Slimflex Comfort 3/4 Length Insoles – Arch Support Inserts for Plantar Fasciitis

Product Description

Slimflex Comfort - Prescribed Daily in the NHS

Clinically proven, Slimflex Insoles are prescribed daily for Plantar Fasciitis in the NHS and have several research articles backing their use in orthotic therapy. 

These arch supporting insoles also helpful for Achilles tendonitis offloading and supination. The high arch support bridges the gap between your shoe and the arch of your foot. Contoured 3/4 length insoles design allows the insole to easily fit into narrower and tighter fitting shoes.

Different from the rest, these arch support insoles were not designed for retail, but for real patients with severe foot problems. Probably the most used Foot Orthotic in the NHS today.

Best for: plantar fasciitis, arch strain, over-pronation, supination and everyday biomechanical foot support.

Not ideal for: users needing full-length cushioning or fully bespoke custom orthotics.

• Clinically established and proven orthotic design
• Heat-mouldable and fully adaptable
• Available in multiple support densities

Use timeline

First use: When first worn, Slimflex Comfort Insoles may feel firm and supportive rather than soft. This is expected, particularly for users new to structured orthoses. A short break-in period is recommended.

Short term (first few days): Mild awareness under the arch or heel is common as the foot adapts to improved alignment and support. Wear time can be gradually increased.

Ongoing use (weeks): With regular use, many users feel more comfortable when standing and walking. They also notice less fatigue in the arch and heel. Long-term comfort depends on correct density choice and appropriate footwear.

Features & Benefits

• Brush Nylon cover allows for comfort and moisture absorption. 
• Medium density to cover most pathologies.
• Integrated first metatarsal cut-out to facilitate the windlass mechanism.
• Metatarsal raise and sustanticulum tali support.
• Flat base for adhering wedging.
• Deep heel cup for greater control.
• Fully heat-moldable and grindable.
• Retail packed to dispense as supplied.

Which Slimflex Comfort Density Should You Choose?

Slimflex Comfort - Medium Density - Shore A50 Best for: Everyday use where a balance of comfort and support is needed. Typical users/conditions: General foot pain (metatarsalgia, mild plantar fasciitis, tired feet) People spending long hours standing or walking School children, teens, or adults of average bodyweight Those who want all-around support without being too soft or too firm	Slimflex Comfort - High Density - Shore A65 Best for: Active or heavier patients who need strong, long-lasting support. Typical users/conditions: Plantar fasciitis in more active or higher BMI patients Sports and high-impact activity (running, football, gym) Overpronation or biomechanical issues needing greater correction Heavy-duty or work footwear users (builders, warehouse staff, nurses on long shifts)	Slimflex Comfort - Low Density - Shore A25 Best for: Sensitive feet, lighter individuals, or those needing gentle cushioning. Typical users/conditions: Elderly patients with fragile skin or at risk of ulceration People with diabetes need extra shock absorption and reduced shear Individuals with arthritic feet, where pressure reduction is essential Low bodyweight users (<60 kg approx.)

Indications and when to use

• Slimflex Comfort are indicated for patients with plantar fasciitis, overpronation (flat feet), heel pain, metatarsalgia, Achilles tendon strain, mild biomechanical instability and general arch pain or foot fatigue.
• The insoles correct over-pronation and realign body posture to alleviate plantar fasciitis. The orthotic insoles keep your feet aligned, preventing both pronation (flat feet) and supination (foot rolling).
• Contoured ¾ orthotic insoles design allows the insole to easily fit into narrower and tighter-fitting shoes.
• Slimflex Comfort is recommended when a quick orthotic turnaround is very important. It is ideal for chairside treatment of biomechanical issues, which makes it an NHS staple today.
  
  

How does it work?

The Slimflex Comfort Insole supports the medial arch and stabilises the heel. This helps control excessive foot movement when standing and walking. The integrated first metatarsal cut-out facilitates the windlass mechanism, allowing the plantar fascia to function more efficiently during toe-off.

The contoured shape bridges the gap between the shoe and the arch, while the deep heel cup improves rearfoot control. A flat base allows for additional posting or wedging where required.

Clinical Insight

With plantar fasciitis, insufficient midfoot support allows repeated micro-strain of the plantar fascia. A contoured orthotic with adequate medial arch height and heel control comfortably reduces tensile load during stance and propulsion. Slimflex Comfort ticks all boxes.

“Orthotics should support the foot while allowing natural movement.”
Louise Fisher, Clinical Education Consultant, Algeos

Designed for Adaptions 

Some people may benefit from customised insoles made for their foot shape, walking style and condition. Modified insoles can provide personalised support and address individual biomechanical issues. 

With Slimflex Comfort, you can easily customise your treatment options in many ways. The possibilities are endless.

Heat mouldable and grindable, the Slimflex Comfort allows for quick modification and patient customisation. The flat base also allows for all posting types.

• Simple medial and lateral posts.
• Heel lift additions.
• Metatarsal raise/bar additions.
• Arch and rearfoot reinforcements.
• Shape modification.

Frequently Asked Questions (FAQs)

1. What are Slimflex Comfort Insoles?

Slimflex Comfort Insoles are medium-density, 3/4 length insoles designed to provide arch support and alleviate plantar fasciitis, Achilles tendonitis, and supination. They are commonly prescribed by the NHS.

2. How do these insoles help with plantar fasciitis?

These insoles offer good arch support. They help fill the space between your shoe and the arch of your foot. This reduces strain on the plantar fascia.

3. Are they suitable for flat feet?

Yes, the insoles are designed to support flat feet by providing the necessary arch support and correcting over-pronation.

4. Can these insoles fit into any type of shoe?

The 3/4 length design allows them to fit easily into narrower and tighter-fitting shoes.

5. Are Slimflex Comfort Insoles customisable?

Yes, they are fully heat mouldable and grindable for quick modifications and personalised fit.

6. How are these insoles different from retail options?

Slimflex Comfort Insoles are made for patients with serious foot problems. They are often prescribed in clinics, unlike many store options.

7. How do I use and maintain these insoles?

Insert the insoles into your shoes, ensuring they are positioned correctly. They can be cleaned with mild soap and water and should be air-dried.

8. Can these insoles be used for other conditions besides plantar fasciitis?

Yes, they also help with conditions like Achilles tendonitis, overpronation and supination. They assist in realigning body posture to ease different foot problems.

9. What is the material used in these insoles?

They have a soft nylon cover for comfort and to absorb moisture. The medium-density base supports most foot conditions.

10. Are these insoles suitable for sports activities?

Yes, the insoles are made to give stability and support during high-impact activities. This makes them good for sports and other physical activities. Our full-length version may be better suited for trainers/shoes with the ability to replace the insole.

11. Can I use these insoles in different pairs of shoes?

Yes, the 3/4 length design makes them flexible. You can easily move them between different shoes. This ensures you get support all day.

12. How long do these insoles typically last?

With proper care, Slimflex Comfort Insoles can last for several months. Their lifespan depends on how often you use them and your activity level.

If you have any more questions or need further assistance, feel free to contact our customer support team.

Related Pages:

View are full orthotic insoles range

View our full Plantar Fasciitis range

Written by: Algeos Product & Clinical Content Team

Last reviewed: March 2026

Purpose: This content is provided for buyer guidance and product understanding only. It is not intended as medical advice or a diagnostic tool.