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General regulatory information for lab, clinic and supply staff. It is not medical advice and does not say whether any patient should use a device; that is a prescriber’s decision.
Short answer
A bone stimulator, formally a non-invasive bone growth stimulator, is a prescription device that delivers electrical, magnetic or ultrasonic fields from outside the body to promote bone formation as an adjunct to fracture fixation or spinal fusion, or as a treatment for established nonunions or failed fusions (21 CFR 890.5870). Since 18 May 2026 the FDA regulates it as class II, not class III.
Definition and scope under 21 CFR 890.5870
The regulation, added to the Code of Federal Regulations by 91 FR 20362 on 16 April 2026, defines the device in one sentence: a prescription device that provides stimulation through electrical, magnetic, or ultrasonic fields, intended to be used externally to promote osteogenesis as an adjunct to primary treatments for fracture fixation and spinal fusion or as a treatment for established nonunions or failed fusions.
Four phrases in that definition do the work:
- Prescription device. It is not an over-the-counter product.
- Electrical, magnetic, or ultrasonic fields. These are the three modalities the regulation names.
- Used externally. A device placed inside the body falls outside this wording, which is why the regulatory name carries the word “non-invasive”.
- Adjunct, or treatment for established nonunions or failed fusions. The two stated uses are as an add-on to primary treatment, or for a nonunion or failed fusion that has already been established.
The FDA product codes attached to the device type are LOF and LPQ. In openFDA’s classification record (last updated 19 October 2026), code LOF is titled “Stimulator, Bone Growth, Non-Invasive”, device class 2, regulation number 890.5870, orthopedic specialty, with the same definition as the regulation. The record is a database listing, not guidance for care decisions, and openFDA says so itself.
What changed in 2026: class III to class II
| Date | Event | Source |
|---|---|---|
| 16 April 2026 | FDA final order 2026-07366, “Physical Medicine Devices; Reclassification of Non-Invasive Bone Growth Stimulators”, published in the Federal Register | Federal Register |
| 18 May 2026 | Order takes effect. Product codes LOF and LPQ, previously postamendments class III devices, become class II and are subject to premarket notification | Federal Register |
| 2026 | New regulation 21 CFR 890.5870 codifies the device and sets its special controls | 21 CFR 890.5870 |
For a supply or compliance reader, the practical meaning is that the device type now has a named regulation and a fixed list of special controls, and new devices of this type reach the market through premarket notification. For how that pathway works, see the guide to FDA 510(k) premarket notification and the comparison of FDA clearance versus approval.
How it is used in practice
The regulation describes use only in general terms: the device is applied externally, on prescription, either alongside primary treatment for a fracture fixation or spinal fusion, or for a nonunion or failed fusion that is already established. Patient-level matters belong to the prescriber and the manufacturer’s instructions for use, and are not covered here. The regulation does require that the instructions describe usage, duration and frequency, and that a patient can use the device based solely on reading them (see the labeling checklist below).
Types: modality, not brand
| Term people search | What the regulation text says |
|---|---|
| Bone stimulator, bone growth stimulator | Both describe the regulated device type, “non-invasive bone growth stimulator” |
| External bone growth stimulator | The definition says “used externally”, so “external” and “non-invasive” are covered by the same wording |
| Electrical, magnetic, ultrasonic | The three field types the definition lists; it does not list brand names or waveform sub-types |
| PEMF bone stimulator | A search label. The definition’s own wording covers “magnetic” fields and does not use the term PEMF |
| Exogen | A brand name. The regulation is written by device type and does not name brands, so it does not describe any one brand |
Where it matters for labs, clinics and supply decisions
Section (b) of the regulation makes the device class II with special controls. Read as a checklist, the controls say what evidence and testing a manufacturer must hold for this device type:
- Clinical data. Imaging data must demonstrate fusion at the treatment site.
- Non-clinical performance testing. Intended design outputs are delivered; thermal safety and reliability; signal characteristics within safe physiologic limits; device reliability for the expected use-life.
- Biocompatibility of patient-contacting components.
- Electrical safety and electromagnetic compatibility.
- Software verification and validation, with hazard analysis.
- Labeling comprehension testing. A patient must be able to use the device based solely on reading the instructions for use.
- Required labeling content, listed below.
What the labeling must include
- A warning against use on compromised skin or known skin sensitivities
- Warnings for patients with implanted medical devices
- A summary of the supporting clinical data and adverse events
- A clear device description
- Instructions on usage, duration and frequency
- Maintenance and safe disposal information
- Validated cleaning instructions for reusable components
- Warnings on user burns, electrical shock and skin irritation
- Risks and benefits
Staff reviewing documentation for a device of this type can use these lists to see what the instructions for use are required to contain. Unique device identifiers and adverse-event reporting follow the general device rules, covered in the guides to UDI medical device requirements and Medical Device Reporting. For the wider classification system, see FDA medical device regulations: classification, 510(k) and PMA and what is a medical device.
Common misunderstandings
- “Class II means it is proven to heal bones.” Class II describes the regulatory controls attached to the device type. It is not a statement about how well any one device works for any one patient.
- “It is an over-the-counter wellness product.” The regulation defines it as a prescription device.
- “It replaces fixation or fusion.” The definition describes use as an adjunct to primary treatment, or for established nonunions and failed fusions.
- “A brand name is a device category.” Brand and signal-type names are not the regulated category; the category is the non-invasive bone growth stimulator.
- “The old class III record still applies.” Devices under product codes LOF and LPQ were class III before the order took effect on 18 May 2026 and are class II now.
FAQ
What is a bone stimulator?
Under 21 CFR 890.5870, a non-invasive bone growth stimulator is a prescription device that provides stimulation through electrical, magnetic, or ultrasonic fields and is intended to be used externally to promote osteogenesis as an adjunct to primary treatments for fracture fixation and spinal fusion, or as a treatment for established nonunions or failed fusions.
Is a bone growth stimulator the same as a bone stimulator?
For regulatory purposes, yes. Both phrases describe the device type the FDA calls a “non-invasive bone growth stimulator”, product codes LOF and LPQ.
What FDA class is a bone stimulator?
Class II with special controls. Under final order 2026-07366, published on 16 April 2026 and effective 18 May 2026, these devices moved from postamendments class III to class II, subject to premarket notification.
Is Exogen a bone stimulator?
Exogen is a brand name. The regulation is written by device type and names no brands, so this page does not describe any brand’s product. Check a specific device’s labeling and FDA listing for its details.
Is a PEMF bone stimulator regulated differently?
The regulation groups electrical, magnetic and ultrasonic devices under one device type with one set of special controls. It does not use the term PEMF.
Can a bone stimulator be bought without a prescription?
The regulation defines the device as a prescription device.
Sources
All sources checked 30 October 2026.
- 21 CFR 890.5870, Non-invasive bone growth stimulator (added 91 FR 20362, 16 April 2026): https://www.law.cornell.edu/cfr/text/21/890.5870
- Federal Register, final order 2026-07366, “Physical Medicine Devices; Reclassification of Non-Invasive Bone Growth Stimulators”, 16 April 2026: https://www.federalregister.gov/documents/2026/04/16/2026-07366/physical-medicine-devices-reclassification-of-non-invasive-bone-growth-stimulators
- openFDA device classification, product code LOF: https://api.fda.gov/device/classification.json?search=product_code:LOF
