TENS / Microcurrent / FSM

TENS, microcurrent, and frequency-specific microcurrent (FSM) deliver weak electrical current to modulate nerve and pain signalling. They sit in the Electroceuticals / Bioelectronic Medicine family and are evidence-supported for pain — conventional bioelectric stimulation with a real, if modest, evidence base. This is a class record: brands are examples inside it, not the subject of it. One brand family has been split out: the “adaptive” SCENAR / DENAS devices now have their own entry, because their specific adaptive claim was tested and not shown — a different verdict from the class's, and one that should not ride on the class grade.

The real substrate — modulating nerve and pain signalling

The mechanism is conventional and well-grounded. Weak electrical current modulates nerve and pain signalling through recognised routes — gate-control at the spinal level and endogenous opioid release. These are dosed, measurable interventions with a defined target: a real current, a real nerve, a plausible analgesic pathway. That grounding is exactly what separates this entry from the “energy” devices elsewhere in the atlas.

Claim vs evidence — grade A/B, but a small effect

The evidence splits by claim, and honesty about the size of the effect matters as much as its direction. For pain, TENS is genuinely supported — grade A/B — but the analgesic effect is weak: under 1 point on a 0–10 pain scale in chronic low-back-pain meta-analyses. It is real bioelectric medicine, not marketing; it is also not a large effect, and the page says so plainly. A Cochrane overview of reviews of TENS for chronic pain (an overview of Cochrane Reviews, 2019) found the underlying evidence largely low-quality and often inconclusive; a comparative-efficacy review (2023) reaches the same narrow reading. The moment the claim broadens past pain — to systemic or disease indications — the grade falls to C or lower.

The split — why SCENAR / DENAS left this record

SCENAR and DENAS are TENS-family stimulators, and as such they share this record's real substrate. What they added on top was a distinct claim: that tuning the output to the skin's changing impedance (“adaptive” stimulation) produces an advantage over ordinary TENS. That specific claim was put to a single-blind randomized trial — and the active and sham arms reduced pain equally. So the adaptive advantage sits in a different tier from the class's analgesic base, and it has been given its own entry to keep the two verdicts from being conflated. The class keeps its narrow, cleared, small-effect analgesia; the brand's adaptive claim does not inherit it.

Why this tier — three independent axes

This entry is Evidence-supported, but the support is indication-bound and modest. Keep the axes separate. Plausibility is high for analgesia and weak for systemic claims. Grade is A/B for pain (small effect) and C or lower beyond it. Tier follows the claim, not the hardware — the pain indication sits in the supported tier, while “whole-body” or disease claims do not. A device can be genuinely, if mildly, effective for one thing and unproven for another without contradiction.

Regulatory by jurisdiction

In the US, TENS is FDA-cleared for OTC analgesia, with the explicit caveat that a systemic overclaim is FTC-actionable. The devices are CE marked in the EU, and TENS units are registered in Russia and ARTG-listed in Australia. As always, a clearance is market access for the cleared use — here, pain — and confers nothing on claims that reach past it. (The SCENAR-specific 510(k) and ARTG listing are covered on the SCENAR / DENAS page.)

Keep vs set aside

Keep: conventional bioelectric stimulation with a real, modest evidence base for pain — the cleared analgesic indications are justified, with the effect size stated plainly (under 1 point on 0–10). Set aside: the “quantum” framing, the systemic or disease claims beyond pain, and any assumption that a brand's extra claim (the SCENAR/DENAS “adaptive” advantage) inherits the class's grade. The analgesia is real and small; the universal-healing story layered on top is not.