If you’re out of shampoo, several household items can clean your hair in a pinch. Conditioner, baking soda, apple cider vinegar, castile soap, and even cornstarch all work as substitutes, though each comes with trade-offs worth knowing about. Some are fine for occasional use, while others can damage your hair if they become a habit.
Conditioner (Co-Washing)
The simplest swap is washing with conditioner alone, a method known as co-washing. This works because most conditioners contain mild cleaning agents called nonionic surfactants, such as cetyl alcohol, a fatty alcohol that lifts light dirt and oil without the aggressive stripping of traditional shampoo. The cleaning power is gentle, so co-washing won’t remove heavy product buildup, but it handles everyday oil and sweat well enough.
Co-washing is especially popular with people who have curly, coarse, or dry hair, since it preserves more of the natural oils that keep those hair types soft and defined. To use it, apply a generous amount of conditioner to your scalp, massage it in for a minute or two, and rinse thoroughly. If your hair is fine or tends toward oiliness, you may find conditioner alone leaves it feeling heavy. For a one-time emergency, though, it’s the lowest-risk option in your shower.
Baking Soda
Baking soda is one of the most commonly suggested shampoo substitutes online, and it does clean effectively. It has a pH of about 9, which makes it strongly alkaline and good at cutting through grease. The problem is that your scalp sits at a pH of around 5.5, and your hair shaft is even more acidic at roughly 3.67. That gap matters.
When you apply something with a pH that high, it forces open the outer layer of each hair strand (the cuticle), increasing friction between fibers and causing frizz. Open cuticles also absorb too much water, which weakens the hair over time. People who have used baking soda regularly as a shampoo replacement report brittle, weak hair after a few months to a couple of years. Some noticed severe breakage, and others found damage within weeks. Pairing it with an apple cider vinegar rinse to “rebalance” the pH doesn’t always prevent the damage.
For a single wash when you have nothing else, baking soda mixed with water (about one tablespoon in a cup of water) will get your hair clean. Just don’t make it a routine.
Apple Cider Vinegar Rinse
Apple cider vinegar has a pH between 2 and 3, making it acidic enough to help smooth the hair cuticle and remove light residue. It won’t replace shampoo for heavy cleaning, but it can refresh hair that feels dull or slightly oily, and it works well as a follow-up after any alkaline wash like baking soda or castile soap.
The standard dilution is 2 to 4 tablespoons of apple cider vinegar in 16 ounces (about 2 cups) of water. Pour it over your hair after your primary wash, let it sit for a minute or two, then rinse. Your hair will smell like vinegar while wet, but the scent fades as it dries. Because the acidity falls below the natural pH of both the scalp and hair shaft, it tends to leave hair feeling smoother and shinier. No research has directly confirmed that it “regulates” hair pH long-term, but as an occasional rinse, it’s safe and effective.
Castile Soap
Liquid castile soap is a true soap made from plant oils, and it lathers and cleans much like shampoo. About half a tablespoon applied directly to your scalp, or diluted in half a cup of water for a thinner consistency, is enough for a full wash. It cuts oil and removes dirt reliably.
The catch is that castile soap is alkaline, so it lifts the hair cuticle in much the same way baking soda does. You need to follow it with an acidic rinse (the apple cider vinegar mixture above works perfectly) to smooth the cuticle back down. Skip the rinse, and your hair will feel waxy, rough, or tangled. With the rinse, the result is surprisingly close to a normal shampoo-and-conditioner routine. If you keep castile soap around for household cleaning, this is a reliable backup.
Cornstarch as a Dry Shampoo
When you can’t get your hair wet at all, cornstarch absorbs oil the same way commercial dry shampoo does. Sprinkle a small amount onto your roots, let it sit for two to three minutes, then brush or massage it through. It soaks up excess sebum and adds volume to flat, greasy-looking hair.
On light hair, cornstarch blends in easily. On dark hair, mix in a small amount of unsweetened cocoa powder to avoid a visible white cast. Don’t rely on cornstarch daily, since it can accumulate on the scalp and dry your hair out over time, but once or twice a week as a stopgap works fine.
Rye Flour
This one sounds unusual, but rye flour has a long track record as a natural hair cleanser in parts of Europe. It contains minerals, amino acids, and B vitamins that support hair, and its fine texture creates a paste that absorbs oil without the extreme alkalinity of baking soda. Use medium-ground rye flour (not whole grain, which leaves bits in your hair). Mix two to three tablespoons with enough water to form a thin, pourable paste, apply it to wet hair, massage for a couple of minutes, and rinse thoroughly. A whisk or shaker bottle helps prevent clumps.
Water Only
If you truly have nothing else, warm water and thorough scalp massage will remove some dirt and loose debris, but water alone doesn’t break down oil. Sebum and water repel each other, so your hair will still feel greasy afterward. Mechanical scrubbing with your fingertips helps, and rinsing with warm (not hot) water loosens oil slightly more than cold.
Some people adopt water-only washing permanently, and their scalps eventually adjust by producing less oil. That transition period typically lasts anywhere from a few weeks to several months, during which hair often looks and feels greasier than usual as the scalp overcompensates for the absence of detergent. For a single day without shampoo, water and a good brush will get you through, but it’s the least effective option on this list.
Why pH Matters for All of These
The common thread with every shampoo alternative is pH. Your scalp is healthiest at around 5.5, and your hair strands are naturally more acidic than that. Products or ingredients that stay at or below 5.5 tend to leave hair smooth and manageable. Anything significantly above that range forces open the cuticle, creating frizz, static, and, over time, breakage.
This is why baking soda (pH 9) carries more risk than apple cider vinegar (pH 2 to 3), and why following any alkaline wash with an acidic rinse makes a real difference. For a one-time substitute, most of these options are perfectly safe. If you’re considering a longer-term switch away from shampoo, stick with options that respect the natural acidity of your hair: co-washing, diluted vinegar rinses, or rye flour, rather than baking soda or undiluted soap.