Do Thinx and Saalt use the same absorbency labels?

No. Thinx publishes 3 current tiers (100 mL across the range) and Saalt publishes 4 (10–50 mL). Even where the words overlap, the millilitres differ, which is exactly why this page compares them in millilitres with a data-quality grade on every number.

How do Thinx and Saalt sizes compare?

Thinx runs true to size; Saalt runs true to size. Both size from your hip measurement, so the size finder gives your size in each brand directly rather than guessing from the other brand's number.

Thinx vs. Saalt

How Thinx and Saalt period underwear compare on the only thing that travels across brands - capacity in millilitres - plus how each one's sizing runs. No brand's thumb on the scale.

Updated 2026-06-12 · Every capacity is the brand's own claim, graded and dated

By their own published claims, Thinx reaches a higher maximum capacity (up to 100 mL) than Saalt (up to 50 mL) at its highest current tier. That does not make every Thinx pair more absorbent than every Saalt pair - it means the top of Thinx's range is higher. Compare tier by tier in millilitres, not by the label words.

Absorbency tiers, side by side

Thinx

See Thinx

Tier	Capacity	Grade
All Day	100 mL	Data quality grade A, brand publishes mL
All Night	100 mL	Data quality grade B, converted from tampon counts
Overnight (Teens)	100 mL	Data quality grade B, converted from tampon counts

Verified against Thinx's own pages 2026-06-11

Saalt

See Saalt

Tier	Capacity	Grade
Light	10 mL	Data quality grade B, converted from tampon counts
Regular	15 mL	Data quality grade B, converted from tampon counts
Heavy	20 mL	Data quality grade B, converted from tampon counts
Super	40–50 mL	Data quality grade B, converted from tampon counts

Verified against Saalt's own pages 2026-06-11

Claims, not lab measurements

Every capacity above is the brand's own maximum claim, typically from a saline saturation test. The only published study with real blood components (BMJ Sexual & Reproductive Health, 2023) measured period underwear holding about 1 to 3 mL before leaking - far below these maximums. Use the numbers to compare the two brands like for like, not as a leak-free guarantee.

Sizing

Thinx runs true to size; Saalt runs true to size. Both brands size from your hip measurement, so rather than converting one brand's size into the other's, the size finder gives you your size in each directly.

Thinx: Runs true to size. Thinx states styles are "completely true to size" and recommends following the HIP measurement (measured at widest point, derriere included) for the most accurat

Saalt: No explicit runs-small/large statement on the main Saalt Wear size chart page; waist is "measured at your belly button" and hips "measured around the widest part of your hips." Bra

Quick answers

Is Thinx or Saalt more absorbent?: By their own published claims, Thinx reaches a higher maximum capacity (up to 100 mL) than Saalt (up to 50 mL) at its highest current tier. That does not make every Thinx pair more absorbent than every Saalt pair - it means the top of Thinx's range is higher. Compare tier by tier in millilitres, not by the label words. And remember these are saline-lab maximums, not leak-free guarantees - the only blood-component study measured far lower real capacity.
Do Thinx and Saalt use the same absorbency labels?: No. Thinx publishes 3 current tiers (100 mL across the range) and Saalt publishes 4 (10–50 mL). Even where the words overlap, the millilitres differ, which is exactly why this page compares them in millilitres with a data-quality grade on every number.
How do Thinx and Saalt sizes compare?: Thinx runs true to size; Saalt runs true to size. Both size from your hip measurement, so the size finder gives your size in each brand directly rather than guessing from the other brand's number.

Skip the comparison - get your answer

Tell the translator your flow and it gives the covering tier at both Thinx and Saalt. Tell the size finder your hip and it gives your size in each.

What absorbency do I need?Find my size