Comparing Period Underwear: Knix VS Thinx
UPDATED: APRIL 2024
I LOVE talking about all things period - and I've been pretty open about my own period routine. If you've been keeping up with the blog, you know that I switched to a menstrual cup over 2 years ago and have been loving it. But lately, there's been tons of talk about period underwear. I'm a member of a variety of women's groups and there's always questions popping up asking if period underwear are worth it, which brand to get, etc.
Because I want to continue minimizing my carbon footprint, be part of the conversation, and help women make a well-informed purchase - I bought a pair of period underwear from Knix and a pair from Thinx.
knix underwear review, thinx underwear review
Knix Review
Cost: $39.55 (for 1 pair with tax & shipping)
Construction: Seamless, absorbant gusset
Performance: Great for medium - light days
Knix is a Toronto-based company, that sells bras, underwear and previously loungewear. I have purchased one of their bras in the past, as well as regular underwear which is made from nylon and Lycra and is seamless.
Their leakproof line is designed for periods and some underwear can hold up to 3-5 super tampons-worth of fluid, which is roughly 35-60mL.
While the underwear can hold quite a bit if fluid, I pair my Knix with my DivaCup. As of 2024 this is what my routine looks like:
Leakproof high rise —> These are my daytime choice, especially while working. I feel like my body has changed since both pregnancies, and the high rise just keeps everything ‘in.’
bikini —> These are my at-home/back up
dream shorts —> Overnight holy grail. I may never need to use hydrogen peroxide again (IYKYK). If you’re going to get any one of these products - this is the one. Do it for your bedsheets.
Their leakproof underwear is designed very similarly to their regular line - both are seamless, the body is made from nylon and Lycra, the only difference is that the leakproof pair has a lined crotch (also known as a gusset), which is 86% cotton. Since buying my first pair, the gusset has changed and covers a wider area - especially with the Dream Shorts, making me more at ease during those heavy days.
Caring for them is simple, I toss them in an undergarment bag and pair them with like colours. After washing, I toss the bag into the dryer.
2021 UPDATE: I used the dream shorts during my postpartum period - specifically the few weeks after my cesarean birth. I found the shorts to be quite comfortable, as they didn’t aggravate or rub against my scar. I lined the shorts with a Natracare maternity pad (the shorts acted as my insurance policy).
I recommend buying a pair of these for the postpartum - regardless of the type of birth you’re planning on having. It’s a nice sustainable alternative to underwear like Depends and Frida Mom underwear (which is also great, but are disposable).
2023 UPDATE: I’m going through the postpartum period again, and recovering from a vaginal birth. The shorts were a staple and I used them with the Natracare pads (again), as well as the Frida Mom ice pads. Once my period returned (a bit heavier than usual), the shorts remained my #1 for protection at night.
2024 UPDATE: I don’t think I’d give up my leakproof Knix underwear at this point. They’ve become essential to my period routine.
(Feel free to use my code: dr.alexsiapriolo.nd-tryknix for 15% a minimum spend of $120)
Thinx Review
Cost: $43.97 (for 1 pair with discount and shipping)
Construction: Not seamless, fully lined, extra layer from front of the gusset extending to the back
Performance: Great for heavy days and overnight
Thinx is an American-based company that only sells period-proof underwear - although they do have a sister company called Speax designed for women who experience urinary incontinence. Thinx is moisture-wicking, anti-microbial, absorbent and leakproof. My pair is made with breathable PUL fabric, and the inside layer is 95% cotton (which is great for those who suffer from chronic vaginal infections). I purchased the scarlet hiphuggers, that are designed to hold 2 tampons worth of fluid. Like Knix, they have various styles (like boy shorts) that hold different amounts of liquid.
These are fully lined and feel heavier than Knix. I wore these during my heavier days, including overnight. They felt very snug and secure, adding to that extra sense of overnight security. When I did notice some slight leakage during the day and night, the Thinx absorbed everything and did not stain any clothes or sheets! Taking care of the Thinx was also rather simple. After I finished using them, I rinsed them in water, machine washed in cold water and tossed them in the dryer. They do advise to hang them to dry, but I've stopped doing that.
2 MONTH UPDATE: The threads of the band have started to get a bit loose and pull at the top. For a product that costs more than $50, this is really disappointing. I don't believe that all pairs have this band, so it may not affect the other pairs. However you may want to make this consideration if purchasing the hiphuggers.
6 MONTH UPDATE: No other threads have come loose. Aside from that minor issue 4 months ago, everything has remained the same.
2019 UPDATE: I have 2 pairs of the Thinx now, the last pair I got on sale for about $32.00 Canadian. If you can get them on sale, I would recommend it for heavier days.
2020 UPDATE: A recent report has come out indicating a discovery of chemicals in the gusset of the underwear: "polyfluoroalkyl substances (PFAS) on the inside layers of the crotch. These are chemicals known to be toxic to humans, even at very low levels, and have been linked to cancer and fertility problems." The original report is linked here - where the author sent in a pair of unwashed Thinx and Lunapads to be tested for chemicals.
Since then, Thinx has published a blog post about their products being body safe and have stated: "The truth is that US regulations aren’t as strict as those in the EU, which is why we comply with both US regulations and the EU’s REACH regulations. For example, while the US has banned 11 chemicals from cosmetics, REACH bans 1,328. By complying with REACH, we’re also supporting REACH pre-market testing requirements — all to protect our customers’ safety and wellbeing."
2023 UPDATE: I don’t wear my Thinx products anymore, mostly because my size changed and I wasn’t inclined to repurchase since all my other underwear are Knix.
2024 UPDATE: I saw these at my local Real Canadian Superstore! I didn’t purchase them (I have so many Knix at this point), but it was nice to see that are more accessible in Canada.
knix underwear review, thinx underwear review
Final Thoughts
2024 UPDATE: Originally I felt like this was a pricey experiment. Nowadays I’ve collected a few pairs (some were gifted in exchange for Instagram posts) and I have good routine going with my cup. I haven’t purchased tampons in 7 years, and I’ve only used pads for a few postpartum periods.
Because of the heavier postpartum periods, I’m so thrilled that I haven’t washed my sheets in a panic. Work is also a breeze on my heavy flow days.
Out of all the products I have (and I have many after about 7 years), if you’re going to start with one pair - may I recommend the Dream Short. Knix often has mid-year sales, so keep an eye out for those if you’re interested in trying a pair!
I mentioned this earlier in the post, but feel free to use my code: dr.alexsiapriolo.nd-tryknix for 15% a minimum spend of $120.