Trusted by 150,000+ Men

1 Free Pack

1 Free Pack

check_circle Zero plastic, Zero Toxins against your skin

check_circle Supports your hormonal health and fertility

check_circle Long leg cut, No chafing, No riding-up

check_circle 365-Day Wear Guarantee

Low Stock • Ships today if ordered within 20m 45s
  • 365-Wear Guarantee
  • FREE SHIPPING OVER $60
  • Free Returns & Exchanges

SHIPPING

How fast will I receive my order?
Standard US shipping: 1–7 business days. You'll receive a tracking number as soon as your order ships.

Is shipping free?
Free shipping on all orders above $60.

WARRANTY

The 365-Wear Guarantee
Wear them every day for a year. If they ride up, fade, lose shape, or let you down in any way — we replace them or refund you. You keep the boxer either way.

No forms. No hoops. No questions asked.

Fabric: 95% OEKO-TEX Certified Organic Cotton, 5% BPA/PVC-Free Elastane (Exclusive of Waistband)

Dyes: Non-toxic and OEKO-TEX® certified, safe for your skin and everything below the belt.

Care: Cold wash, tumble dry low. Some shrinkage is normal, size up for the perfect post-wash fit.

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Trusted by Experts

Recommended by athletes, doctors, entrepreneurs & health professionals

Cal Verano, Pro Triathlete
Cal Verano Pro Triathlete, Endurance Coach
★★★★★

“I train in heat for a living, so I pay attention to what traps it and what doesn’t. Synthetic underwear is the worst offender and nobody talks about it. These are the first pair I’ve worn that actually breathe on a long ride.”

Cal Verano

Pro Triathlete, Endurance Coach

Devon Marsh, Men’s Health Coach
Devon Marsh Men’s Health Coach
★★★★★

“I have guys dialing in sleep, training, bloodwork, supplements. Then they go and wear plastic against their skin 24 hours a day. It’s the cheapest variable on the list and the one nobody touches. This is the first thing I tell them to change.”

Devon Marsh

Men’s Health Coach

Dr. Elias Kovan, MD, Urologist
Dr. Elias Kovan, MD Urologist
★★★★★

“The research on heat and endocrine-disrupting chemicals at the contact layer has been building for 30 years. Underwear is the one exposure a man controls completely. Choosing a natural fiber is a reasonable decision, and it costs almost nothing.”

Dr. Elias Kovan, MD

Urologist

Ethan Vail, Founder
Ethan Vail Founder, Health Entrepreneur
★★★★★

“I spent two years removing plastic from my kitchen, my water, my food storage. Then I realized I was still wearing it for sixteen hours a day. Switching took one order. It’s the easiest change I’ve ever made for that kind of payoff.”

Ethan Vail

Founder, Health Entrepreneur

What nobody told you about your underwear.

What you're wearing is working against you. Every single day.

  • MICROPLASTICS

    That boxer you've worn for years? It's shedding microscopic plastic particles directly against your most absorbent skin — 24 hours a day. Polyester is melted plastic. Every movement, every wash, every hour releases microplastics into your body. You just didn't know.

  • TOXIC DYES & FINISHES

    Daily chemical exposure at your most hormone-sensitive skin. BPA and phthalates mimic and block hormones — lowering testosterone, disrupting reproductive health. Most underwear brands use cheap synthetic dyes. Nobody reads the label.

  • SWAMP ASS

    You're adjusting before lunch. That sticky, humid feeling that follows you everywhere. Polyester traps heat, blocks airflow, and turns your underwear into an overheated environment where bacteria thrive. Heat also accelerates chemical release from synthetic fabric — making everything worse at once.

  • CHAFING

    That redness at the end of the day isn't normal. It's not your skin, it's not your body type — it's friction from a boxer that was never built for how you're actually built. A 3-inch inseam bunches between your thighs the moment you move. Great Build's flat seams and 7–8 inch long leg cut eliminate the contact point entirely. No bunching. No friction. No chafing.

  • CONSTANT RIDING UP

    You've adjusted in public more times than you can count. You assumed that was just how it is — your thighs, your body type, your problem. It's not. Standard boxer briefs have a 3–4 inch inseam. The moment you move, the fabric has nowhere to go but up.
    What you're wearing is working against you. Every single day.

    Backed by science

    100%

    Of testicules tested contains microplastics.

    97%

    Chance that wearing polyester boxers will lead to lower fertility.

    90%

    Of customers says that they stop adjusting their boxer during the day.

    NIH Studies.

    365 DAY WEAR GUARANTEE

    Zero risk

    Wear them for a full year, risk free.

    Free shipping. Free returns and exchanges.

    Great Build VS others

    See how Great Build is important for you.

      Others
    Support Fertility, Hormonal Health
    Breatheable Material
    All-Day Fit
    OEKO-TEX Certification
    Microplastic Shedding
    365-Days Warranty

    FAQs

    Most customers notice a difference within 1-2 weeks.

    Wear them every day for a year. If they ride up, fade, lose shape, or let you down in any way — we replace them or refund you. You keep the boxer either way. No forms. No hoops. No questions asked.

    Size up if you're between sizes. Great Build fits true to waist but the priority is the thigh — if you're built bigger through the legs, go up one size for the right fit. Some shrinkage is normal after the first wash, so sizing up gives you the perfect post-wash fit.

    Standard US shipping: 1–7 business days. Free shipping for order above $40. You'll receive a tracking number as soon as your order ships.

    That's exactly who Great Build was built for. Athletic fit, extra room through the thighs, long leg cut. Wear them through a full day — commute, meetings, errands — and you won't adjust once.

    Two things no other brand combines: a long leg cut engineered for thicker thighs, and fabric that contains zero plastic, zero toxins. Most "comfortable" boxers are still 80–90% polyester. Ours aren't.

    Most men's underwear is 80–95% polyester — a fabric made from melted plastic. It releases microplastics, BPA, and phthalates directly against your most sensitive skin, 24 hours a day. These are endocrine disruptors — chemicals that interfere with hormone production. Your underwear is the one thing touching your body every single hour. It matters what it's made of.

    It's real. Four peer-reviewed studies published on the NIH database confirm it:

    Microplastics released during washing of polyester fabrics
    → pmc.ncbi.nlm.nih.gov/articles/PMC9000408/

    Endocrine disrupting effects of micro and nano plastics
    → pmc.ncbi.nlm.nih.gov/articles/PMC9885170/

    Microplastics: A Threat for Male Fertility — testosterone & sperm quality
    → pmc.ncbi.nlm.nih.gov/articles/PMC7967748/

    Microplastics exposure: implications for human fertility and pregnancy
    → pmc.ncbi.nlm.nih.gov/articles/PMC10794604/

    We didn't build Great Build on a trend. We built it on this.

    Contact us within 365 days. We make it right. That's the guarantee.