Pantolactone is a cyclic organic compound derived from pantothenic acid (vitamin B5) and is often used in cosmetic and personal care products for its moisturizing and soothing properties. It is known for improving the elasticity of skin and hair, promoting hydration, and supporting cellular regeneration. Pantolactone is commonly found in creams, lotions, shampoos, and hair care products.

Chemical Composition and Structure
Pantolactone is a lactone, a cyclic ester derived from pantothenic acid. Its chemical structure features a lactone ring that stabilizes the molecule, making it a functional ingredient in cosmetic formulations. This structure enables Pantolactone to act as a humectant, attracting and retaining moisture, thus contributing to skin and hair hydration.

Physical Properties
Pantolactone appears as a white or colorless crystalline substance, soluble in water. It has good chemical stability and maintains its efficacy across a wide range of cosmetic formulations. Its moisturizing and conditioning properties make it a versatile ingredient in personal care products.

The name defines the structure of the molecule:

• "Panto" comes from the Greek word "Pantos" which means "everything". This is a reference to the presence of the compound in almost all living cells as part of pantothenic acid as a molecule (vitamin B5).
• "lactone" is a term used in organic chemistry to describe cyclic esters. An ester is a compound derived from an acid, in this case, a carboxylic acid, in which at least one hydroxyl-OH group is replaced by an alkyl-O-alkyl group. When this ester forms a ring structure, it is called lactone.

Production Process
Pantolactone is synthetically produced through the cyclization of pantothenic acid, a process that forms its characteristic lactone ring. The production of Pantolactone is carefully controlled to ensure purity and effectiveness in cosmetic applications. 

• Step 1: Preparation of raw materials. The raw materials for the synthesis of pantolactone are generally an aldehyde and ketone suitable.
• Step 2: Aldol Reaction. Aldehyde reacts with ketone in the presence of a suitable catalyst to produce an Aldol product. This reaction is typically catalyzed by a chiral organocatalyst, such as L-histidine-modified-ionic-liquid.
• Step 3: Hydrogenation. Aldol is hydrogenated to produce pantolactone. This step is typically catalyzed by a suitable hydrogenation catalyst, such as Cu-/sio2.
• Step 4: Purification and drying. The resulting pantolactone is then purified, typically through filtration and washing, and dried.

What it is for and where

 It is a cyclic organic compound with a functional lactone group. This compound is often used as a starting material in the synthesis of various pharmaceutical products.

• Skin Care: Pantolactone is used in creams and lotions for its moisturizing and regenerative properties. It helps improve skin elasticity, reducing dryness and promoting smooth, supple skin.

• Hair Care: In hair care products like shampoos and conditioners, Pantolactone acts as a conditioning agent, improving hair softness and shine. It also aids in repairing damaged hair and helps retain moisture.

• Anti-Aging Products: Due to its hydrating and regenerating properties, Pantolactone is often included in anti-aging formulations to improve skin appearance by reducing visible signs of aging, such as wrinkles and fine lines.

INCI Functions:

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis.  The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Other uses

It can be used as a pharmaceutical reference standard for the quantification of the analyte in pharmaceutical formulations by gas chromatography.

It has demonstrated significant antimicrobial activity (1).

Health and Safety Considerations

Skin Safety
Pantolactone is generally considered safe for use in cosmetic products. It is well-tolerated by most skin types and is not known to cause significant irritation or sensitization. Its ability to soothe and hydrate makes it ideal for use in products for sensitive skin.

Allergic Reactions
Allergic reactions to Pantolactone are rare. However, as with any ingredient, individuals with very sensitive skin should perform a patch test before regular use.

Toxicity and Carcinogenicity
There is no evidence that Pantolactone is toxic or carcinogenic. It is considered safe for use in cosmetics and personal care products by various regulatory bodies, such as the Cosmetic Ingredient Review (CIR).

Environmental and Safety Considerations
Pantolactone is biodegradable and does not pose a significant threat to the environment. It can be used safely in cosmetics without causing negative environmental impacts, provided proper disposal practices are followed.

Regulatory Status
Pantolactone is approved for use in cosmetic and personal care products in many regions, including the European Union, the United States, and other international markets. It is widely used in skin and hair care formulations.

• Molecular formula: C₆H₁₀O₃
• Molecular Weight: 130.14
• CAS: 599-04-2
• UNII J288D7O0JS
• EC Number: 209-963-3
• DSSTox Substance ID: 
• MDL number  MFCD00005392
• PubChem Substance ID   329823396
• Beilstein/REAXYS Number: 80957

Synonyms: 

• 2,4-dihydroxy-3,3-dimethylbutyric acid gamma-lactone
• D-(-)-Pantolactone

References_______________________________________________________________

(1) Baldé MA, Tuenter E, Matheeussen A, Traoré MS, Cos P, Maes L, Camara A, Diallo MST, Baldé ES, Balde AM, Pieters L, Foubert K. Bioassay-guided isolation of antiplasmodial and antimicrobial constituents from the roots of Terminalia albida. J Ethnopharmacol. 2021 Mar 1;267:113624. doi: 10.1016/j.jep.2020.11362