Tetrahydrocurcuminoids

What tetrahydrocurcuminoids are

Tetrahydrocurcuminoids, often shortened to THC, are made from curcuminoids extracted from turmeric root, Curcuma longa. Curcuminoids are intensely yellow, which limits how much of them a cream can carry. Hydrogenation turns them into tetrahydrocurcuminoids, which are colorless. The result keeps the antioxidant strength of turmeric in an off-white powder that can go into white creams and color-free products without staining them or the skin.

THC sits with the antioxidant and brightening materials in our cosmetic actives section. If you want turmeric in a yellow, bioavailable complex instead, compare it with curcumin phytosome.

Composition and label INCI

The INCI is Tetrahydrodiferuloylmethane, the INCI name for tetrahydrocurcumin, CAS 36062-04-1. The material is an off-white to creamy white crystalline powder. The supplier analysis for this grade gives a tetrahydrocurcumin content of 96.47%.

What it does in skin care

THC is phenolic and acts as an antioxidant: it scavenges free radicals created by sunlight, pollution and other environmental stress, and helps stop new ones from forming. Studies report that it can be even more effective than curcuminoids at lower concentrations. It also inhibits tyrosinase, the enzyme behind melanin formation, so it is used in products for a brighter, more even tone. It has been tested for topical use with no irritation or sensitization reported. As a bonus, it slows the oxidation of oils and butters in a formula, which helps protect the product itself from rancidity.

How to use it

THC does not dissolve in water, so solubilize it first in a suitable solvent. It is soluble in ethoxydiglycol, soluble in propylene glycol at about 1 part to 8 parts at 40 °C, soluble in polysorbate 20 at about 1 to 4 at 40 °C, and partly soluble in dimethyl isosorbide and ethanol. Add the solution to the emulsion at or below 40 °C. Keep the finished pH slightly acidic, ideally 5.0 to 6.5.

Formulation rules

Use stainless steel vessels and avoid contact with iron or copper, which can discolor the material. Emulsions should be nonionic or anionic, not cationic. THC suits creams, lotions and translucent to opaque gels and serums, and it can be thickened with carbomer, acrylate copolymers or lecithin. It is not suitable for crystal clear gels, serums or toners. Adding other antioxidants and photostabilizers to the formula is recommended.

Bench example: brightening gel-cream

This 100 g bench batch shows one way to use the material. For the premix, warm 4 g propylene glycol to 40 °C and dissolve 0.5 g tetrahydrocurcuminoids in it. For phase A, weigh 76.7 g distilled water, 3 g glycerin and 0.3 g carbomer, and disperse the carbomer fully. For phase B, weigh 8 g caprylic/capric triglyceride and 3 g of a nonionic cold-process emulsifier. Blend phase B into phase A, neutralize the carbomer to pH 5.5, then add the THC premix, 2 g niacinamide, 0.5 g tocopherol, 1 g broad-spectrum preservative used at its supplier rate and 1 g water to rinse the premix beaker. Mix until smooth.

Where it fits in a product line

THC suits brightening creams, even tone serums, eye creams and hand creams, and it doubles as a natural antioxidant that helps protect the oils in a formula. Because it is colorless, it gives turmeric based claims in white and pastel products.

Storage

Keep the powder in a tightly closed container in a cool, dry place away from light. Close the pack quickly after each use. For cosmetic formulation use only.