How to Pick the Right Size in Period and LBL Briefs

Quick Answer

Measure your hips and waist, then match those numbers to the brand's size chart. A well-fitting period or LBL brief should sit flat against your body without digging in, and the gusset should stay in place when you move. If you are between sizes, size up for comfort and leak protection.

How to Measure Yourself for Period Underwear

Use a soft measuring tape and measure directly against your skin or over light clothing. For your hips, wrap the tape around the fullest part of your buttocks. For your waist, measure at the narrowest point above your belly button. Write both numbers down and compare them to the brand's size chart. If your measurements fall between two sizes, choose the larger size. Period underwear needs to sit close to the body to work, but it should never leave red marks or feel restrictive.

How Should Period Briefs Fit?

A period brief should feel snug but not tight. The waistband and leg openings should lie flat without cutting into your skin. When you bend, squat, or sit, the brief should move with you and the absorbent gusset should stay centered. You should be able to slide one finger under the waistband comfortably. If you can pull the brief down without unbuttoning your pants, it is likely too loose and may leak. If you feel pressure or pinching, it is too tight.

What If My Period Brief Is Too Tight?

A too-tight period brief can cause discomfort, restrict movement, and even lead to chafing. If your briefs leave deep marks or feel uncomfortable after an hour, they are too small. Check the size chart again and consider sizing up. Some brands offer different fits, like full briefs or bikini styles, which can change how the same size feels. For example, a full brief may cover more of your stomach and sit higher, while a bikini brief sits lower on the hips. If you are unsure, read the product description for fit notes. Love Luna's Super Period Full Brief has a full-coverage shape, so if you normally wear a bikini cut, you may want to check the size chart carefully.

Does the Style Affect Sizing?

Yes, the cut of the brief changes how sizing feels. A full brief offers more coverage and often sits at or above the belly button, which can feel tighter around the waist if you are between sizes. A bikini brief sits lower on the hips and may feel looser around the waist but snugger on the legs. Swim styles, like the Adult Period Swim Bikini Brief, are designed to be worn in water and may have a different fit due to the water-repellent fabric. Always check the specific product's size chart rather than assuming your usual size will work across all styles.

How to Use a Period Underwear Size Chart

A size chart lists body measurements, not garment measurements. Find your hip and waist measurements, then look for the size that includes both. If your hips and waist fall into different sizes, go with the size that matches your hip measurement for full briefs, as the hips usually determine the overall fit. For bikini styles, your hip measurement is also key. Some brands provide a size guide with a range, like S/M or L/XL. In that case, pick the range that includes your measurements. If you are at the top of a range, consider sizing up.

Can I Return Period Underwear If the Size Is Wrong?

Return policies vary by store and brand. For hygiene reasons, many retailers only accept returns on unopened, unworn period underwear in original packaging. Check the store's return policy before buying. If you are unsure about sizing, order one pair first to test the fit before committing to a multi-pack. Some brands offer satisfaction guarantees, but always read the fine print. If you cannot return, consider reselling or donating unworn pairs to local charities that accept new underwear.

Fit Checkpoints for Period and LBL Briefs

Waistband comfort

The waistband should lie flat and not leave red marks or dig into your skin. You should be able to slide one finger underneath. If it digs in, size up.

Gusset placement

The absorbent gusset should stay centered over your vaginal area when you move, bend, or sit. If it shifts, the brief may be too loose or the wrong style for your body.

Leg openings

Leg openings should sit flat against your skin without cutting in or gaping. They should not ride up when you walk. If they ride up, try a different cut or size.

Product Facts to Know

• Super Period Full Brief - Black: Super Period Full Brief - Black has a super flow absorbency of approximately 40ml (5-6 regular tampons) and features 5 layers of protection. If you have heavy flow days, this brief is designed to handle more without leaking, but you still need the right size for the layers to sit correctly against your body.
• Adult Period Swim Bikini Brief - Deep Pine: Adult Period Swim Bikini Brief - Deep Pine has 4 layers of protection and water-repellent fabric for use in water. Swim period underwear needs a snug fit to keep water out and absorbency in, so check the size chart carefully and consider sizing up if you are between sizes for comfort.
• Love Luna x Tete Garcia Period Full Brief: Love Luna x Tete Garcia Period Full Brief is a limited-edition collaboration with a full brief shape. Limited-edition styles may sell out quickly, so if you find your size, it is worth buying soon. The full brief cut offers more coverage, which can feel different from a bikini style.