Microamps and Milliamps, What the Output Numbers Actually Mean
Medically reviewed by
4 independent reviewers
Andrew Conrad Barile, PT, DPT
Doctor of Physical Therapy (DPT) | Licensed Physical Therapist (PT) | CEO and Founder, Xtreem Pulse LLC
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Dr. Andrew Conrad Barile is a Doctor of Physical Therapy and the CEO and Founder of Xtreem Pulse LLC, the engineering company behind PureLift. He earned his Doctorate in Physical Therapy from Daemen College and is a licensed physical therapist.
He brings over two decades of clinical and entrepreneurial experience across physical therapy, craniosacral therapy and medical device innovation, built on a working knowledge of human anatomy and muscle physiology.
For PureLift LAB he reviews how current is delivered across all ten levels, from sub-sensory nanocurrent and skin-level microcurrent to motor-level EMS, and how the Infuse pass fits into the same ten-minute routine.
Bertica M. Rubio, M.D.
Board-Certified Physician, Dartmouth Medical School | Medical Director, Antiaging Regenerative Medicine Clinic
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Dr. Bertica M. Rubio is a board-certified physician and Medical Director of the Antiaging Regenerative Medicine Clinic in Redlands, California. She earned her Doctor of Medicine from Dartmouth Medical School and completed her pediatrics residency at UC Irvine Medical Center.
With decades of clinical experience, she specialises in age management medicine, regenerative medicine, wound healing and growth factor therapies, and her practice integrates evidence-based medical science with advanced aesthetic treatment.
For PureLift LAB she reviews articles for medical accuracy across the whole dial, from the gentle nanocurrent and microcurrent settings through to muscle-level EMS and the Infuse pass.
Daniel Grinberg, MD, FACS
Board-Certified Otolaryngologist | Head and Neck Surgeon | Fellow, American College of Surgeons | Mount Sinai
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Daniel Grinberg, MD, FACS is a board-certified otolaryngologist and head and neck surgeon at ENT and Allergy Associates in West Nyack, New York. He earned his medical degree from Columbia University College of Physicians and Surgeons.
He completed his otolaryngology residency at New York University Medical Center, serves as Assistant Clinical Professor at Mount Sinai School of Medicine, and is a Fellow of both the American College of Surgeons and the American Academy of Otolaryngology.
For PureLift LAB he brings a wider clinical lens, connecting at-home facial stimulation from microcurrent to EMS to the anatomy underneath, with the same rigour we apply to every device specification.
Prof. Dr. med. Ivo Buschmann
Chair of Angiology, Medizinische Hochschule Brandenburg | Clinic Director, University Clinic for Angiology
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Prof. Dr. med. Ivo Buschmann is Chair of Angiology at the Medizinische Hochschule Brandenburg Theodor Fontane and Clinic Director of the University Clinic for Angiology at the Brandenburg University Hospital.
He trained at the University of Hamburg, was a Max Planck Society Fellow at the Max Planck Institute for Heart and Lung Research, and held senior consultant posts at the Charite Universitatsmedizin Berlin before his appointment as Chair in 2016.
One of Europe's leading authorities on arteriogenesis, with over 150 peer-reviewed publications and US and EU patents, he reviews for PureLift LAB how the evidence on electrical stimulation is read and where its limits lie.
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A milliamp is a thousand microamps, so a device at 7 mA and a device at 500 microamps are not neighbours on a scale, they are in different bands entirely.
This article compares the two on what decides the result you actually see, such as:
- The arithmetic
- What the gap buys
- What the gap does not buy
- Why a bare milliamp figure is incomplete
- Reading a spec sheet
and many more!
It does not decide which device is better, because the two bands are aimed at different jobs.
Key Points:
1 milliamp equals 1,000 microamps, written µA.
Published microcurrent figures sit between roughly 170 and 680 microamps, all below the motor threshold.
PureLift publishes 7 mA at 500 ohms for Face and Pro, 7.7 mA for Pro Edition, and 9 mA for Pro Plus and GLOW.
A milliamp figure with no impedance stated is half a number, which is why 500 ohms appears alongside ours.
Higher current is not automatically better; it is better only if muscle contraction is what you came for.
The arithmetic
Current is measured in amps, and facial devices work in fractions of one. A milliamp is a thousandth of an amp and a microamp is a millionth, so one milliamp contains a thousand microamps.
Put the published numbers side by side and the scale becomes obvious. NuFACE's Trinity+ figures, taken from FDA record K201906, sit between 170 and 200 microamps. ZIIP Halo publishes 309 microamps. Therabody's TheraFace PRO publishes 500. FOREO's BEAR 2 publishes 680.
PureLift Face publishes 7 mA at 500 ohms, which is 7,000 microamps. Pro Plus and GLOW reach 9 mA, which is 9,000.
What the gap buys
Ward's work describes three thresholds as current rises. At the lowest, nothing is felt. Higher, you feel a tingle. Higher still, the nerve fires and the muscle contracts (PMID 19095805).
Every published microcurrent figure in the list above sits below that third threshold. That is not an accident or a cost saving; it is the category definition, and a microcurrent device is supposed to stay there.
Crossing into the third band is what EMS is for, and it is the only way to make the muscle do work. Kavanagh and colleagues followed 108 women over 12 weeks and measured an 18.6 percent increase in cheek muscle thickness with motor-level stimulation (10.1111/jocd.12007); that outcome is unavailable at 500 microamps because the muscle never contracts.
What the gap does not buy
Higher current is not a general quality score. The research in the microamp band is about cellular activity, fibroblast signalling and dermal circulation, and those are skin-level mechanisms that do not need a contraction and are not improved by one.
So a device that publishes 309 microamps is not failing to reach 9 mA; it is doing a different job. If your concern is texture and tone rather than contour, the low band is the right band, and paying for EMS you will never switch on is not clever shopping.
PureLift's answer is to put both on one dial. Levels 1 and 2 sit in nanocurrent and microcurrent territory, level 3 crosses the motor threshold, and levels 3 to 10 are EMS, so the band is a choice you make at the moment of use rather than at the moment of purchase.
Why a bare milliamp figure is incomplete
Current depends on the resistance it meets, so an output figure means little without the load it was measured against. Skin impedance varies with how damp it is, where on the face you are working, and whose face it is.
That is why our figures carry 500 ohms alongside them, and why a brand publishing a bare number is telling you less than it appears to.
Pulse width matters too. PureLift Face and Pro use a 4 microsecond pulse, and how long each pulse lasts changes what a given peak current actually does.
Maffiuletti's work makes the underlying point that a dial setting is not the same as the tension actually produced in the muscle (PMID 29233625), which is also why comparing two brands by their level numbers is meaningless.
Reading a spec sheet
Ask for four things: the maximum current, the impedance it was measured at, the pulse width, and whether the frequency is fixed or varied.
A brand that publishes all four is giving you something to check. A brand that publishes none is asking for trust instead, and a mode name is not a specification.
For the full breakdown of which technology sits where on the dial, see how the nine PureLift technologies work.