Baking Soda vs Activated Carbon
Arm and Hammer and Fresh Step attack the same problem, litter box odor, with two different tools. Arm and Hammer uses baking soda, a natural mineral that neutralizes acids and bases in odors. Fresh Step uses activated carbon, a highly porous material that traps odor molecules. Both are effective, but baking soda is the simpler chemistry. In one study, an odour-eliminating spray in litter boxes reduced behaviour that signals a cat is unhappy with its box. That study tested a spray, not a litter.[1] Evidence: limited
The difference shows up in the bag. Arm and Hammer litter has a visible baking soda core in each granule, and the Clump and Seal line is designed to seal odor inside the clump. Fresh Step is more focused on tight clumping and carbon-based odor control, with scent options that many owners either love or avoid.
Before you weigh odour claims against each other, note that the evidence on scent is thin. In a multi-cat study, cats preferred a clean box to a dirty one, but the odour of urine or faeces alone did not change their preference; physical and visual obstructions mattered more.[2] Evidence: limited We did not find a controlled study of perfumed litter. For more on what cats prefer, see what cats actually prefer.
Clumping and Odor Compared
| Aspect | Arm & Hammer Clump & Seal | Fresh Step |
|---|---|---|
| Clump quality | Very tight, seals odor in | Tight and firm |
| Odor control | Excellent, baking soda core | Excellent, activated carbon |
| Dust | Low | Low |
| Unscented options | Good | Excellent |
| Signature | Baking soda in every granule | Activated carbon, scent variety |
Arm and Hammer Clump and Seal produces clumps so tight they practically form a solid seal around waste, which is where the brand's odor control comes from. Fresh Step clumps are also firm, and its activated carbon handles ammonia well. For pure odor neutralization, especially in a warm room or a small apartment, Arm and Hammer has a slight edge.
Where Each One Wins
Both litters are sold in several bag sizes, so check the current size and price on the Amazon listing before you buy.
Both brands have multi-cat formulas and unscented options, but the strengths differ. Arm and Hammer gives you the strongest odor neutralization. Fresh Step gives you the best clumping and the strongest unscented lineup.
The Best Bags Compared
Arm & Hammer Clump & Seal Platinum Multi-Cat Litter
The flagship Arm and Hammer formula and the strongest odor neutralizer in this comparison. Each granule has a baking soda core, and the Clump and Seal design locks odor inside the clump. Owner reviews consistently praise how long the box stays fresh between changes.
- Baking soda in every granule
- Seals odor inside the clump
- Strong multi-cat performance
- Clumps can be sticky when wet
- Some formulas are scented
Fresh Step Advanced Simply Unscented Clumping Litter
Fresh Step's unscented formula and the safest pick for scent-sensitive cats. It clumps hard, controls ammonia with activated carbon, and has no perfume at all. If your cat refuses scented litter, this is the high-performance choice.
- Truly unscented
- Excellent clumping
- Strong ammonia control
- Low dust
- Heavier bag
Fresh Step Clean Paws Multi-Cat Litter
Fresh Step's all-round multi-cat formula. It clumps hard, controls odor with activated carbon, and the Clean Paws design tracks less. A dependable choice for homes with two or more cats that want Fresh Step's clumping quality.
- Tight, firm clumps
- Activated carbon odor control
- Low tracking
- Strong multi-cat performance
- Scent may not suit all cats
If you are weighing litter types, our clumping vs non-clumping guide covers the trade-offs, and the cat litter guide compares these brands with wood, silica, and natural alternatives.
Which Litter Should You Choose
Choose Arm & Hammer if odor control is your top priority, or if you like the simplicity of baking soda chemistry. Clump and Seal is one of the best odor-fighting litters you can buy.
Choose Fresh Step if you want the tightest clumps, a genuinely excellent unscented formula, or the low-tracking Clean Paws line.
For the food side, our guides to best cat food for indoor cats and best cat food for senior cats go through that side.
How to Switch Litters Safely
Switching litters is often painless, but some cats may be sensitive to a change in texture or scent. Mix the new litter into the old gradually over several days, starting with a small share of new litter and increasing it each day. If your cat is picky, keep an unscented formula in the mix, because scent is one possible reason a cat refuses a litter.
One practical note: both brands sell scented and unscented versions, and some owners find the scented versions cause more trouble. If you are switching and your cat hesitates, move to the unscented formula before giving up on the brand.
What Owners Report
Arm and Hammer owners consistently report that the Clump and Seal line keeps odor under control for longer than other litters they have tried, which is the brand's core promise and the reason it has such a loyal following. The most common negative is that the clumps can be sticky if the litter is poured too deep, so shallow filling is the trick.
Fresh Step owners split between the scented and unscented camps. The scented fans love the fresh smell, while the unscented fans praise the Simply Unscented formula for controlling ammonia without perfume. Both groups agree on the clumping, which is tight and dependable. Between the two brands, Arm and Hammer wins on odor neutralization, and Fresh Step wins on unscented performance.
Frequently Asked Questions
Arm & Hammer Clump and Seal is the stronger odor neutralizer, thanks to its baking soda core that seals odor inside the clump. Fresh Step is also excellent with activated carbon, but Arm & Hammer is the most consistent for pure odor control.
Yes. The Clump and Seal line produces very tight clumps that are designed to seal odor in. Some owners note the clumps can be sticky if the box is overfilled, but in normal use the clumping is excellent.
Both brands are sold in several bag sizes and both have multi-cat formulas and unscented options. Check the current bag size and price on the Amazon listing before you buy.
Fresh Step Advanced Simply Unscented is the best unscented option of the two, with no perfume at all. Arm & Hammer also makes unscented formulas, but Fresh Step's unscented clumping is the stronger all-round pick.
You can, but it is usually better to pick one and stick with it, because cats can be sensitive to sudden litter changes. If you want to switch, transition gradually by mixing the two litters over a week.
The Bottom Line
Arm and Hammer and Fresh Step are both excellent clumping litters with different strengths. Arm and Hammer has the best baking-soda-based odor neutralization. Fresh Step has the tightest clumps and the best unscented formula.
If odor control is your biggest problem, Arm and Hammer Clump and Seal is the answer. If you want the cleanest scoop and a truly unscented high-performance litter, Fresh Step is the one to get.
See Arm & Hammer on AmazonSick of scooping every single day?
Neither of these litters solves the scooping, only the smell between scoops. If the daily scoop is the part you actually want gone, the automatic box guide compares the machines.
Best Automatic & Self-Cleaning Litter Boxes →Willemijn has kept animals for around 45 years. She did not have these particular items in her own home. What follows is her read on them, put together from research and from what she has seen at other owners' houses. We keep it separate from her hands-on notes on purpose, because the two are not the same thing.
Arm & Hammer Clump & Seal Platinum. Clumps perfectly, no dust, and it smells pleasant. Drawback: Slightly dearer.
Fresh Step Clean Paws Multi-Cat. Clumps well, but the scent is strong. Drawback: The added scent is too strong.
Fresh Step Advanced Simply Unscented. Clumps well, no smell. Drawback: The clumping is not perfect.
Willemijn is a friend of the founder and is not paid for this.