What Is Modal Fabric? Is It Good for Undershirts?

Getting dressed shouldn’t feel like a strategic exercise. Yet for many women—especially professionals, commuters, and anyone moving through long, unpredictable days—comfort, sweat, and fabric performance quietly shape how confident we feel in our clothes.

If you’ve come across modal fabric while shopping for undershirts or base layers, you might be wondering: What exactly is it? And more importantly, is it actually good for everyday wear?

The short answer: yes. The longer, more useful answer is below.

TL;DR

Modal is a plant-based, semi-synthetic fabric made from beech tree pulp. It’s known for its softness, breathability, moisture management, and durability—making it one of the best fabrics for women’s undershirts and everyday base layers.

What Is Modal Fabric?

Modal is a type of rayon made from natural cellulose, most commonly sourced from beech trees. While “modal” is often used as a general fabric term, Modal™ is also a trademarked fiber, most notably produced by Lenzing AG. Over time, the name has become synonymous with a certain standard of softness and performance.

You’ll often hear modal described as “artificial silk.” Not because it’s delicate—but because it’s smooth, fluid, and comfortable against the skin while remaining far more durable and practical for daily wear.

How Is Modal Fabric Made?

Modal begins in sustainably harvested beech trees. Here’s the simplified journey from forest to fabric:

1. Harvesting & pulping – Beech trees are turned into wood chips, then processed to extract cellulose.

2. Cellulose treatment – The cellulose is treated with a low-impact chemical process (less intensive than traditional viscose).

3. Spinning into fibers – The solution is spun into fine fibers.

4. Woven or knit into fabric – Those fibers become yarn, then fabric.

Because modal fibers are smoother and more uniform than cotton, the final fabric feels softer, lighter, and more refined—without sacrificing strength.

Key Features of Modal Fabric

Modal has become a go-to fabric for elevated basics because it quietly solves many everyday clothing frustrations.

• Softness that lasts: Modal fibers are finer and more uniform than cotton, creating a smooth, silky feel that doesn’t roughen with washing.

• Breathable and thermoregulating: Modal allows air to circulate and helps regulate body temperature, making it comfortable across seasons and environments.

• Moisture-managing: Instead of holding sweat in one place, modal absorbs moisture and distributes it across the fabric so it can evaporate more efficiently.

• Durable and resilient: It resists shrinking, fading, and pilling—important for garments worn and washed frequently.

• More sustainable by design:

• Made from renewable beech trees

• Requires significantly less water than cotton

• Often produced in closed-loop systems

• Biodegradable under the right conditions

Pros and Cons of Modal Fabric

No fabric is perfect. What matters is whether its strengths align with how you actually wear it.

What’s the Goodside of Modal Fabric?

• Exceptionally soft and smooth

• Lightweight and breathable

• Manages moisture better than cotton

• Holds shape and color over time

• Lays flat and invisible under clothing

What’s the Downside of Modal Fabric?

• Slightly higher cost than basic cotton

• Can wrinkle more than synthetic fabrics

• Performance depends on how it’s blended and constructed

For undershirts and base layers, modal’s advantages typically outweigh its limitations.

Common Uses for Modal Fabric

Because of its balance of comfort and performance, modal is widely used in:

• T-shirts and everyday tops

• Loungewear and sleepwear

• Activewear blends

• Underwear and undershirts

• Bedding and towels

Anywhere softness, breathability, and durability matter, modal tends to perform well.

Modal vs. Other Fabrics

Choosing an undershirt fabric isn’t about finding the “best” fabric overall—it’s about choosing the one that supports long days, real movement, and layered outfits.

Modal vs. Cotton

Modal vs. Polyester

Modal vs. Silk

Why Modal Works So Well for Undershirts

Think about bras for a moment. Most women don’t own just one—they choose different styles depending on outfits, weather, and mood. Undershirts work the same way.

A true undershirt is not a camisole. Camisoles are sleeveless and don’t protect the underarm area, where sweat is most visible. An undershirt needs to do quiet, practical work while staying invisible.

Modal excels as a base layer because it:

• Feels like a second skin

• Breathes through long workdays and commutes

• Helps manage moisture without bulk

• Moves with the body rather than clinging

For women who layer under blouses, sweaters, and blazers, modal creates comfort without compromise.

How to Care for Modal Fabric

Modal is designed for real life.

• Machine wash cold

• Use a gentle detergent

• Tumble dry low or lay flat

• Avoid bleach and high heat

With proper care, modal maintains its softness, shape, and color over time.

How Numi Uses Modal (and Why Women Trust It)

Our modal undershirts transform the way you get dressed—and quietly protect the clothes you love most. Slip one on and move through your day without second-guessing sweat, comfort, or polish. Each piece is sumptuously soft, thoughtfully engineered to keep you feeling fresh, comfortable, and confident from morning commute to evening plans.

Our modal undershirts are made with:

• 90% Modal™ for softness, breathability, and temperature regulation

• 10% Lycra® for stretch, recovery, and a smooth, close-to-the-body fit

• Built-in 100% Pima cotton underarm sweat shields for targeted sweat and odor protection

Together, these elements form a fabric system. Modal keeps you comfortable, Lycra ensures the fit stays put, and Pima cotton sweat shields absorb moisture and block it from reaching your outer layers—without bulk or stiffness.

The result is an undershirt that women describe as:

• Comfortable enough to forget

• Effective enough to trust

• Polished enough to wear under everything

It’s not about fixing a problem loudly. It’s about supporting women quietly, where it matters most.

Curious about what really matters in undershirt fabrics? Explore All You Need to Know About Undershirt Fabrics or see how materials compare in our Top 7 Sweat-Absorbing Undershirt Fabrics.

Key Takeaways

• Modal is a plant-based, semi-synthetic fabric made from beech trees

• It’s softer, lighter, and more breathable than cotton

• Modal manages moisture better for all-day comfort

• Blended with Lycra®, it’s ideal for undershirts and base layers

• Thoughtful construction matters as much as fabric choice

Final Thoughts: A Better Modal Base Layer Starts Underneath

When the layer closest to your body works well, everything else feels easier. Clothes last longer. Outfits feel more comfortable. And you move through your day with quiet confidence.

Modal plays a meaningful role in that experience. When paired with thoughtful construction—like stretch for fit and targeted underarm protection—it becomes more than a soft fabric. It becomes a dependable foundation you can trust, day after day.

Ready to start with a better modal base layer? Explore our Numi modal undershirt essentials for everyday layering—designed to keep women comfortable, confident, and cared for all year round.

When you’re ready, save 20% on your first order with code JOINNUMI at checkout. No rush — it’ll be waiting for you when the time feels right.

FAQs about Modal Fabrics

Is modal better than cotton?

Modal and cotton serve different needs, but for undershirts and base layers, modal often performs better. It’s softer, lighter, and manages moisture more evenly than cotton, which tends to stay wet once saturated. Modal also resists shrinking and lays flatter under clothing, making it more comfortable for all-day wear.

What is the downside of modal fabric?

The main downside of modal is cost—it’s typically more expensive than basic cotton. Modal can also wrinkle more easily than synthetic fabrics. That said, when modal is thoughtfully blended and well-constructed, its comfort, durability, and performance usually outweigh these tradeoffs.

Is modal as bad as polyester?

No. Modal and polyester are very different. Modal is plant-based and breathable, while polyester is petroleum-based and can trap heat and odor. Polyester may be more wrinkle-resistant, but modal offers a softer feel, better airflow, and a more natural wearing experience—especially for garments worn close to the skin.

Can you put modal fabric in the dryer?

Yes, modal can be tumble-dried on low heat. To preserve softness and shape, it’s best to wash in cold water and avoid high heat. Gentle care helps modal garments last longer and maintain their smooth drape.

Is modal too hot for summer?

No. Modal is lightweight, breathable, and naturally temperature-regulating, which makes it comfortable even in warm weather. It allows air to circulate and helps moisture evaporate, so fabric doesn’t feel heavy or clingy. For summer, modal works especially well in lightweight blends and thoughtfully designed base layers that sit close to the body without trapping heat.