Thinx vs. The Period Company

How Thinx and The Period Company 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 The Period Company (up to 45 mL) at its highest current tier. That does not make every Thinx pair more absorbent than every The Period Company 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

TierCapacityGrade
All Day100 mLData quality grade A, brand publishes mL
All Night100 mLData quality grade B, converted from tampon counts
Overnight (Teens)100 mLData quality grade B, converted from tampon counts

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

The Period Company

See The Period Company
TierCapacityGrade
Light (Thong)10 mLData quality grade B, converted from tampon counts
Medium20 mLData quality grade B, converted from tampon counts
Heavy45 mLData quality grade B, converted from tampon counts

Verified against The Period Company'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; The Period Company 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

The Period Company: Runs true to size. Product pages state verbatim: "This style runs true to size. Order your most standard size."

Quick answers

Is Thinx or The Period Company more absorbent?
By their own published claims, Thinx reaches a higher maximum capacity (up to 100 mL) than The Period Company (up to 45 mL) at its highest current tier. That does not make every Thinx pair more absorbent than every The Period Company 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 The Period Company use the same absorbency labels?
No. Thinx publishes 3 current tiers (100 mL across the range) and The Period Company publishes 3 (10–45 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 The Period Company sizes compare?
Thinx runs true to size; The Period Company 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 The Period Company. Tell the size finder your hip and it gives your size in each.