When I first started looking for the ultimate comfort and a more sustainable choice in my daily essentials, the world of men’s underwear felt a bit overwhelming. But I quickly found that focusing on 100% organic cotton men’s underwear really simplifies things and brings a ton of benefits. You’re not just choosing comfort. you’re also making a stand for your health and the planet. This isn’t about fleeting fashion trends. it’s about making an informed decision for something you wear every single day, right against your most sensitive skin.

To really elevate your underwear game, you should prioritize 100 percent organic cotton that’s certified by trusted organizations. This guide is going to walk you through everything you need to know, from why organic cotton is a must to the top brands offering amazing options like best 100 percent cotton briefs men, best 100 percent cotton boxers men’s, and the ever-popular boxer brief best 100 percent cotton men’s underwear. We’ll even explore the difference between 100 cotton vs 95 cotton underwear and give you some pro tips on how to care for your new favorites so they last. So, let’s get you set up with some seriously good undies that feel great and align with your values.

If you’re ready to upgrade right now, here are a few top picks you can check out:

Table of Contents

Why Go 100% Organic Cotton for Your Underwear?

Let’s be real, your underwear is the first thing you put on in the morning and the last thing you take off at night. It’s in constant contact with some of your body’s most sensitive areas. So, doesn’t it make sense to choose a fabric that’s truly beneficial? Switching to men’s 100 organic cotton underwear isn’t just a trend. it’s a smart move for comfort, health, and the environment.

Superior Breathability and Moisture Management

One of the biggest wins with 100 percent cotton men’s underwear is its incredible breathability. Unlike synthetic fabrics like polyester or nylon that can trap heat and moisture, cotton’s natural fibers allow air to circulate freely. This means you stay cooler and drier throughout the day, which is a huge deal for preventing discomfort, chafing, and even issues like yeast infections or bacterial growth in warmer climates. Think about it: that constant airflow helps wick away sweat naturally, keeping things fresh down there.

Hypoallergenic and Gentle on Sensitive Skin

If you’ve ever dealt with skin irritation, rashes, or allergies from your underwear, 100% organic cotton might be your savior. Conventional cotton is often treated with a cocktail of harsh chemicals – pesticides, herbicides, toxic dyes, formaldehyde, heavy metals, and even flame retardants. Residues from these chemicals can linger in the fabric and cause allergic reactions or irritation, especially for people with sensitive skin or conditions like eczema. Organic cotton, on the other hand, is grown without these harmful substances, making it naturally hypoallergenic and much gentler against your skin. It’s just pure, clean comfort.

Durability and Longevity You Can Count On

While some might think natural fibers are delicate, 100% organic cotton underwear can actually be incredibly durable. Organic cotton crops are often handpicked, which is gentler on the fibers compared to mechanical harvesting. This process preserves the fibers, leading to longer, stronger cotton strands. When cared for properly and we’ll get to that later!, these undies can stand up to repeated washes and wear, lasting longer than many conventional options. Investing in quality means less frequent replacements, which is good for your wallet and the planet.

Significant Environmental Benefits

Choosing organic cotton goes beyond personal comfort. it’s a powerful statement for environmental stewardship. Conventional cotton farming is notoriously resource-intensive and polluting. It accounts for a significant portion of the world’s insecticide and pesticide use, leading to chemical runoff that contaminates water supplies and harms ecosystems. Organic farming practices, by contrast, prohibit these toxic chemicals and genetically modified seeds. This leads to: The Best Laptops Under $1000, According to CNET (and Us!)

Reduced water usage: Organic cotton uses significantly less water than conventional cotton, sometimes up to 88% less.
Improved soil health: Practices like crop rotation and natural composting enrich the soil, making it healthier and more resilient.
Lower carbon footprint: Organic methods often result in fewer greenhouse gas emissions up to 46% less CO2e.
Safer working conditions: Farmers and communities are not exposed to hazardous chemicals.

So, when you buy a pair of organic cotton men’s underwear, you’re not just buying underwear. you’re supporting a system that’s kinder to the earth and everyone on it.

No Hidden Nasties for Your Health

It’s a sobering thought, but the chemicals used in conventional cotton production aren’t just an environmental problem. they can be a health concern too. Studies have linked exposure to these chemicals to various health conditions, including skin irritation, chronic coughing, and even cancers. Your skin is your largest organ, and it absorbs what you put on it. By opting for 100% organic cotton, you’re ensuring that the fabric closest to your body is free from petrochemicals, pesticides, and micro-plastics, promoting better overall health and peace of mind.

What to Look for in the Best 100% Organic Cotton Men’s Underwear

You’re convinced that 100% organic cotton is the way to go. But with so many options popping up, how do you pick the best pair? It’s not just about the “organic” label. there are a few key things to keep an eye out for to ensure you get top-notch quality and comfort.

Look for Trusted Certifications GOTS is Your Best Friend

This is probably the most crucial factor. The term “organic” can sometimes be a bit vague. To really be sure you’re getting the good stuff, look for certifications. The Global Organic Textile Standard GOTS is the gold standard. If a product is GOTS-certified, it means that at least 70% of the fibers are organic, and the entire supply chain – from harvesting and processing to dyeing and finishing – meets strict environmental and social criteria. This includes banning toxic bleaches, dyes, and finishes, ensuring ethical working conditions, and minimizing water and energy use. Best Motorcycle for 1000 Dollars: Your Ultimate Budget Ride Guide

Another good one to look for is Oeko-Tex Standard 100. While it doesn’t certify organic farming, it ensures that the final product is free from harmful substances and safe for human use. Many great organic brands will have both, giving you extra peace of mind.

Understand the Fit & Style That’s Right for You

Just like any underwear, organic cotton options come in various styles. What feels best for you depends on your personal preference and activities.

Briefs: Classic, minimal coverage, good support. They’re often recommended for reducing moisture buildup and allowing airflow. You can find excellent best 100 percent cotton briefs men for everyday wear. Check out options like KENT’s Breather Brief which aims for a balance between boxer and brief.
Boxers: Loose-fitting and airy, offering maximum breathability. Great for lounging or sleeping, or if you prefer a less restrictive feel. If you’re looking for the best 100 percent cotton boxers men’s, brands like Jockey though confirm organic for specific product and Pact offer comfortable woven options.
Boxer Briefs: A popular hybrid, offering the coverage of boxers with the support of briefs. They’re versatile for various activities. For the boxer brief best 100 percent cotton men’s underwear, you’ll want to pay close attention to the fabric blend if you’re aiming for pure 100% cotton without any stretch. Some brands manage to create a 100% cotton boxer brief that still holds its shape well.

For optimal comfort and health, especially in the groin area, looser styles like traditional boxers or relaxed boxer briefs are often recommended as they allow for better airflow and help reduce the risk of overheating.

Fabric Weight and Weave

The way the cotton is woven can affect its feel and how it performs. Most Reliable Motorcycle Under $5000

Jersey knit: This is what most t-shirts are made from, and it’s super soft and slightly stretchy even without elastane. It drapes well and is very comfortable for underwear.
Woven cotton: Typically used for traditional boxers, it has less stretch but offers maximum breathability due to its open weave. Think classic pajama bottoms.
Rib knit: Offers more natural stretch and a snugger fit than plain jersey, without needing additional spandex. Some 100% organic cotton rib boxers briefs are available, providing a good balance.

Waistband Comfort is Key

Nobody likes a waistband that digs in, pinches, or rolls down. Look for features like:

Fabric-covered waistbands: These are often much softer against the skin, especially if you have sensitivities, as they prevent direct contact with elastic.
No-roll or flat waistbands: Designed to stay put without bunching or twisting.
Tagless design: Those scratchy tags are the worst! Many quality organic underwear brands opt for printed labels instead.

Stitching Quality and Construction

High-quality underwear should have smooth, flat seams that won’t chafe or irritate your skin. Reinforced stitching, especially in stress areas, indicates a more durable garment that’s built to last. Take a moment to inspect the stitching – it tells you a lot about the overall craftsmanship.

Top Picks: Best 100% Organic Cotton Men’s Underwear Brands & Styles

Alright, let’s get down to the good stuff – specific brands that are doing an awesome job with men’s 100 organic cotton underwear. I’ve rounded up some of the best options, keeping comfort, sustainability, and quality in mind.

Pact: A True Organic Pioneer

When people talk about best 100 organic cotton men’s underwear, Pact often comes up first, and for good reason. They are deeply committed to sustainability. Their entire line of men’s underwear is made with GOTS certified organic cotton in Fair Trade certified factories. They’re even carbon-neutral! Pact offers a great range of styles, from boxers and boxer briefs to trunks and traditional briefs. Customers consistently rave about their softness and breathability. They won’t dig into your skin, and they stay put all day.

Finding the Best Mountain Bike Under $1000: Your Reddit-Approved Guide

Pros: Strong certifications GOTS, Fair Trade, wide range of styles, incredibly soft, breathable, good for sensitive skin, sustainable practices.
Cons: Primarily blends for boxer briefs often 5% elastane for stretch, truly 100% cotton options are mostly traditional boxers.
Great for: Everyday wear, those prioritizing comprehensive ethical and environmental certifications.

KENT: The 100% Synthetic-Free Champion

If you’re really serious about are there 100 cotton underwear options without any synthetics, even elastane, KENT is a fantastic choice. Their “Breather Brief” is made from 100% GOTS certified organic Pima cotton. This means zero plastics, micro-plastics, or phthalates. They’re designed to be hypoallergenic, naturally cooling, and even compostable at the end of their long life. The fit is described as a “perfect balance between boxer and brief,” offering snugness without being too tight, allowing things to “breathe cool and easy”.

Pros: Truly 100% organic cotton no elastane/spandex, GOTS certified, made fair trade, synthetic-free, compostable, ideal for ultra-sensitive skin.
Cons: Limited style options primarily the Breather Brief, might not offer the same “stretch” feel if you’re used to blends.
Great for: Men with extreme sensitivities, those seeking the purest, most natural, and fully compostable option, or anyone asking, “what underwear is 100 cotton?”

Cottonique: Allergy-Free Specialist

Cottonique is a brand that specifically caters to individuals with severe skin allergies or sensitivities. Their products are made with 100% chemical-free, GOTS-certified organic cotton. They take it a step further by offering options that are free from latex, synthetic fabrics, harsh dyes, and chemical treatments. They even have elastic-free options with drawstrings for those who react to elastic. Their ribbed boxer brief with a fly is designed to be snug yet comfortable, with moisture-wicking properties.

Pros: Specifically designed for allergies/sensitive skin, 100% chemical-free, GOTS certified, some elastic-free options available, excellent breathability.
Cons: More focused on functionality, style range might be narrower.
Great for: Men suffering from eczema, latex allergies, or extreme skin sensitivities, truly a solution for those asking, “are 100 cotton underwear good for allergies?”

Bhumi: Fairtrade and Super Soft

Bhumi offers super soft, breathable, non-toxic, and fairtrade GOTS certified organic cotton men’s underwear. They emphasize quality and ethical production. You can choose from various colors and styles, including trunks and briefs, all crafted for comfort and longevity. They are committed to creating products that support men’s wellness and don’t compromise on quality or comfort.

Pros: GOTS certified, Fairtrade, known for exceptional softness, breathable, non-toxic dyes.
Cons: Availability might vary by region.
Great for: Those looking for luxurious softness and strong ethical commitments, a great answer to “best 100 cotton underwear men’s“.

NADS: Clean and Conscious Comfort

NADS crafts underwear with health in mind, featuring GOTS certified organic cotton some of their products are 95% organic cotton and 5% BPA-free elastane, so double-check the specific product if 100% is your goal, but they do have pure organic cotton options. They emphasize being free from harsh chemicals, microplastics, and hormone-disrupting toxins, using only non-toxic OEKO-TEX certified dyes. Their boxers and briefs are designed to be soft, sweat-friendly, and durable, making them a popular choice for those wanting to protect their body from harmful substances.

Pros: GOTS certified, non-toxic dyes, focus on health benefits, soft and breathable.
Cons: Some styles may include a small percentage of elastane, so verify for 100% cotton if that’s your strict preference.
Great for: Men prioritizing non-toxic materials and comfort for active or everyday wear.

TREDECIM: Dependable Organic Basics

TREDECIM offers 100% organic cotton rib boxers briefs underwear in multi-packs, making them a practical and eco-conscious choice. Users appreciate their soft, durable fabric designed for all-day wear. They are grown without harsh chemicals, making them a healthier and environmentally friendly option. Customers often highlight their durability and minimal shrinkage when cared for properly. Unlocking Amazing Photos: Finding a Mirrorless Camera Under $300 (Yes, It’s Possible!)

Pros: 100% organic cotton, good value in multi-packs, soft, durable, eco-friendly.
Cons: Sizing can sometimes run small, so it’s wise to consider sizing up.
Great for: Those seeking comfortable, reliable, and eco-friendly basic underwear in a convenient pack.

Remember to always double-check the product descriptions for the exact material composition and certifications when buying, especially if your goal is strictly 100 percent organic cotton. Many brands offer mostly organic cotton with a small blend for stretch, which we’ll discuss next.

100% Cotton vs. 95% Cotton Underwear: What’s the Difference?

This is a question that pops up a lot when you’re looking for the best 100 percent cotton men’s underwear. You’ll often see options that are 100% cotton and others that are 95% cotton with a small percentage of something like elastane or spandex. So, 100 cotton vs 95 cotton underwear – what’s the real scoop?

The Allure of Pure 100% Cotton

As we’ve discussed, pure 100% cotton underwear offers maximum natural breathability and is the ultimate choice for sensitive skin because it’s completely free from synthetic fibers. It’s incredibly soft and allows for optimal airflow, which is essential for maintaining a healthy environment in your intimate areas. For many, the idea of having a completely natural fiber next to their skin is the most appealing aspect. If you’re looking for the purest experience, are there 100 cotton underwear options, yes, and these are your best bet.

However, 100% cotton, especially without any stretch, can have a few downsides:

Less Stretch: Without elastane, pure cotton fabrics have limited stretch. This means they might not conform to your body as snugly or offer the same range of motion that a blended fabric would.
Shape Retention: Pure cotton can sometimes lose its shape a bit over the course of a day, or after many washes, leading to a looser fit. It might also be more prone to shrinking if not cared for properly.
Absorbency: While great for wicking moisture, pure cotton can also be highly absorbent, which might not be ideal for intense workouts where you want moisture to be actively moved away from the fabric, rather than absorbed into it.

The Practicality of 95% Cotton with 5% Elastane/Spandex

You’ll find a lot of “organic cotton” underwear that’s actually 95% organic cotton and 5% elastane or spandex. This small addition of a synthetic fiber makes a noticeable difference in performance and feel. Best Lenovo Under $1000: Your Ultimate Guide to Value and Performance

Here’s why many brands and people! opt for this blend:

Enhanced Stretch and Flexibility: That 5% elastane provides just enough stretch to make the underwear move with your body, offering a better, more supportive fit without feeling restrictive. This is particularly noticeable in best 100 percent cotton boxer briefs men’s styles, where a snug fit is often desired.
Improved Shape Retention: The elastane helps the fabric bounce back, so your underwear holds its shape better throughout the day and after washing, resisting sagging and bagging.
Increased Durability: Blended fabrics can sometimes resist pilling and wear better than pure cotton, potentially extending the garment’s lifespan.
Comfort: While not 100% natural, a 95/5 blend is still incredibly soft and breathable due to the high cotton content. Many brands using this blend, especially with GOTS certified organic cotton, ensure the elastane is BPA-free and non-toxic, so you’re still getting a very healthy option.

Making Your Choice: Which is “Better”?

Ultimately, neither is strictly “better” than the other. it depends on your priorities.

If absolute purity, maximum breathability, and hypoallergenic properties are your non-negotiables, especially if you have very sensitive skin, then seeking out truly 100% organic cotton underwear men’s styles like those from KENT or Cottonique is the way to go. You might trade a little stretch for that natural feel.
If you value comfort, breathability, plus stretch, shape retention, and durability for everyday wear or moderate activity, then a high-quality 95% organic cotton, 5% elastane blend is often more practical and provides an excellent balance. Many GOTS-certified brands offer this blend, ensuring it’s still a highly sustainable and healthy choice.

When looking for what is the best 100 cotton underwear, consider what specific features matter most to you for your daily comfort and activity level.

Caring for Your Organic Cotton Underwear

You’ve made the great choice to invest in men’s 100 organic cotton underwear. Now, how do you make sure these amazing pieces last as long as possible and maintain their softness and integrity? Organic cotton, being less chemically treated, can sometimes be a bit more sensitive to harsh washing methods. But don’t worry, a little TLC goes a long way!

Wash Cool, Stay Cool Literally!

Hot water is not your friend when it comes to organic cotton. It can cause fibers to contract, leading to shrinkage and weakening the fabric and any elastic components over time. The Ultimate Guide to Finding the Best Laptop Under $1000 (Based on Reddit Recommendations for 2025)

Machine Wash: Always opt for a cold or lukewarm water cycle below 85°F is ideal on a delicate or gentle setting.
Hand Wash: If you want to be extra careful, a gentle hand wash in cold water is even better. Just fill a basin, add mild detergent, let them soak for 15-30 minutes, gently agitate, then rinse thoroughly.

Gentle Detergents are the Way to Go

Harsh chemicals can strip away natural softness and degrade the organic fibers.

Mild, Eco-Friendly Detergent: Choose a plant-based, biodegradable detergent that’s free from harsh chemicals, bleach, and strong fragrances. This is better for your undies, your skin, and the environment.
Avoid Bleach: Chlorine bleach is a big no-no. It can weaken fibers and negate all the environmental benefits of choosing organic.
Skip Fabric Softeners: Fabric softeners can leave a residue that coats the natural cotton fibers, reducing their breathability and absorbency over time.

Use a Mesh Bag for Protection

To prevent tangling, stretching, or snagging, especially if your organic cotton underwear has delicate lace or specific stitching, toss them into a mesh laundry bag before machine washing. It’s like giving them a little protective hug in the wash!

Air-Dry Like a Pro

The heat from tumble dryers is cotton’s arch-nemesis. It can cause significant shrinkage, weaken fibers, and damage any elastic in blends.

Hang or Lay Flat: The best way to dry your organic cotton underwear is to air dry them. Hang them on a line or drying rack, or lay them flat on a clean towel.
Avoid Direct Sunlight: While fresh air is great, prolonged direct sunlight can weaken fabrics and fade colors.
Low Heat if you must: If you absolutely have to use a dryer, choose the lowest heat setting and remove them while they’re still slightly damp. This helps minimize shrinkage and keeps them soft.

Smart Storage for Longevity

Once dry, give your underwear some breathing room. Avoid cramming them into an overstuffed drawer. Store them in a clean, dry space, neatly folded. This helps maintain their shape and keeps them fresh for longer. Finding Your Perfect Keystroke: Best Keyboards Under 10000

By following these simple care tips, your best 100 percent cotton briefs men, boxers, or boxer briefs will stay soft, comfortable, and supportive for years to come, making your investment truly worthwhile.

Where to Buy the Best 100% Organic Cotton Men’s Underwear

Finding quality men’s 100 organic cotton underwear used to be a bit of a treasure hunt, but these days, there are plenty of great options. The key is knowing where to look to ensure you’re getting authentic, certified products.

Online Retailers: Your Go-To for Selection

Online stores offer the widest selection and make it easy to compare brands and read reviews.

Amazon: Of course, Amazon is a powerhouse for almost everything, and organic cotton underwear is no exception. You can often find multi-packs, various styles, and brands like Pact, TREDECIM, and even some specialty options. Just be diligent about checking product descriptions for “100% organic cotton” and GOTS certifications, as well as customer reviews for fit and quality.
Brand Websites: Many of the top organic underwear brands, like Pact, KENT, Bhumi, Cottonique, and NADS, have their own dedicated websites. Buying directly from them often gives you access to their full range, detailed product information, and sometimes exclusive discounts. Plus, you’re supporting the brand directly, which is always a nice feeling.
Eco-Conscious Marketplaces: Websites specializing in sustainable or ethical fashion often curate a selection of organic cotton underwear from various brands. These platforms usually vet the brands, so you can shop with more confidence, knowing the “organic” claims are legitimate.

Department Stores and Specialty Shops

While less common for purely 100% organic cotton, some larger department stores or eco-friendly boutiques might carry a limited selection. Brands like Pact have occasionally been found in major retailers like Target, though their online presence remains the primary source for the widest organic selection. Always double-check labels for those crucial certifications if you’re shopping in person.

The Ultimate Guide to the Best Keyboards for $1000

What to Consider When Buying

Read Reviews: Customer reviews are your best friend! They can give you real-world insights into fit, comfort, durability, and whether the product lives up to its organic claims.
Check Certifications: As mentioned, always look for GOTS certification to ensure you’re getting genuinely organic and ethically produced underwear.
Sizing Charts: Underwear sizing can vary significantly between brands. Consult the brand’s specific sizing chart and, if in doubt, many suggest sizing up for comfort, especially for 100% cotton which has less stretch.
Return Policies: Especially when trying a new brand or style, check the return policy. Some companies offer a “first pair guarantee” or hassle-free returns if you’re not satisfied.

By keeping these points in mind, you’ll be well-equipped to find the best 100 organic cotton men’s underwear that meets your needs for comfort, health, and sustainability.

Frequently Asked Questions

What is the best 100 cotton underwear?

The “best” 100% cotton underwear really depends on your personal preference for style and fit, but top brands known for their GOTS-certified organic cotton include KENT especially for truly 100% synthetic-free options, Cottonique great for extreme sensitivities and elastic-free designs, and Bhumi known for softness and fair trade practices. These brands prioritize pure organic cotton and ethical production, offering excellent breathability and comfort without harsh chemicals.

Are 100 cotton underwear good?

Yes, 100% cotton underwear is generally considered very good, especially for daily wear and intimate health. They are highly breathable, which helps prevent moisture buildup and reduces the risk of irritation, chafing, and infections. For those with sensitive skin or allergies, 100% organic cotton is particularly beneficial because it’s free from the pesticides and chemicals found in conventional cotton. The main trade-off might be less stretch compared to blends, but for pure natural comfort, they’re excellent.

What underwear is 100 cotton?

Many brands offer 100% cotton underwear, but for truly 100% organic cotton, you’ll find options primarily from specialized eco-conscious brands. For instance, KENT specifically produces briefs made with 100% GOTS certified organic Pima cotton, completely free of synthetics. Cottonique also specializes in 100% chemical-free organic cotton, with some elastic-free styles. While many conventional brands like Hanes or Jockey offer “100% cotton,” it’s crucial to look for the “organic” label and GOTS certification to ensure it meets the higher standards of organic production.

Is 100% cotton underwear better for you than 95% cotton?

For skin health and purity, 100% cotton underwear can be considered better, especially for very sensitive skin, as it contains no synthetic fibers at all. It offers maximum breathability and is completely free from any potential irritants found in synthetic blends. However, 95% cotton with 5% elastane spandex offers added stretch, better shape retention, and often increased durability, which many find more practical for everyday comfort and active lifestyles. The “better” choice depends on whether your priority is absolute purity or a balance of comfort and functional stretch. Best Keyboard Under 100 Euro

Does 100 cotton underwear exist?

Yes, 100 cotton underwear absolutely exists! While many popular brands offer blends that include a small percentage of elastane for stretch, there are dedicated brands that produce genuinely 100% cotton underwear, with a strong emphasis on organic certification. Brands like KENT and Cottonique are prime examples, crafting underwear entirely from GOTS certified organic cotton, sometimes even with natural rubber waistbands or drawstrings instead of synthetic elastic to maintain pure cotton integrity.

What material is best for men’s underwear?

For general comfort, breathability, and health, 100% cotton especially organic cotton is widely considered one of the best materials for men’s underwear. It’s soft, hypoallergenic, and allows air circulation to keep you cool and dry. Other natural materials like bamboo viscose or hemp are also popular for their softness and moisture-wicking properties, often used in blends. While synthetics like modal and Tencel are also used in sustainable options for their feel and performance, for a truly natural and chemical-free experience, organic cotton often leads the pack.

Is Hanes underwear 100 cotton?

Hanes does offer men’s underwear labeled as 100% cotton, such as their ComfortSoft Men’s Cotton Boxer Brief Underwear, but it’s important to note that specific products like heathers might contain a cotton/polyester blend. While Hanes makes some organic cotton products e.g., for women, they don’t consistently highlight 100% organic cotton men’s underwear across all their 100% cotton lines in the same way specialized organic brands do. If you’re specifically looking for organic 100% cotton from Hanes, you’d need to check individual product labels very carefully for GOTS certification.

Finding the Beat: Best DJ Controller for Under $100

0.0

0.0 out of 5 stars (based on 0 reviews)

Excellent0%

Very good0%

Average0%

Poor0%

Terrible0%

There are no reviews yet. Be the first one to write one.

Amazon.com: Check Amazon for Best 100 organic
Latest Discussions & Reviews:

Best 100 organic cotton men's underwear