Menthol Crystals (Pudina ke Phool): Uses and Safety

Menthol is the main cooling compound in mint oil, especially from corn mint (Mentha arvensis), which India grows on a large scale. The clear needle-like crystals are sold in Indian markets as pudina ke phool (पुदीना के फूल). It doesn't actually lower temperature. It triggers the cold-sensing nerves in the skin and mouth, so you feel a cooling effect.

• Formula: C10H20O
• CAS number: 2216-51-5 for L-menthol, the natural-type form; 89-78-1 for racemic menthol
• Molar mass: about 156.3 g/mol
• Melting point: about 42 to 45 °C for L-menthol crystals
• Boiling point: about 212 to 215 °C
• Solubility: only slightly soluble in water, dissolves easily in alcohol, oils and glycols

Because it melts just above room temperature, crystals can stick together or turn mushy in an Indian summer if the jar is left in a hot place.

Azlok lists Menthol Crystal Bold (Edible Grade). "Bold" refers to the larger crystal size. The edible grade label means it's meant for flavour use in foods and mouth fresheners, within FSSAI limits for flavouring agents. The listing name doesn't state a pack weight, so check the product page.

See today's price per kg.

• Food and mouth fresheners: mukhwas, paan masala-type mixes, candies, chewing gum and mint flavours.
• Oral care: the cool, fresh taste in toothpaste and mouthwash.
• Personal care: cooling hair oils, prickly-heat style talcs, shaving products, shampoos, soaps and after-sun gels.
• Balms and rubs: the cooling note in traditional balms and rubs.
• Perfumery and flavour houses: mint, fresh and cooling accords, and tobacco flavours.

• Dissolve before adding. Menthol won't mix into water. Dissolve it first in ethanol, a carrier oil, propylene glycol or melted wax, then add that to your product.
• Gentle warming helps. In oils it dissolves faster if the oil is warmed to about 40 to 50 °C. Keep the lid on or work quickly, as the vapour is strong.
• Start low. In leave-on cosmetics like hair oil, talc or lotion, typical levels are about 0.1 to 1%. Rinse-off products such as shampoo or soap often use a bit more. Above that, it can sting and redden skin.
• Food: use only the edible grade, in tiny amounts, and follow FSSAI rules for flavouring agents. A few crystals flavour a large batch.

Patch test any finished cosmetic on the inner arm for 24 hours. Finished cosmetics sold in India also need to meet the applicable BIS and CDSCO rules.

• Neat crystals and strong solutions burn the eyes and can irritate skin. Use gloves, and don't rub your eyes while handling it.
• The vapour is strong in a closed room. Work with some ventilation.
• Don't use menthol products on or near the face of infants and small children. Strong menthol vapour can affect their breathing.
• Large amounts swallowed are harmful. Keep it locked away from children.
• Store in a tightly closed glass or HDPE jar in a cool place, below about 25 °C, away from sunlight. Heat makes crystals soften, stick and lose aroma.
• It is combustible. Keep away from open flames when melting or dissolving.
• Dispose of small amounts in normal waste in a sealed bag.

For mouth fresheners and food, use only the edible grade. For hair oil, balm, talc and soap, the same crystals work well, since one grade covers both needs.

Because menthol is used in small amounts and is strongly scented, a small pack lasts a home maker a long time. Small balm, hair oil and mukhwas businesses using it weekly can buy larger quantities, but should have cool storage. For 25 kg or more, ask through the bulk inquiry page.