Unders By Proof Vs. Thinx Period Underwear: In-depth Differences

Period underwear are reusable underwear designed to absorb menstrual flow, serving as an alternative or backup to pads and tampons. Two popular brands in the category are Thinx and Proof.

Here is an overview of their key features and differences:

AspectsUnders by ProofThinx
AbsorbencySuper absorbent with 4 layers of protectionModerate absorbency with 2-3 layers
Size RangeXXS-4XLXXS-4XL
Style VarietyHipster, bikini, thongHipster, hi-waist, thong, boyshort
Price$24-36 per pair$24-38 per pair
Warranty1 yearNone

Overview of Unders by Proof

Unders by Proof launched in 2020 and has quickly grown in popularity for its highly absorbent period panties. Their collection includes three absorbency levels – Lighter Days, Medium Flow and Heavy Flow.

The core features and benefits of Proof underwear include:

Unders By Proof Period Underwear
  • Super absorbency – Each pair contains 4 layers of protection along the gusset to hold up to 4 tampons worth of fluid. This makes them among the most absorbent options on the market.
  • Innovative protection – Proof uses patented airlux technology and quick-drying materials to pull moisture away from the skin, preventing leaks, odor and discomfort.
  • Extended sizing – Proof offers an inclusive range from XXS to 4XL to accommodate most body types.
  • Stylish and seamless – The underwear features a seamless design and comes in thong, bikini and hipster styles in both prints and solids.
  • 1 year warranty – Proof stands behind their products with a 1 year warranty if any issues arise.

Overview of Thinx

Founded in 2014, Thinx were one of the first companies to offer period panties direct-to-consumer. They use absorbent, multi-layer technology and offer three main absorbency levels:

  • Light absorption for spotting
  • Moderate absorption for light flow
  • Super absorption for heavy flow

Key benefits of Thinx period underwear include:

  • Moisture-wicking fabric – The inner layer pulls moisture away and allows more airflow.
  • Antimicrobial treatment – The gusset contains an antimicrobial treatment to prevent odor.
  • Stylish options – Thinx offers several silhouettes like boyshorts, thongs, high waist and more.
  • Eco-friendly materials – Products use sustainable textiles like organic cotton.

Comparison of Absorbency and Leak Protection

Thinx Period Underwear
Thinx Period Underwear

One of the biggest differences between the two brands is their absorbency power and effectiveness at preventing leaks.

Thinx advertises 2-3 layers of protection and holds about 1-2 tampons worth of fluid.

The lighter options work well for spotting and light days but some customers report issues with leakage during heavy flow.

By comparison, Unders by Proof contains 4 layers of fabric engineered to distribute fluid evenly across the gusset.

The Heavy Flow style in particular can hold nearly 4 tampons worth of fluid.

Several reviews mention Proof as the “most absorbent period underwear” especially on heavy days with few leaks. The peace of mind of less leakage is a major pro for Proof.

For those with a very heavy cycle, Unders by Proof may provide better protection while Thinx offers adequate absorbency for lighter needs.

Comfort and Fit Comparison

Proof scores high marks for comfort with its patented airlux fabric that keeps wearers dry by pulling moisture away from the skin. The gusset is also free of harsh chemicals and contains probiotics for healthy pH balance.

However, a few reviewers found the extra absorbent layers of Proof to be overly bulky, especially when wet. Thinx offers a slimmer construction that lays flatter under clothes.

In terms of sizing, both brands cater to a wide range from XXS to 4XL. Proof underwear may run slightly small while Thinx has more generous sizing. Try each brand’s fit finder quiz to find the best match.

Those with sensitive skin may prefer Proof’s organic cotton materials while moisture-wicking modal works well for staying dry.

For convenience, Proof packs also allow building a custom cycle-specific set. Thinx offers more color and style variety for those who prioritize aesthetics.

Care and Maintenance

Both Proof and Thinx provide similar care instructions to get the longest wear out of pairs:

Thinx Period Panties
  • Cold water wash and air dry
  • Avoid fabric softener or dryer sheets
  • Use a laundry bag for delicates

One advantage of Proof is that the absorbent layers stands up well to repeated washing without losing effectiveness.

Thinx may be more prone to pilling or damage over time.

Proof also offers a 1 year warranty against defects while Thinx does not have a formal guarantee.

Proof’s excellent customer service makes exchange and returns hassle-free.

Pricing and Value

Proof and Thinx price points are similar ranging from $24 – $36 per pair depending on the absorbency and style. Considering the reusable nature and quality construction, both present good value replacing hundreds of disposable products.

Those needing max absorption may find Proof offers better value with around $1/use over a 2 year lifespan. While pricier upfront, this shakes out to pennies per wear making them very cost-effective long-term.

Thinx frequent sales and rewards program helps offset costs especially for lighter needs. Their diverse inventory also caters well for building a full cycle-wardrobe.

On the whole, Proof ranks as the better bang-for-buck in terms of absorbency while Thinx takes the lead on affordability for lighter flows.

Social Responsibility

An important factor for many customers today is social responsibility. Both brands focus sustainability efforts in this area:

  • Thinx partners with organizations that promote menstrual equity and access while Proof donates underwear and supports women’s health initiatives.
  • Products use Oekotex certified textiles free of harmful chemicals. Thinx also contains recycled materials in their fabric blends.
  • Compared to single-use disposables, reusable underwear reduces waste sent to landfills.
Thinx Period Underwear

In the past, Thinx faced controversy over issues like inconsistent sizing, quality declines and lack of maternity leave for staff.

However the brand has made strides to improve transparency and production oversight after the turmoil.

Meanwhile Proof is a newer company that so far has an excellent track record for corporate responsibility and positive workplace culture.

But being a younger brand, they have less history to go on.

Overall if ethics are a priority, both Thinx and Proof aim to empower women through sustainable businesses – though values may evolve as each continues maturing.

Summary: Key Differences

ProofThinx
Greatest absorbency and leak protectionMore affordable for lighter flows
Airlux fabric keeps wearers dryVariety of styles and prints
1 year warranty plus excellent serviceEstablished brand with strong community
Ideal for heavy periodsBetter for spotting to medium flow

Frequently Asked Questions (FAQ)

Why not to buy Thinx?

There are a few reasons why some shoppers may prefer other brands over Thinx:
Inconsistent sizing/quality – Thinx has faced criticism over declining quality and fits that don’t match size charts. This makes ordering tricky.
Discomfort/sweat – A few wearers notice moisture-trapping with Thinx leading to chafing or irritation. Those prone to this may do better with ultra-breathable options.
Lack of warranty – No formal guarantee means you’re responsible if pairs wear our prematurely.
Ethical issues – Past controversies around work culture and lack of maternity leave tarnished their reputation in some consumers’ eyes.
However, Thinx still appeals to many thanks to cute styles, frequent sales and brand recognition. As a pioneer in the category, they will likely continue popularizing reusable options regardless of past growing pains.

What is the Thinx controversy?

In 2017, a story emerged accusing Thinx of promoting a toxic, exploitative work environment that clashed with their feminist branding. Employees faced low pay, nonexistent healthcare stipends and no maternity leave while upper management emotionally abused staff.
The controversy highlighted hypocrisy and sparked discussion around “performative activism” in startups claiming social responsibility. However, in the following years leadership changed hands along with revamped policies to address these issues. Thinx now actively works to course-correct past wrongs through corporate transparency and accountability.

Is Knix the same as Thinx?

Knix is another established reusable underwear brand that competes with Thinx. While they share similarities, key differences include:
Absorbency – Knix offers up to 3 layers of protection for light to moderate flow needs. Thinx specializes more in heavy absorption.
Sizing – Knix pairs run small and may not work for plus sizes. Thinx fits more true-to-size.
Styles – Knix focuses on basics and neutrals where Thinx has colorful prints and trend-forward silhouettes.
Price – Knix costs more per pair compared to Thinx’s frequent discounts. But Knix often has bundle packs that enhance value.
So in summary – Knix and Thinx overlap in the period panty space but have unique strengths based on absorption, fit, selection and pricing.

Can Thinx hold pee?

While not marketed as incontinence underwear, Thinx can provide backup leakage protection for minor bladder leaks. Their absorbent gusset and moisture-wicking fabric handle small urine accidents well.
However, Thinx aren’t overnight diaper replacements for frequent heavy urinary incontinence. Those with regular leakage or overflow issues still need products designed specifically for bladder control.
In a pinch, Thinx make excellent backup on light leakage days or for short term sneeze/cough dribbles. But they lack overnight capacity and breathability for chronic, heavy incontinence needs. Look to brands like Modibodi, Knix or Depend for fuller urine absorption.

Closing Remarks

In the reusable underwear space, Proof is the leader in absorbency and high-tech performance while Thinx offers affordability and style variety. Deciding between them depends most on your flow levels and personal priorities.

Both modernize periods with sustainable innovation so women can feel comfortable and empowered every day of the month. Reusable underwear provides freedom from single-use disposables – making Proof and Thinx game-changing brands.

Clayton S. Johnson

Well, I am Clayton who writes, manages, and does overall stuff for this website. I live somewhere in Stone Mountain, Georgia, and used to have a full-time job. But the pandemic taught me to do more do with my life. So, I quit my job and travel a lot! Since I have tons of time now, I write about all the stuff I have done, used, and have first-hand experiences.

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