To find the perfect fit, measure the waist and hips, then compare them to our sizing chart. The full sizing guide is available on each product page. When between sizes, going with the larger option usually offers a more comfortable fit.

These are designed to fit true to size. Select the usual size based on the waist measurement guide. No need to size up or down unless a looser or tighter feel is personally preferred.

Our fit is designed to follow the body’s natural shape — supportive without compression, and flexible enough for all-day wear. The fabric offers gentle stretch for movement while maintaining its form over time.

Yes. Our underwear is made with Bamboo Lyocell, which is naturally hypoallergenic, ultra-soft, and free from harsh chemicals often found in conventional fabrics. Its smooth, breathable fibers are gentle on sensitive skin and help reduce irritation, making it an ideal choice for those with common fabric allergies.

• Machine wash on a gentle cycle using cold or warm water (up to 40°C).
• Use a mild detergent
• Avoid bleach and fabric softeners
• Tumble dry on low or hang to dry
• Do not iron

No, our high-quality fabric is exceptionally durable and retains its shape and fit far better than cotton or other traditional fabrics, even after numerous washes. Its superior stretch and resilience ensure long lasting comfort, structure, and performance.

Yes. Our Bamboo Lyocell is naturally breathable and thermoregulating. Its moisture-wicking properties help maintain a cool, dry feel in warm conditions and provide gentle insulation when it’s cooler—promoting daily comfort.

Yes. Bamboo Lyocell's softness, breathability, and stretch make it ideal for everyday wear, sleep, and workouts. It moves with the body while maintaining support and comfort across different activities.

Global sperm counts have dropped by over 50% in the last 50 years, and 1 in 6 couples now face infertility. This isn’t just a personal issue — it’s a public health crisis. Environmental threats like endocrine-disrupting chemicals (EDCs), heat exposure, and poor lifestyle habits quietly damage reproductive health every day. Fertility is no longer guaranteed by age or gender — it must be protected proactively, starting with what touches the body for hours daily.

Our underwear is engineered to support reproductive wellness from the ground up. The core fabric, Bamboo Lyocell, is naturally breathable, moisture-wicking, and hypoallergenic. It helps regulate temperature and reduce heat buildup, which is critical for protecting fertility. Unlike conventional underwear, it contains no harmful toxins or endocrine-disrupting chemicals (EDCs), minimizing daily exposure to invisible risks that affect hormone balance and reproductive function.

While no underwear can guarantee conception, Mr. Fertyl is designed to support conditions that promote reproductive health. By regulating heat, reducing exposure to toxins, and minimizing friction and moisture buildup, the underwear helps create a more fertility-friendly environment. Every detail — from fabric selection to construction — is optimized for those who care about protecting hormonal balance and long-term reproductive wellness.

Our underwear is ideal for anyone looking to reduce exposure to hormone-disrupting chemicals, manage heat around the reproductive area, or support long-term hormonal health. Whether trying to conceive now or simply planning for the future, making intentional choices with daily essentials can make a meaningful difference — especially for those with fertility concerns, endocrine sensitivities, or a proactive approach to wellness.

Mr. Fertyl underwear is made from Bamboo Lyocell — a fabric chosen specifically to eliminate direct skin contact with synthetic fibers. Bamboo Lyocell is naturally hypoallergenic, OEKO-TEX® certified, and produced using a closed-loop process that avoids toxic solvents. It’s breathable, temperature-regulating, and free from harmful finishes, dyes, and endocrine-disrupting chemicals (EDCs) — all critical factors when protecting reproductive health.

Yes. A well-known Harvard study involving 656 men found that those who wore looser-fitting underwear had 25% higher sperm concentration and 17% higher total sperm count compared to those who wore tighter styles. The men in tighter underwear also showed elevated levels of follicle-stimulating hormone (FSH), a marker linked to impaired testicular function.

The study highlights how heat retention and restricted airflow from conventional underwear can negatively impact male fertility. Mr. Fertyl was created in direct response to this research — using breathable, heat-regulating Bamboo Lyocell to minimize these risks and protect reproductive health.

Source: PubMed: 30102388

Fertility is declining at a global level, yet most clothing brands ignore the role everyday materials play in reproductive health. Mr. Fertyl was created to fill that gap — to offer underwear engineered specifically for fertility protection.

Rather than following trends or focusing purely on comfort or price, the focus was placed on eliminating hidden risks: endocrine-disrupting chemicals, poor breathability, and heat-retaining fabrics. Every design detail — from the Bamboo Lyocell fabric to the fully-covered waistband — exists to support hormonal balance and reproductive wellness.

We are not just another underwear brand. We are the the first brand built around fertility as a priority — not an afterthought.

Mr. Fertyl is built on sustainability at every stage — from raw materials to end product. Each pair is made with closed-loop Bamboo Lyocell, a fabric that recovers 99% of water and non-toxic solvents during production, drastically reducing waste. Materials are responsibly sourced, manufacturing is optimized for low impact, and all packaging is designed to be minimal, recyclable, and plastic-free. The goal: zero compromise on health or the planet.

Conventional cotton is one of the most resource-intensive crops in the world. It requires around 2,700 liters of water to produce a single cotton T-shirt and accounts for 16% of global insecticide use, contributing to soil degradation, water pollution, and deforestation. Even organic cotton, while free from synthetic pesticides, still consumes large amounts of water and requires significant land use.

Bamboo Lyocell offers a cleaner alternative. It’s produced in a closed-loop system that recycles 99% of water and solvents, drastically reducing water usage and chemical waste. The bamboo used is fast-growing, requires no fertilizers or irrigation, and thrives without pesticides. The result: a fabric with a significantly lower environmental footprint—without compromising on softness, comfort, or safety.

Bamboo Lyocell delivers real environmental benefits across the board:

• Requires far less water than cotton, with 99% of it recycled in a closed-loop system.
  
• The manufacturing process is low-energy and designed to reduce carbon output.
  
• Grown without pesticides or fertilizers, preserving biodiversity and preventing runoff.
  
• Uses natural solvents and captures nearly all input materials during production.
  
• Bamboo grows rapidly without replanting or deforestation.
  

Choosing Bamboo Lyocell isn’t just better for the planet — it’s a smarter, cleaner fabric that aligns comfort & health with long-term sustainability.

Yes, Bamboo Lyocell is one of the safest fabrics in the world for both the body and the planet. It's made using non-toxic solvents in a closed-loop system that prevents chemical runoff into the environment. Unlike conventional fabrics, it contains no harmful residues, is OEKO-TEX certified, and is naturally hypoallergenic. The result is a fabric that’s gentle on skin, safe for sensitive areas, and produced with minimal environmental impact.

Waste reduction is built into every step of the process:

• Bamboo is grown without pesticides, fertilizers, or irrigation — eliminating agricultural runoff and preserving soil health.
  
• 99% of water and solvents are captured and reused, minimizing chemical waste and emissions.
  
• Manufacturing processes are optimized to reduce energy consumption and material loss.
  

The goal: deliver high-performance underwear with minimal environmental footprint — from factory to end product.

Mr. Fertyl underwear is made from ultra-soft Bamboo Lyocell, a naturally smooth fiber that feels cool, light, and barely noticeable on the skin. The fabric’s fine structure eliminates friction, while its advanced breathability and moisture-wicking properties help regulate temperature throughout the day. A fully covered elastic waistband delivers a secure fit without chafing or pressure points, ensuring all-day comfort whether sitting, sleeping, or on the move.

Bamboo Lyocell is highly breathable by design. Its microstructure allows for continuous airflow, helping heat and humidity escape quickly. During warm weather or physical activity, the fabric naturally regulates temperature while pulling moisture away from the body to keep skin dry and irritation-free—without relying on synthetic performance coatings.

Every element is designed to deliver a refined wearing experience. The Bamboo Lyocell fabric offers a silk-like softness with a natural sheen. A smooth, tag-free interior and carefully finished edges create a clean, elevated feel. The fully wrapped waistband adds a final touch of understated luxury, combining form and function in one minimalist silhouette.

Yes. The fabric’s smooth, hypoallergenic surface reduces friction, making it ideal for extended wear. Bamboo Lyocell naturally resists odor, wicks moisture, and regulates temperature—minimizing sweat, chafing, and skin irritation. No exposed elastics or synthetic tags touch the skin, ensuring lasting comfort from morning to night.

Yes. Bamboo Lyocell maintains its softness even after repeated washes due to its long, smooth fibers. The fabric resists pilling, and the fully enclosed waistband prevents stretching or warping. With proper care, both the texture and fit remain consistent over time—without sagging, stiffening, or losing elasticity.

Orders typically ship within 1-2 business days. Delivery times depend on your location and selected shipping method, with most U.S. orders arriving within 2-8 business days.

Yes. A tracking number is emailed as soon as the order ships. Tracking can be used to monitor delivery progress in real time. Please be sure to check spam or promotions folders if the email isn’t visible.

Orders are processed quickly, so changes or cancellations must be requested within 1 hour of purchase. Contact support immediately, and the team will do their best to assist before the order ships.

Once an order has shipped, changes or cancellations are no longer possible.

Yes. Free standard shipping is available on U.S. orders over $120. Expedited shipping options may be offered at checkout for an additional fee.

Not at this time, but international shipping is coming soon. Sign up for updates to be the first to know when global delivery becomes available.

If a package is delayed or missing beyond the estimated delivery window, contact support immediately for assistance. Our team will coordinate with the carrier to locate the shipment or issue a resolution as quickly as possible.

Multipacks are eligible for return within 30 days if unworn, unwashed, and in original packaging. For exchanges, contact support for help finding the right fit.

To initiate a self-serve return, please log in to your customer account:

Click Here To Access Your Account Portal.