In Depth Baby Product Reviews Led by a Pediatrician
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[Our review below is from 2023 when we tested the Kirkland diaper. It was a compelling product at that time. However, our review is obsolete, since at some point in 2024 Kirkland changed the product in a way that its performance severely degraded. Our review does not reflect the current product, and is invalid. We no longer recommend the Kirkland diaper. ]
REASONS TO BUY
Excellent absorption
Great leak protection
Comfortable
Durable
Inexpensive
REASONS TO AVOID
Not eco-friendly
Uses coloring/inks
It is hard to go wrong with this high-ranking traditional diaper. Not only is Kirkland Supreme above average in almost every metric, but they also eke out a high rank in our lineup of a poop-ton of contenders (pun intended). This diaper offers top performance for absorption and leak protection and still provides more consideration for health and the environment than previous Kirkland offerings. This diaper is elemental chlorine-free (ECF) and lacks lotion and fragrances. With a reasonable price lower than more well-known brands and fancy green diapers, the Signature is a diaper that appeals to most families who want affordability without sacrificing functionality. This diaper is not as eco-friendly as much of the competition. We wish there were more transparency in production and more consideration for the Earth, like being totally chlorine-free. However, we think Kirkland does what a diaper should do, does it well, and brings it all together in a durable and comfy package babies and parents will appreciate. Get the scoop on how it stands up to the competition in our review of disposable diapers.
Editor's Note: Product Change in 2024
We understand Kirkland changed the manufacturer and composition of their disposable diapers at some point in 2024. It is no longer a diaper we'd recommend to a friend. Our review below is for the previous version of the diaper. We no longer recommend the Kirkland diaper.
Our Analysis and Test Results
Costco is a wholesale, big-box retail store that owns the Kirkland brand name. This private label tries to offer quality options for a value price. The Kirkland Signature label encompasses about 20% of Costco products. The Kirkland label can be found on everything from diapers to dog food and almost everything in between.
Performance Comparison
There is much to like about the Kirkland traditional disposable diaper.
Credit: Abriah Wofford
Likes
There is so much more to like about this Kirkland option than the Supreme diaper we've tested in the past. In almost every metric, it earned points over past models, and it ended up being one of the highest-scoring disposable diapers we've ever tested.
The absorption filter paper for the Kirkland tests showed no moisture transfer indicating quick absorption of our mock urine that is locked away from the baby's skin.
Credit: Abriah Wofford
The Kirkland diaper earned a perfect score for absorption as it had almost no indication of moisture on the filter paper in testing.
Even after three rounds of tests, it continued to impress us in testing. Given the importance of absorption for the overall functionality of a diaper, these test results put it at the top of the pack.
Once absorption is complete, we use a filter test paper to see how well the diaper “locks in” the moisture to predict how much moisture is exposed to the baby's sensitive skin. Less green on the paper means less moisture on the baby's bum.
Credit: Abriah Wofford
Leak protection for the Kirkland diaper is somewhat lower than the absorption test results, but it still fared well and the likelihood of leaks under normal circumstances is limited.
Credit: Genaveve Bradshaw
Our tests and research also indicate that protection from leaks is also good for this diaper. With one of the highest scores in the group, you can feel confident that the Kirkland brand diaper is going to prevent most leaks.
If it doesn't, it was likely overdue for a change, you are using the wrong size, or no diaper could contain the nightmare blowout you now face. It happens to everyone at some point. During testing, there was some runoff in the initial pour, with the majority of the liquid pooling and quickly absorbing in the center of the diaper. Some of the drops splashed from the center and onto the outside of the absorbancy strip, and those droplets formed a small pool less than 1" wide.
The materials on the inside of the Kirkland diaper are very soft and skin-friendly.
Credit: Abriah Wofford
This diaper is a comfortable option that performed well during testing and our facility-wide survey for comfort comparison.
The main part of the diaper interior is remarkably soft compared to the competition, with testers being surprised a disposable diaper could be so soft and cloth-like. The back and legs are sufficiently stretchy with no coarseness felt and no overstretching that could cause pinches. Even the tabs are soft, with no rough edges or pokey parts.
The new Kirkland Signature diapers proved to be significantly better than the old Supreme diaper offered by Kirkland.
Credit: Abriah Wofford
Kirkland diapers don't use elemental chlorine in manufacturing, and they are free from many common irritants like lotion, natural rubber latex, and fragrance. While they could do more for considerations for the baby's health, like use no dyes or inks, they are still doing more than most traditional diapers and scored above average in this metric.
The Kirkland diaper is durable and we didn't experience any problems related to quality or durability during testing.
Credit: Abriah Wofford
Kirkland also impressed us with its design and materials creating a durable final product. We did not experience any faulty tabs or leaking SAP in our tests.
We also didn't have any problem with the back fabric breaking apart. In our online research, we also did not find many complaints related to diaper durability or quality.
The Kirkland Signature diapers have some of the highest absorbency in the group and a lower price for those on a tight budget.
Credit: Abriah Wofford
Dislikes
While Kirkland has made some significant strides to make their diaper more eco-friendly, it still isn't on par with green diapers. For a traditional diaper, it does offer more than the average option, but more can still be done. This diaper is produced using an elemental chlorine-free process. It is free of rubber latex and includes at least 23% by-weight plant-based materials. They even offer a more transparent list of ingredients on their website than we've seen in the past. So this is both a like and dislike, but given the continued need for improvement, it is hard to rave about.
The Kirkland Signature scored well in most metrics and high overall.
Credit: Abriah Wofford
Should You Buy the Kirkland Signature?
This Kirkland diaper is a departure from past Kirkland options, with far more kudos to the environment and health metrics. It has perfect absorption test results, offers a lot for leak protection capabilities, and does it all for a wallet-friendly price that is easy enough to find. We love this diaper for what it offers and that they are doing more for eco-friendliness than ever before.
What Other Disposable Diaper Should You Consider?
Kirkland makes a great diaper, but if you want something more environmentally friendly or give more consideration to health, there are better options available. Parasol Clear and Dry is a high-absorbing diaper with similar functionality to the Kirkland. Still, it offers more for being eco-friendly and considers ingredients for babies with more transparency. However, it is also expensive, with one of the highest prices in this review. If you need a more budget-friendly choice, you can split the difference with Hello Bello Premium, which has higher scores for eco and health, great absorbency, and is easy to find at a reasonable price.
