Class IV Laser Therapy: What It Is, What It Feels Like, and Who It Helps

Class IV laser therapy is a treatment where a handheld device shines focused red and near-infrared light onto a sore or injured area. There are no needles, no incisions, and nothing to recover from afterward.

The goal isn't to numb pain for an afternoon. It's to give the tissue under the skin a little more of what it needs to calm inflammation and repair itself, so it pairs naturally with the adjustments and rehab work that address why the area got irritated in the first place.

Most people who ask us about it want to know three things: how light can possibly help, whether it hurts, and whether it actually works. We'll take those one at a time.

Lasers are sorted into safety classes by how much power they put out. Class IV is the highest, covering lasers over 500 milliwatts. The lower-power devices you may have heard called "cold lasers" sit in the classes below it.

In a treatment setting, that extra power is the point. Researchers describe Class IV therapy as reaching deeper into tissue and delivering a useful dose in less time than low-power lasers, which matters for areas like the low back or hip where the irritated tissue isn't right under the skin.

It's also why safety basics aren't optional. A Class IV beam is a hazard to the eyes, even from a reflection, and enough of it in one spot can be a hazard to skin. That's what the eye protection and the constantly moving handpiece are for.

The evidence for laser therapy is encouraging in some areas and thin in others, so here's what it actually shows.

Neck pain has some of the better support. A 2009 review in The Lancet pooled 16 randomized trials with 820 patients and found low-level laser therapy reduced pain right after treatment in acute neck pain, and in chronic neck pain, with relief lasting up to 22 weeks after treatment in follow-up. Side effects were mild and no different from placebo.

For low back pain the picture is more mixed. The American College of Physicians' 2017 guideline lists low-level laser therapy among the non-drug options for chronic low back pain. An older (2008) Cochrane review, though, concluded there wasn't enough consistent data to draw firm conclusions, and found laser plus exercise wasn't clearly better than exercise alone.

For high-powered (Class IV) lasers specifically, a 2023 review of randomized trials across musculoskeletal problems found less pain and better function compared with control treatments, with only one adverse reaction reported (though many of the trials didn't report side effects at all). The authors rated the evidence low quality for pain and moderate for function and asked readers to treat it with caution. That's why we use laser as one part of a plan, never as the whole plan.

We don't use laser as a stand-alone fix. It's usually added to a plan that's already addressing the structure behind the problem, whether that's chiropractic adjustments, structural rehabilitation, traction, or physiotherapy. Laser supports the healing; the rest of the plan works on what's causing the irritation.

Before your first session, Dr. Johns reviews your history to make sure laser is appropriate for you. If it isn't a good fit for what's going on, he'll tell you so plainly. If you're dealing with pain that's been slow to calm down and want to know whether laser makes sense, give us a call at 941-933-1500.