Sihoo M18 vs. Sihoo M59AS: Which Ergonomic Office Chair Should You Choose?

When it comes to choosing the perfect ergonomic chair, Sihoo has built a strong reputation for designing high-quality seating solutions that balance comfort, support, and durability. Among their popular models, the Sihoo M18 and Sihoo M59AS stand out as two excellent options for professionals, gamers, students, and anyone who spends long hours sitting.
At first glance, both chairs promise breathable designs, ergonomic lumbar support, and long-term durability. But they also bring different strengths to the table—one leaning toward soft comfort with traditional cushioning (Sihoo M18), while the other emphasizes advanced mesh innovation and multifunctional design (Sihoo M59AS).
In this in-depth guide, we’ll compare the Sihoo M18 vs. Sihoo M59AS across all critical categories: comfort, ergonomics, materials, adjustability, durability, design, and suitability for different users. By the end, you’ll know which chair is the right investment for your unique needs.

1. First Impressions: Core Philosophy Behind Each Chair

Sihoo M18: Balanced Comfort

The Sihoo M18 is all about soft, cushioned comfort while still keeping breathability in mind. Its signature W-shaped sponge seat ensures that your hips and thighs are supported in a natural sitting posture, while the breathable mesh back prevents overheating.
It feels more like a traditional office chair upgraded with modern ergonomics—ideal for those who still love the coziness of padding but want airflow and lumbar adjustability.

Sihoo M59AS: Advanced Mesh Innovation

The Sihoo M59AS, on the other hand, represents Sihoo’s modern, full-mesh design philosophy. With a dual-section backrest, saddle-shaped mesh seat, dynamic lumbar support, and premium airflow construction, it is engineered for precision ergonomics and long-lasting freshness.
It’s a chair that feels futuristic, offering lightness, breathability, and flexibility with almost every component being adjustable—from 3D flip-up armrests to a double-jointed headrest.

Sihoo M18 Office Chair

Sihoo M18 features a cushioned seat and breathable mesh backrest to provide a balance of soft comfort and cool airflow, even during long hours of sitting.

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2. Comfort: Cushioning vs. Mesh

Sihoo M18 Comfort

W-Shaped Seat Cushion: The sponge padding creates a plush experience, distributing weight evenly while reducing thigh fatigue.
Mesh Backrest: Keeps the back cool without losing firmness.
User Experience: Feels cozy, almost like a padded office chair, but without the heat-trapping issues of full cushions.
Best for: Users who prioritize softness under the hips and want a mix of traditional cushioning with breathable mesh support.

Sihoo M59AS Comfort

Full Mesh Seat & Backrest: Instead of foam, you sit on premium mesh that flexes to your body.
Saddle-Shaped Seat: Ergonomically distributes hip pressure, reducing discomfort during long hours.
Cooling Advantage: Even after hours of sitting, heat buildup is minimal.
Best for: Users who want light, supportive, and breathable seating with no risk of cushion flattening over time.
Verdict:
Choose M18 if you prefer softness and padding.
Choose M59AS if you want cool airflow and precise pressure distribution.

Sihoo M59AS Office Chair

The Sihoo M59AS combines a breathable mesh design with ergonomic features, ensuring comfort and support all day long.

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3. Ergonomics and Lumbar Support

Sihoo M18 Ergonomics

Dual-Adjustable Lumbar Support: Moves vertically and horizontally, allowing you to align it exactly where your lower back needs support.
Recline up to 126°: Provides a casual break mode.
Headrest Adjustability: Vertical movement plus pivot for neck alignment.
The M18’s lumbar adjustability is a huge plus for people with specific back pain points, since you can fine-tune the position both ways.

Sihoo M59AS Ergonomics

Dynamic Lumbar Support: Automatically adjusts to your movements, maintaining consistent contact with your lower back.
Dual-Section Backrest: Keeps your spine in a natural “S” curve, reducing strain on the lumbar and thoracic regions.
Double-Jointed Headrest: Offers more flexibility in neck positioning than the M18’s simpler mechanism.
The M59AS takes a more adaptive approach, meaning less manual adjustment but more consistent support throughout the day.
Verdict:
Choose M18 if you like manual control of lumbar positioning.
Choose M59AS if you want automatic adaptability and more sophisticated spinal alignment.

4. Armrests: Height vs. Full Customization

Sihoo M18

Height-Adjustable Armrests: Simple, practical, and effective for aligning with desk height.
Good for typing and casual resting but limited in angles.

Sihoo M59AS

3D Adjustable Flip-Up Armrests: Move up/down, back/forward, and rotate.
Flip-Up Feature: Useful for sliding the chair under desks or creating more space.
Verdict:
Choose M18 if height adjustment is enough.
Choose M59AS if you want full arm flexibility and space-saving practicality.

5. Recline and Relaxation

Both chairs recline up to 126°, allowing users to lean back for breaks.
M18 Recline: Pairs well with its cushioned seat, giving a cozy “lean back and relax” vibe.
M59AS Recline: Feels more weightless, thanks to the mesh support and adaptive lumbar system.
Verdict: Both excel, but the M59AS feels lighter and fresher in recline, while the M18 feels cozier.

6. Build Quality and Durability

Sihoo M18

Sturdy frame and sponge cushioning designed for long-term use.
Supports up to 330 lbs, making it slightly stronger in weight capacity.
Mesh back remains durable and easy to maintain.

Sihoo M59AS

Premium mesh construction designed for longevity without sagging.
Saddle-shaped seat resists deformation.
Built with thoughtful touches like an integrated coat hanger.
Slightly lower weight capacity than M18 but still solid for most users.
Verdict:
M18 wins for higher weight capacity.
M59AS wins for premium materials and extra convenience features.

7. Design and Aesthetic Appeal

M18 Design: Looks professional and versatile, with a more classic padded-seat vibe. Works well in both office and home setups.
M59AS Design: Sleeker, modern, and minimalistic. The all-mesh construction gives it a high-tech appeal. The integrated coat hanger adds unique practicality.
Verdict:
Choose M18 for traditional office style with comfort-first design.
Choose M59AS for a modern, tech-inspired look with functional extras.

8. Best Use Cases

Choose Sihoo M18 if you are…

Someone who values seat softness and prefers a cushioned experience.
Looking for a budget-friendly ergonomic chair with excellent lumbar adjustability.
A heavier user (supports up to 330 lbs).
A professional who wants a reliable, long-lasting office chair without too many flashy extras.

Choose Sihoo M59AS if you are…

Someone who values breathability and mesh innovation over traditional cushioning.
Spending long hours in hot or humid environments.
Wanting maximum adjustability in armrests, lumbar, and headrest.
Looking for a chair that blends modern style and advanced ergonomics.

9. Side-by-Side Comparison Table

10. Final Verdict: Which One Should You Buy?

If you’re deciding between the Sihoo M18 vs. Sihoo M59AS ergonomic office chair, the choice boils down to your personal comfort preferences and work environment.
Pick the Sihoo M18 if you want a plush, cushioned seat with high weight capacity, and you prefer hands-on lumbar adjustments. It’s the softer, cozier option that still keeps you cool.
Pick the Sihoo M59AS if you want a cutting-edge, breathable mesh chair with dynamic lumbar support and superior adjustability. It’s the cooler, sleeker, and more adaptable option, perfect for long sitting sessions in warmer climates.
Both chairs showcase Sihoo’s commitment to ergonomics and quality. Whether you choose the soft comfort of the M18 or the advanced mesh innovation of the M59AS, you’re investing in better posture, reduced fatigue, and healthier sitting habits.