Sodium bicarbonate, commonly known as baking soda, is a household staple with uses beyond baking and cleaning. This white, crystalline powder is a naturally occurring mineral compound valued for its mild abrasive and deodorizing properties. Its reputation as a cost-effective, readily available alternative has made it a popular choice for those seeking a more natural personal care regimen for managing underarm odor.
The Science of Odor Neutralization
Body odor is caused by the metabolic activity of bacteria living on the skin, particularly in moist areas like the underarms. Sweat from the apocrine glands is rich in fats and proteins, which bacteria break down into volatile fatty acids. These fatty acids are responsible for the characteristic pungent smell.
Baking soda manages odor because it is an alkaline substance, registering between 8.5 and 9.0 on the pH scale. This alkalinity chemically reacts with the acidic volatile fatty acids produced by the bacteria. The reaction converts the malodorous acids into non-smelly salt compounds, effectively neutralizing the odor.
By raising the pH of the underarm environment, baking soda creates conditions less favorable for odor-causing bacteria. The powder also has mild moisture-absorbing qualities, helping to keep the area drier. This combination significantly reduces the bacteria’s ability to generate acidic odor molecules.
Step-by-Step Application Methods
Dry Application
The simplest way to use baking soda is through a direct, dry application. Ensure the skin is completely clean and dry, ideally after showering, as moisture will cause the powder to clump. Take a pinch or two of the dry powder on your fingertips. Gently rub the baking soda directly into the underarm skin until it is no longer visible as a white residue, applying a thin, even layer.
Paste Application
An alternative method is to create a paste by mixing baking soda with water. Combine about one-eighth to one-quarter teaspoon of baking soda with a few drops of lukewarm water until a thin, spreadable slurry forms. Apply this mixture to the entire underarm area using your fingertips, rubbing it in thoroughly. Let the applied paste dry completely before putting on clothing to ensure the baking soda remains in contact with the skin and prevents transfer onto fabric.
Addressing Skin Irritation and Sensitivity
The high alkalinity of baking soda is the primary reason some users experience side effects like redness, itching, burning, or a rash. Healthy skin maintains a slightly acidic surface, known as the acid mantle, with a pH ranging from 4.5 to 5.5. Applying a substance with a pH of 8.5 or higher disrupts this natural balance, compromising the skin’s protective barrier.
This disruption leads to irritation, especially in the sensitive underarm skin. To prevent sensitivity, a patch test is recommended before full application. Apply a small amount to a discreet area, such as the inside of the elbow, and monitor the skin for 24 hours.
If irritation occurs, stop using the baking soda temporarily to allow the acid mantle to repair itself. When resuming use, reduce the concentration by using less powder or applying it less frequently. Avoiding use immediately after shaving and ensuring the skin is completely dry before application can also mitigate the risk of dermatitis.
DIY Baking Soda Deodorant Variations
For individuals who find the pure baking soda or simple paste methods too harsh, buffering the alkalinity through a DIY recipe is a common solution. The goal of these variations is to dilute the concentration of sodium bicarbonate while retaining its odor-neutralizing power. This is achieved by combining the powder with other gentle, functional ingredients.
A popular variation involves mixing baking soda with absorbent powders like cornstarch or arrowroot powder. These powders act as a physical buffer, reducing the concentration of the alkaline substance while absorbing moisture to enhance dryness. This combination can be used as a gentler dusting powder.
To create a moisturizing cream or solid, carrier oils or butters are added to the dry mixture. Coconut oil is frequently used due to its natural antibacterial properties and its ability to solidify at room temperature. Shea butter or cocoa butter can also be incorporated to provide a smoother, more conditioning texture. These fatty ingredients encapsulate the baking soda particles, ensuring a more even and less abrasive application on sensitive skin.