Microamps Explained, What 335, 500 and 680 Really Mean
Medically reviewed by
4 independent reviewers
Andrew Conrad Barile, Fisioterapeuta, Doctor en Terapia Física
Doctorado en Terapia Física (DPT), Fisioterapeuta Licenciado (PT)
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El Dr. Andrew Conrad Barile es Doctor en Terapia Física y CEO y Fundador de Xtreem Pulse LLC. Obtuvo su Doctorado en Terapia Física en Daemen College y aporta más de dos décadas de experiencia clínica y empresarial en terapia física pediátrica, terapia craneosacral e innovación en dispositivos médicos. Su profundo conocimiento de la anatomía humana, la fisiología muscular y la tecnología terapéutica ofrece un enfoque invaluable respaldado por la ciencia para la rejuvenecimiento facial y soluciones antienvejecimiento.
Bertica M. Rubio, M.D.
Director Médico, Clínica de Medicina Regenerativa y Antienvejecimiento | Médico Certificado por la Junta | Escuela de Medicina de Dartmouth
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La Dra. Bertica M. Rubio es una médica certificada y Directora Médica de la Clínica de Medicina Regenerativa y Antienvejecimiento en Redlands, California. Obtuvo su licenciatura en Ciencias en la Universidad Loyola Marymount y su título de Doctora en Medicina en la Escuela de Medicina de Dartmouth (Geisel School of Medicine). Completó su residencia en pediatría en el Centro Médico UC Irvine.
Con décadas de experiencia clínica, la Dra. Rubio se especializa en medicina para el manejo de la edad, medicina regenerativa, cicatrización de heridas y terapias con factores de crecimiento. Su práctica integra la ciencia médica basada en evidencia con tratamientos estéticos y regenerativos avanzados, ayudando a los pacientes a alcanzar una salud óptima y vitalidad juvenil.
La Dra. Rubio siente pasión por educar a los pacientes sobre la ciencia detrás del cuidado de la piel, el rejuvenecimiento facial y las tecnologías no invasivas como EMS (Estimulación Eléctrica Muscular) para el tonificado facial. Sus artículos para PureLift LAB combinan un conocimiento médico riguroso con orientación práctica para lograr resultados reales y duraderos.
Daniel Grinberg, MD, FACS
Otorrinolaringólogo y cirujano de cabeza y cuello certificado | Miembro, Colegio Americano de Cirujanos | Profesor clínico asistente, Escuela de Medicina Mount Sinai
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Daniel Grinberg, MD, FACS, es un otorrinolaringólogo certificado por la junta y cirujano de cabeza y cuello en ENT and Allergy Associates en West Nyack, NY. Obtuvo su título de médico en la Facultad de Médicos y Cirujanos de la Universidad de Columbia, completó su residencia en Otorrinolaringología en el Centro Médico de la Universidad de Nueva York y es profesor clínico asistente en la Escuela de Medicina Mount Sinai. Es miembro de la American College of Surgeons y de la American Academy of Otolaryngology.
La perspectiva quirúrgica de cabeza y cuello del Dr. Grinberg ofrece a los lectores de PureLift LAB una visión clínica más amplia, conectando la práctica de EMS en casa con la anatomía médica subyacente con el mismo rigor científico que aplicamos a cada especificación del dispositivo.
Prof. Dr. med. Ivo Buschmann
Cátedra de Angiología, Hochschule Médica de Brandeburgo | Director de Clínica, Clínica Universitaria de Angiología, Hospital Universitario de Brandeburgo | Ex Consultor Senior, Charité Universitätsmedizin Berlín
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El Prof. Dr. med. Ivo Buschmann es Catedrático de Angiología en la Medizinische Hochschule Brandenburg Theodor Fontane (MHB) y Director Clínico de la Clínica Universitaria de Angiología en el Hospital Universitario de Brandeburgo. Completó su formación médica en la Universidad de Hamburgo, fue becario de la Sociedad Max-Planck en el Instituto Max-Planck de Investigación Cardiaca y Pulmonar, y ocupó cargos de consultor senior en la Charité Universitätsmedizin Berlin Campus Virchow antes de ser nombrado Catedrático en la MHB en 2016.
El Prof. Buschmann es una de las principales autoridades europeas en arteriogénesis — el crecimiento y remodelación de los vasos sanguíneos impulsados por el flujo — con más de 150 publicaciones revisadas por pares y varias patentes en EE. UU. y la UE sobre dispositivos que estimulan el crecimiento de vasos colaterales mediante terapia controlada de tasa de cizalladura. Su investigación conecta la estimulación mecánica y eléctrica con la adaptación vascular, la microcirculación y la perfusión tisular.
Las contribuciones del Prof. Buschmann aportan a los lectores de PureLift LAB una perspectiva de biología vascular que complementa nuestra autoría clínica, de fisioterapia y de anatomía quirúrgica existente — explicando cómo la estimulación EMS activa no solo los músculos faciales sino también la microcirculación que los abastece, y por qué la administración inteligente es tan importante a nivel del flujo sanguíneo como en la contracción muscular.
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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.