Thinx Period Panties vs. Flux Undies | Comparison

Hi Ladies!

You’ve finally decided to keep a more environmentally positive life, and let go of using tampons and sanitary pads to take care of your monthly menstrual cycle. The best way to do this is by using period panties. Remember, if you also love wearing a menstrual cup, period panties can be worn in case of any leaks as well! These wonderful alternatives to tampons and sanitary pads have become extremely popular over the past decade, but which one to choose with so many out there? Here we look at two brands that are extremely popular, Thinx Period Panties and Flux Undies.

Thinx Period Panties


Thinx Period Panties can be found internationally at stores in the United States, Canada, United Kingdom, Australia, Austria, France, Iceland, Ireland, Germany, Japan, the Netherlands, South Africa, and Switzerland. They can also be bought online. The prices range from $25 to $45.


Super Hiphugger – The Super Hiphugger holds 4 regular tampons worth of blood, that’s great to use for the first day of your period. The gusset is really thick compared to the other Thinx Period Panties. This style makes you feel like you’re wearing something quite protective, where the other styles feel like you’re wearing regular underwear.

Regular Hiphugger – This has a lot of full coverage on the rear. It holds 2 regular tampons worth of blood. It’s best worn for day 2 and 3 of your period if you have a regular 7-day period.

Sport – The Sport holds 1 and a half tampons worth of blood that can be worn on day 3 onwards. It is quite a cheeky style.

Super Hi-Waist – The Super Hi-Waist holds 4 tampons worth of blood, and is for days when you’re bleeding heavily.

Highwaist – The Hi-Waist holds 2 tampons worth of blood, and is great for every day other than the heaviest day, which is usually day one. It’s great to wear with dresses, it’s really comfortable, and the stitching is stretchier on this style. 

Boyshort – These hold 2 tampons worth of blood, and are great to wear to bed.

Cheeky – The Cheeky holds 1 regular tampon worth of blood. It tends to ride up – but is called “Cheeky” for a reason.

Thong – The Thong holds half a tampon worth of blood, and is best worn on the very last day of your period, or the day just before your period begins if you experience spotting, like many women do. It’s very popular, and is great to wear even if you’re not bleeding as it’s super comfortable.

Thinx Air – The Thinx Air range is really thin, and holds 1.5 tampons worth of blood. Unlike the other styles, it’s super thin as it’s meant to dry really fast, which is nice when you’re travelling. They’re also great as they’re really stretchy and don’t cut in. They’re great to wear after the first 2 days of a heavy 7-day period. They’re available in Hiphugger and Bikini styles.

Organic Cotton – The Organic Cotton range is available in Super Cotton Brief, Cotton Brief, Cotton Bikini, and Cotton Thong styles. They hold different capacities worth of blood. These are very breathable and comfortable.

BTWN – This is for teens made with organic cotton and are in a range of fun colors and patterns. The 15-16 is the largest teen size.  They hold 3 teaspoons, or 1 and a half regular tampons, worth of blood. The gusset is also a little thicker than most the Thinx panties, excluding the Super Hiphugger which is naturally thick in the gusset as well.


Thinx is great in that they offer many color options. These colors include black, beige, maroon, blue, mauve, red, turquoise, leopard print and other fun designs. The BTWN range is especially festive in colors and patterns.


Sizes of Thinx Perod Panties are available in XXS, XS, S, M, L, XL, XXL, AND 3XL. You can refer to their size chart for exact measurements.

Flux Undies

Flux Undies was introduced to the market in 2017 in the UK. All materials used in their products are OEKO-TEX certified, which means they’re safe against the skin. They’re designed with a 3-layer fabric combination that wicks moisture, absorbs fluid and prevents leaks. They’re easily washable, and a great choice of period panties! The company gives back in the form of charity to underprivileged girls that need menstrual care.


The different styles of Flux Undies are available in an array of prices. They are available at many stores in the United Kingdom, Wales, Scotland, Northern Ireland, Ireland, and at a shop called IL-Fgura in Malta. Alternately, they are easily available online. The “heavy day” price range is as follows: The Hi-Waist costs $37, and the Classic Bikini, Boy Brief, and Detachable costs $35. The “lighter day” price range costs $32 for all styles.  The Thong costs $33.


Classic Bikini – These are offered in both heavy and light versions. The heavy version holds 4 tampons’ worth of blood and can be worn for 12 hours on heavy days, day and night. The lighter version holds 2 tampons’ worth of blood and can be worn for 8 hours on lighter days, day and night.

Hi-Waist – The Hi-Waist is also offered in both a heavy and light version. The heavy version holds up to 4 tampons’ worth of blood, and is safe to wear for 12 hours on heavier days, throughout the day and night. The lighter version holds 2 tampons worth of blood, and can easily last you 8 hours on lighter days.

Boy Brief – Again, there are 2 versions available for this particular style. The heavy version holds up to 4 tampons’ worth of blood, and can comfortably last you 12 hours for heavy days. The lighter version holds 2 tampons worth of blood, and can easily last 8 hours on lighter days.

Detachable – The Detachable is offered in both heavy and light versions. The heavy version holds up to 4 tampons’ worth of blood, and can easily be worn for 12 hours when you’re bleeding a lot. The lighter version holds 2 tampons worth of blood, and will last 8 hours comfortably before you need to change them. The Detachable version is wonderful as you can change them discreetly and easily. Thinx doesn’t offer such a version, so this style really comes out tops and is a must have for your period panty collection!

Thong – The Thong is for your lightest of days, just before and after your period when you’re spotting. They’re great to wear when you feel that your period is about to come on, but hasn’t arrived just yet.

Sizes – The sizes available are XXS, XS, S, M, L, XL, 2XL, 3XL, and 4XL. You can refer to their size chart for exact measurements!

Colors – All Flux Undies are all currently black with no other color variations which personally, I find quite boring. Although black is a great staple color and works with everything, it’s fun to have different colors to choose from. We’re women, and often choose colors to wear on our bodies depending on our moods. Compared to Thinx, when it comes to color, Flux doesn’t quite match up.

How to Decide Which Panties is the Best Choice

Sometimes there are other things that come into play when deciding which are the best period panties for you. The following are some of the things needed to be considered:

Availability & Shipment

As discussed earlier, certain shops sell both Thinx and Flux. However, there are more shops available worldwide where Thinx can be purchased. Both can be purchased online, although certain countries will cost more due to shipping costs.


Thinx Undies

Thinx Undies offers a range of different styles that hold different capacities. Their BTWN range holds 1 and a half regular tampons worth of blood. The adult styles reach a capacity capability of 4 tampons worth of blood. There are many to choose and look at.

Flux Undies

For heavy days, the Boy Brief, Classic Bikini, Hi-Waist, and Detachable holds 4 tampons worth of blood.  They also have all these in lighter versions, which all hold 2 tampons worth of menstrual fluid.  For the lightest days, there is the Thong which holds 1 pantyliner worth of blood, and is great for days when you are just spotting. 

Period Panty Sets

Thinx Saver Sets come with 2 and 3 period panties. There are 6 options to choose from. They range from $68 to $93. Flux Undies gives you more flexibility and allows you to build a set of 4 or more, while the price drops with every extra pair of period panties you buy!

Other Thinx and Flux Options

There are other superb period panties in the market today that are comparable to both Thinx and Flux. These include RubyLove Period Panties,  Lilova Period Panties, ModiBodi Period Panties and more!

Conclusion – Thinx Panties vs. Flux Undies – Which is better?

Well, all things considered there are certain pros and cons to each brand. Thinx is offered in many colors and patterns and has a teenage range. Although Flux Undies is only available in black, it has the super Detachable style which is not offered by Thinx. This makes changing on the go a whole lot easier. Thinx also offers sleep shorts, training shorts, and a leotard. Both are amazing brands with great reputations in the “Period Panties” industry. What remains is your choice at the end of the day!

Frequently Asked Questions

How do Thinx work?

Thinx Period Panties absorb your menstrual blood. Thinx is made with a patented design that is moisture-wicking, controls odor, leak-resistant, and beyond absorbent! This way you keep fresh and dry for long. They are also ultra-thin and feel like normal underwear! They also help with leaks and incontinence.

How do I wash my Flux Undies?

Flux Undies should be taken care of just like your normal underwear. You just need to rinse them after use and wait until the water runs completely translucent. You then must wash them at 30 degrees Celsius, and simply hand dry. It’s important not to tumble dry them or add any fabric softener as this will damage them.

Are Thinx free of harmful chemicals?

Definitely! All Thinx Inc. products get tested for any harmful chemicals, and are independently certified through STANDARD 100 by OEKO-TEX® which includes REACH requirements. There have never been any harmful discoveries in any of Thinx Inc. products. Everything is tested and certified. The only treatments used are moisture-wicking and anti-odor.

Can FLUX Undies replace pads and tampons?

The answer here is absolutely! The lining of FLUX undies holds up to ten times its weight, and absorbs moisture at 20 times faster than normal cotton. Because of this, Flux can absorb up to four times the amount of blood of a regular pad and can hold up to 12 long hours. You will know exactly when you need to change them!

What’s the difference between Thinx Super and Thinx Classic?

Thinx Super is great as it’s able to hold up to 4 tampons worth of menstrual blood. This is wonderful, as you don’t need to wear any “backup” products for fear of any leakage. The gusset on the Super style is a bit thicker as well. Thinx Classic period panties hold up to 2 tampons’ worth of period blood, and are perfect for medium flow days!

1 Comment
  1. When discussing underwear you should include gusset description as some women have different needs. Knowing how far back and how far forward is a very important detail.

Leave a reply