Laundry detergents come in a variety of forms, including liquids, powders, pods, and sheets. Along with differing in how convenient they are to use, these types vary in cleaning features and strengths. Here’s an overview:
Liquids
The most popular form of laundry detergent, liquid detergents can be measured exactly and their doses are easily adjustable. Liquids work well in all water temperatures, including cold (which we used exclusively in our testing). Liquid laundry detergent is an especially good choice for oil- or grease-based stains; a liquid formula can penetrate oily stains (and fabric) better than a powder paste can.
Most liquid detergents contain stain-busting enzymes, though some do not. Often labeled as “wash” or “laundry soap,” nonenzymatic detergents rely primarily on surfactants and are similar to castile or other oil-based soaps. We’ve found that although they clean fine in warm water, they don’t clean as effectively in cold water as enzymatic detergents do, and they can leave soap scum and other residues in the machine.
Powders
Powder detergents are made primarily of the same ingredients as liquid detergents, and they tend to clean soil-based stains like mud, clay, and peat better than liquids. In our testing, powder detergents also tackled stains from tannins (red wine, tea) and other natural pigments (beta-carotene, turmeric, grass) effectively. This is likely because powder detergents often contain sodium percarbonate—the main ingredient in OxiClean—which is delivered most effectively in powder form and rarely found in liquid detergents. (A liquid solution will hit a point where no additional sodium percarbonate can dissolve, chemical engineer Tre Wright explained, thus limiting the amount it can contain. None of our liquid picks have sodium percarbonate.)
Powders can be a challenge to dispense neatly. They don’t always dissolve well in cold water, but some newer powders (such as our top pick) are designed to dissolve rapidly and completely. Powder detergent is sometimes considered to be harsher on fabrics, causing dyes to fade more easily. But according to fabric care experts, color fading in laundry washed with powder detergent is likely due to residue from using too much detergent.
Pods
Laundry pods (also called unit doses, packs, discs, or tablets) typically contain a single dose of liquid laundry detergent encased in a water-soluble polyvinyl-alcohol (PVA/PVOH) film. Some pods contain separate chambers of additional stain- or odor-fighting boosters, which combine with the main detergent when the pod’s casing dissolves in water.
Although the Environmental Protection Agency (EPA) includes PVA/PVOH on its Safer Chemical Ingredients List and the Environmental Working Group (EWG) recommends cosmetic and cleaning products that contain PVA/PVOH, some are wary of its environmental impact. PVA/PVOH is technically biodegradable, but it takes time to fully break down, and extensive research isn’t available on its long-term biodegradation.
Pods are convenient and low mess, taking most of the guesswork out of dosing detergent. They are light and easy to carry, which could be helpful for those with limited mobility or strength, or people who tote their wash to a laundromat or shared laundry room. You can’t accidentally pour too much detergent into your machine with a pod. But you can’t pretreat or precisely adjust your dose per load, and they are typically more expensive, which is why we generally prefer liquid and powder formulas. Responsible storage of pods (and all detergents) is also an important consideration in order to help prevent accidental ingestion and poisoning, particularly for those living in households with children or people living with dementia.
Sheets
Sheet detergents are relatively new. While they are sometimes advertised as a so-called plastic-free alternative to laundry detergent pods, they use the same petroleum-based PVA/PVOH that encases pods. Few detergent sheets contain enzymes; four of the five brands we tested do not. The sheets we tested were all terrible cleaners, and they don’t offer any advantage—environmental or convenient—over pods.
We tested more than 35 laundry detergents. You can read our full testing protocol.
Here’s how we evaluated them:
Formulas and ingredients: For this guide we looked at high-efficiency (HE), enzymatic (sometimes called bio-based) detergents. (We also tested a few detergents that do not contain enzymes.) We paid close attention to ingredients lists and made note of possible irritants, including fragrances, dyes, and a few specific preservatives that some people may be sensitive to.
Stain removal: We looked for detergents that clean a wide variety of stains effectively. Using a detergent that eradicates stains means you may not have to pretreat mild-to-medium stains or pretreat and rewash heavy stains, ultimately saving time and energy (and, hopefully, your favorite shirt).
Cold water performance: The majority of energy used by a washing machine occurs during hot water cycles. Washing clothes in cold water saves energy and is ultimately one of the most environmentally impactful things you can do in the laundry room. (Research also suggests that using cold water might reduce microfiber and microplastic waste from your clothes, though the science is not settled.) We tested every detergent using cold water, evaluating how each dissolved and checking the washer drum and dispenser for residue. All of our picks remove stains and odors in cold water well and leave no residue.
Odor removal: We washed T-shirts stained with bacon grease with each detergent and had volunteers smell and rank them after they dried.
Scent: Whether or not you want a scented detergent comes down to personal preference. In general, we favored unscented or mildly scented options.
Availability: While we tested a few more niche laundry detergents, we looked for detergents with widespread availability.
There’s no industry-wide stain standard for detergent testing, but we took cues from the guidelines established by ASTM International, a global standards development organization, for making stains and evaluating them. We test each detergent using specialized test strips (stained with more than a dozen substances, including red wine, pig blood, sebum, peat, and engine oil). We also stain T-shirts with two sets of identical stains, including grass, coffee, tea, and motor oil (which helps test odor removal). We wash the strips and T-shirts with a full load of laundry in a cold water wash, eliminating low-performing detergents after each round.
