Melting point	275-277°C (dec.)
density	1.2541 (rough estimate)
refractive index	1.6740 (estimate)
storage temp.	-20°C
solubility	Soluble in Water (up to 10 mg/ml)
form	White solid.
color	White or off-white
Stability:	Stable for 1 year from date of purchase as supplied. Solutions in water may be stored at -20°C for no more then 1 day.
EPA Substance Registry System	1H-Imidazole-4-ethanaminium, .alpha.-carboxy-2,3-dihydro-N,N,N-trimethyl-2-thioxo-, inner salt, (.alpha.S)- (497-30-3)

Ergothioneine is a natural antioxidant and a unique cell physiological protective agent. It has many physiological functions such as scavenging free radicals, whitening, anti-aging, preventing UV radiation damage, maintaining DNA synthesis and normal cell growth.It has the following functions.

1. Whitening
Ergothioneine is a kind of natural antioxidant, which is highly protective and non-toxic to cells. It is not easy to be oxidized in water, which makes the concentration of Ergothioneine in some tissues reach 7mmol-l, and stimulates the natural antioxidant defense system of cells. The results show that the amount of Ergothioneine in cosmetics can reach 0.01% - 0.03%, which can hinder the formation and calmness of pigment and whiten the skin.

2. Antioxidation: high efficiency, anti-oxidation, anti-aging.
L'Oreal has applied for a patent entitled "use of Ergothioneine and / or its derivatives as an anti glycation agent". It is proposed that Ergothioneine and its derivatives can reduce or even prevent protein glycosylation, so as to prevent age-related skin elasticity loss, modify and improve facial contour, and prevent or improve the appearance of orange peel lines.

3. Sun protection 
In the range of ultraviolet absorption, Ergothioneine has the absorption wavelength similar to DNA, and the molar extinction coefficient is 1.4*104 M-1 cm-1, λ max257, which can reduce the formation of active oxygen to the greatest extent, and protect cells from radiation damage. Therefore, Ergothioneine can be used as a biological filter of ultraviolet. Several reports have shown that Ergothioneine is a very effective sunscreen because it can avoid the skin damage caused by ultraviolet radiation.

4. Eliminate inflammation and acne
Inflammation is the response of the body when the skin is infected. Excessive ultraviolet radiation and excessive pressure are the causes of skin inflammation. Research shows that Ergothioneine can play an anti-inflammatory role in skin cells, and at the same time, the combination of Ergothioneine and vitamin C will achieve more significant effect. Elizabeth Arden has done the application experiment of Ergothioneine in the repair of UV induced skin inflammation, which shows that the combination of Hydroxydecyl ubiquinone and Ergothioneine can reduce the UV induced skin inflammation and light damage.   
         
5. Synergy
 Ergothioneine can regulate the redox reaction in cells and participate in the energy regulation in cells. It is the physiological protective agent of cells. It has biological and pharmacological characteristics and is safe and stable. Therefore, the addition of Ergothioneine in a product can not only maintain the stability of other components, but also promote the absorption of active components by cells, it has a good synergistic effect, effectively enhance the efficacy of other components, and achieve the effect of 1 + 1 > 2. For example, when Ergothioneine is used in an antioxidant product, it can not only exert strong antioxidant effect, but also cooperate with other antioxidants to take effect and enhance its vitality.