Why we Wear Rash Guards

Why Every BJJ Practitioner Should Be Training in a Rash Guard (With or Without the Gi)

Whether you’re rolling in the gi or training no-gi, one piece of gear deserves a permanent spot in your BJJ rotation: the rash guard. Once seen as a no-gi essential, rash guards are now becoming more and more common under the gi — and for good reason. More than just a stylish layer, a quality rash guard improves hygiene, comfort, and performance on the mats.

Training With the Gi: Why Wear a Rash Guard Underneath?

Wearing a rash guard under your gi may not be required in all schools or competitions, but the benefits are undeniable:

1. Hygiene and Skin Protection
   Let’s face it — BJJ is an up-close-and-personal sport. A rash guard creates a barrier between your skin and the gi, reducing direct exposure to sweat, bacteria, and mat-borne germs. This extra layer can help reduce the risk of ringworm, staph, and other common skin infections that can sideline your training.

2. Comfort and Reduced Friction
   Gi fabric can be rough on the skin, especially after long rolls. Rash guards reduce chafing under the armpits, around the neck, and across the torso, making training sessions more comfortable and less irritating — literally.

3. Regulating Body Temperature
   Moisture-wicking rash guards help keep you cool when you’re hot and warm when you’re cold. By managing sweat more efficiently, they prevent that clammy feeling and help maintain performance over longer sessions.

4. Compression Benefits
   Compression from a snug rash guard can aid circulation, muscle support, and recovery. While it’s not a miracle cure for soreness, it does offer subtle benefits during intense training blocks.

No-Gi? A Rash Guard is Mandatory — and Here’s Why

In no-gi training and competition, rash guards are more than a smart choice — they’re often mandatory.

1. Required for Competition
   In IBJJF-sanctioned no-gi events, competitors must wear a rash guard that meets specific criteria (more on that below). Not having one that complies could disqualify you before you step on the mat.

2. Performance and Durability
   Rash guards offer muscle support and minimize scrapes from rough mats and accidental scratches from fingernails or gear. They also hold up better than standard athletic shirts, meaning they can take the beating that regular training delivers.

3. Improved Grip Control
   Rash guards reduce excessive grip by making it harder for opponents to latch onto your torso or arms — something you definitely want in a sport where every inch counts.

IBJJF Rules: What You Need to Know About Rash Guards

If you plan to compete under IBJJF rules in no-gi, rash guard compliance is essential. Here's what they require:

• Color and Design: Your rash guard must display at least 10% of your rank color (blue, purple, brown, or black) or be fully colored to match your belt rank.

• Fit: Rash guards must be form-fitting. Loose or baggy tops are not allowed.

• Sleeves: Both short and long sleeves are permitted, but no sleeveless options are allowed.

• Logos/Designs: Logos and designs are allowed, but they should not obscure the visibility of your rank color.

If you show up without a proper ranked rash guard, you might not even get the chance to compete. Don’t leave it to chance — be prepared, and do it in style.