Can Insoles Fix Plantar Fasciitis? What the Evidence Actually Says

No, insoles don't fix plantar fasciitis. They reduce the load on the fascia while everything else — rest, exercise, time, footwear — does the actual healing. That's a useful distinction. Here's why.

We sell insoles. You should know that going in. It would be convenient for us if the answer to "do insoles fix plantar fasciitis?" were yes. It isn't, and pretending otherwise would be poor medicine and poor business. The truthful version is more useful: they are a reliable supporting intervention, backed by reasonable evidence, and they are part of almost every successful conservative-care plan.

This piece lays out the trial landscape, the features that matter, and the situations where an insole won't help (so you don't waste money).

The short answer

Across the best clinical trials:

• Insoles reliably reduce pain in plantar fasciitis over 4–12 weeks, typically with small-to-moderate effect sizes [1].
• Prefabricated insoles perform roughly as well as custom-moulded orthotics in most studies, at a fraction of the cost [2].
• The mechanism is load redistribution — reducing strain on the fascia — not "correcting" foot structure.
• Insoles work best alongside stretching, loading exercises, and appropriate footwear. Used alone, their effect is modest.

What the evidence shows

The Cochrane reviews and major meta-analyses on foot orthoses for plantar fasciitis are worth reading if you enjoy that sort of thing. The headline conclusions, stripped of hedging:

1. Insoles vs. sham (a flat insert). Most RCTs show a small-to-moderate pain reduction at 8–12 weeks with active insoles vs. sham. The effect is not dramatic but it is consistent [1].
2. Insoles vs. no intervention. Insoles beat no intervention. Unsurprising.
3. Insoles vs. stretching. In head-to-head trials, stretching usually matches or slightly beats insoles at 8 weeks. Combined (stretching + insoles) beats either alone.
4. Insoles vs. injection. Corticosteroid injections relieve pain faster in the first 2–4 weeks; insoles catch up by 8–12 weeks and have no injection-related risk profile.

Translation: the insole is a useful part of the stack, on par with most other single interventions, and free of meaningful downsides. It is not a silver bullet, and no one should claim otherwise.

Prefab vs. custom — who benefits from custom

Custom-made orthotics are expensive (often £200–500). Prefab orthotics cost an order of magnitude less. The trial data is fairly clear:

• For uncomplicated plantar fasciitis, prefab insoles perform as well as custom in most studies [2].
• Custom orthotics may outperform prefab in specific structural cases: significant leg-length discrepancy, severe pes planus (flat foot) or pes cavus (high arch), rheumatoid foot deformities, diabetic neuropathy with pressure-point risk.
• If a prefab works for you after 4 weeks, there is no added benefit to upgrading to custom. If it doesn't work and a podiatrist identifies a structural issue, custom may be worth the cost.

What to look for in an insole

Not all prefab insoles are equivalent. Features that matter for plantar fasciitis:

• A supportive medial (inside) arch. The insole should actively support the arch, not just pad it. A soft foam cushion without shape is a cushion, not an insole.
• A deep heel cup. Holds the heel fat pad in place, reducing load on the fascia origin. A common feature of medical-grade prefabs.
• Appropriate density. Too soft = no support. Too firm = no comfort. A dual-density construction (firmer core with softer top) is the typical sweet spot.
• Correct length. Three-quarter length insoles work well if they end before the ball of the foot. Full-length may be better if you have forefoot symptoms too.
• Material. EVA foam, gel, and polypropylene cores all work. The specific material matters less than the shape.

This is the spec we built OrthoRelief insoles against — dual-density, deep heel cup, supportive medial arch, designed specifically for plantar-fasciitis-style heel and arch pain. We priced them at prefab cost because the evidence says, for most people, that's enough.

Where insoles don't help

The honest end of this piece — cases where an insole won't fix your problem:

• The shoe itself is the problem. An insole in a dead pair of running trainers is a wasted insole. Replace the shoe first.
• Nerve-related heel pain. If your heel pain is burning, shooting, or radiates up the leg, it may be nerve-driven, not fascia-driven, and an insole won't touch it.
• Calcaneal stress fracture. Needs offloading and imaging, not just an insole.
• You aren't doing anything else. The evidence is for insoles as part of a stack. Using them in isolation without stretching or load management will give you disappointing results.

If you haven't already, pair the insole with our home exercise programme, pay attention to what shoes you choose, and think about whether a pair of recovery slides covers the hours you spend around the house. Insoles don't fix plantar fasciitis — but alongside the rest, they reliably help the tissue get out of its own way.