Baking soda – or sodium bicarbonate – sits comfortably in kitchen cupboards yet stirs debate when it wanders into cosmetic jars. As a crystalline white powder with a mildly alkaline pH of about 8.3, it excels at neutralizing acids, releasing carbon dioxide gas in the process – hence its leavening fame. On skin, that effervescence provides a gentle micro-scrub, while the alkalinity temporarily lifts the stratum corneum’s pH, softening intercellular bonds so dead cells shed more readily.

DIY circles tout baking-soda pastes for everything from blackhead extraction to deodorant, but dermatologists raise red flags. The acid mantle, ideally sitting around pH 4.7, orchestrates enzymatic ceramide synthesis and wards off pathogens like Staphylococcus aureus. Repeated baking-soda exposure can keep the mantle stuck in alkaline territory, crippling barrier function and setting the stage for irritant dermatitis. A 2018 Skin Research & Technology study showed that volunteers who washed hands with a 5-percent sodium-bicarbonate solution twice daily exhibited a 40-percent spike in TEWL after one week.

Formulators who harness baking soda do so judiciously. In deodorants, its alkalinity hampers the enzyme urease that turns sweat into malodorous ammonia. Micro-encapsulation blunts the pH jolt, releasing bicarbonate incrementally in response to moisture. In facial cleansers, concentrations below one percent provide fizz without overshooting pH 6 when combined with citric acid buffers.

For consumers, an occasional baking-soda-infused bath soak can soothe itchy bug bites thanks to its anti-pruritic effect, but face masks should remain short (five minutes max) and follow with a mildly acidic toner or essence to reset pH. Those with eczema, rosacea, or compromised barriers should skip the trend altogether. If the desire for a fizzy exfoliation persists, consider products that pair sodium bicarbonate with ascorbic acid – think effervescent vitamin C powders – where the two neutralize each other mid-reaction, ending near skin-friendly pH.

Baking Soda (Wikipedia)

Not to be confused with Sodium carbonate.

For the leavening agent of which baking soda is a common ingredient, see Baking powder.

Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO₃. It is a salt composed of a sodium cation (Na⁺) and a bicarbonate anion (HCO−3). Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is nahcolite, although it is more commonly found as a component of the mineral trona.

Sodium bicarbonate

Crystal structure
Na+ coordination HCO3− coordination
Names
IUPAC name sodium hydrogencarbonate
Other names Baking soda, bicarb (laboratory slang), bicarbonate of soda, nahcolite, natrium hydrogen carbonate, natron
Identifiers
CAS Number	144-55-8 Y
3D model (JSmol)	Interactive image
Beilstein Reference	4153970
ChEBI	CHEBI:32139 Y
ChEMBL	ChEMBL1353 Y
ChemSpider	8609 Y
DrugBank	DB01390 Y
ECHA InfoCard	100.005.122
EC Number	205-633-8
E number	E500(ii) (acidity regulators, ...)
IUPHAR/BPS	4507
KEGG	C12603 Y
MeSH	Sodium+bicarbonate
PubChem CID	516892
RTECS number	VZ0950000
UNII	8MDF5V39QO Y
CompTox Dashboard (EPA)	DTXSID9021269
InChI InChI=1S/CH2O3.Na/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 Y Key: UIIMBOGNXHQVGW-UHFFFAOYSA-M Y InChI=1/CH2O3.Na/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 Key: UIIMBOGNXHQVGW-REWHXWOFAQ
SMILES [Na+].OC([O-])=O
Properties
Chemical formula	NaHCO 3  Y
Molar mass	84.0066 g mol−1
Appearance	White crystals
Odor	Odorless
Density	2.20 g/cm3
Melting point	(Decomposes to sodium carbonate starting at 50 °C)
Solubility in water	69 g/L (0 °C) 96 g/L (20 °C) 165 g/L (60 °C)
Solubility	0.02 wt% acetone, 2.13 wt% methanol @22 °C., 1 in 10% in water @25 °C, insoluble in ethanol
log P	−0.82
Acidity (pKa)	6.34 6.351 (carbonic acid)
Refractive index (nD)	nα = 1.377 nβ = 1.501 nγ = 1.583
Structure
Crystal structure	Monoclinic
Thermochemistry
Heat capacity (C)	87.6 J/mol K
Std molar entropy (S⦵298)	101.7 J/mol K
Std enthalpy of formation (ΔfH⦵298)	−950.8 kJ/mol
Gibbs free energy (ΔfG⦵)	−851.0 kJ/mol
Pharmacology
ATC code	B05CB04 (WHO) B05XA02 (WHO), QG04BQ01 (WHO)
Routes of administration	Intravenous, oral
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Causes serious eye irritation
NFPA 704 (fire diamond)	2 0 1
Flash point	Incombustible
Lethal dose or concentration (LD, LC):
LD50 (median dose)	4220 mg/kg (rat, oral)
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Sodium carbonate
Other cations	Ammonium bicarbonate Potassium bicarbonate
Related compounds	Sodium bisulfate Sodium hydrogen phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

As it has long been known and widely used, the salt has many different names such as baking soda, bread soda, cooking soda, brewing soda and bicarbonate of soda and can often be found near baking powder in stores. The term baking soda is more common in the United States, while bicarbonate of soda is more common in Australia, the United Kingdom, and New Zealand. Abbreviated colloquial forms such as sodium bicarb, bicarb soda, bicarbonate, and bicarb are common.

The prefix bi- in "bicarbonate" comes from an outdated naming system predating molecular knowledge. It is based on the observation that there is twice as much carbonate (CO2−3) per sodium in sodium bicarbonate (NaHCO₃) as there is in sodium carbonate (Na₂CO₃). The modern chemical formulas of these compounds now express their precise chemical compositions which were unknown when the name bi-carbonate of potash was coined (see also: bicarbonate).