is the band those milliamp figures sit in rather than the microamp band.
None of that makes microcurrent useless. Avendano-Coy and colleagues reviewed microcurrent in wound healing and found measurable effects at sub-motor intensities, which is the honest case for the band: real effects at skin level, not muscle work.
The two numbers that are missing
The first is the load. Current through skin depends on the resistance it meets, so the same device measured into 500 ohms reads differently from the same device measured into 10,000 ohms, and both readings are true.
Of 33 devices we track, six publish an output figure on their own page and two state the load, which means most of the microamp figures in this market cannot be compared with each other at all.
The second is pulse width. Tissue responds to charge, which is current multiplied by how long each pulse lasts, so a device at 500 microamps with a long pulse delivers far more charge than one at 500 microamps with a short one.
7E's filing for the MyoLift QT gives pulse durations measured in hundreds of thousands of microseconds at frequencies below one hertz, while our devices run a 4 microsecond pulse at a much higher current. Those are entirely different delivery strategies that a single microamp figure hides.
What each band can do
Nanocurrent and low microcurrent, below roughly 100 microamps, is sub-sensory territory where you feel nothing and the claimed effects are cellular.
Microcurrent from roughly 100 to 1,000 microamps is where most consumer devices sit, producing skin-level effects and a mild tingle at the upper end.
Above about 1 milliamp, with the right pulse and frequency, you enter the band where the muscle responds and you can see the contraction in the mirror.
Which band your device occupies decides what is available to you, and the published figures for 33 devices will tell you where yours sits.
How to use the number when shopping
Treat a bare microamp figure as a rough indication of sensation rather than as a specification.
Ask for the load in the same breath, and treat a brand that cannot answer as having told you something anyway.
Ask for pulse width, which almost nobody publishes and which changes the picture completely.
And decide first which band you actually need, because a buyer who wants skin-level effects is well served by a good microcurrent device, while a buyer who wants contour change is not, whatever the microamp figure says.
This article sits inside our full map of the category, where we set out all 33 devices we track, what each one carries and what each brand publishes: Nine Technologies on One Dial, What the Rest of the Market Actually Carries.