I am Emmanuel, engaged in selling L-Histidine in Russia, thus, it is extremely important for me to select a reliable supplier of L-Histidine.
Google “Company Name”
A renowned company name usually shows a great deal results on Goolge Search, because its company name is frequently searched by their customers or cited by other web sites.
Take “Foodchem International Corporation” as an example, as has been showed in the below picture, there comes out more than 298,000 searching results on Google. 
Warehouse
Warehouse is also important for L-Histidine suppliers, L-Histidine traders make judgments through L-Histidine market situation. On one hand, while L-Histidine is in the upside, traders purchase bulk L-Histidine for storage, and sell with the price advantage; On the other, vendors need to keep cargo in warehouse in case customers need LCL loaded.
Foodchem International Corporation owns an EDC warehouse in Shanghai, an advanced warehouse system which only few trading companies in Shanghai can provide, it avails fast delivery within 1 week.
Sales of Supplier
There are tons of suppliers of L-Histidine in China, thus, supply scale should be important, L-Histidine suppliers with a certain size suppliers tend to have more bargaining power, in some country, we can even find their L-Histidine supply volumes through customs data.
History of Supplier
History counts for a lot, a supplier with long history in the L-Histidine industry has a wealth of experience to accurately grasp the L-Histidine market, most of unexpected problems can be solved timely and accurately. The Chinese government gives all the enterprise a issued business license, from which history of enterprises can be found. Under such a fierce competition of L-Histidine market, enterprises who can survive over five years can normally be trusted.
The picture below shows the license certificate of Foodchem International Corporation, China’s leading supplier of food additive and food ingredients with establishing year of more than 8.
Certificate
A formal operation supplier of food additives normally passes ISO certificate as well as other well-known certificate like halal, kosher, ect.
Supply of Products
Compared with Manufacturers, other than service advantage, main advantage of trading companies lies in being able to provide various kinds of products. For example, when we would like to order L-Histidine as well as several other food ingredients, trading companies becomes the best choice, since unlike factories, traders can provide one-stop service and have greater bargaining powder which permits a lower price.
Of course , we can purchase L-Histidine directly from manufacturers if the volume is large enough, but it won’t be a bad choice if we keep in touch with some large-scaled traders. Because once your long-term-cooperate factory is in short of L-Histidine , we can turn to trading companies, who can help to find other suppliers shortly or even direct supply L-Histidine in no time.
As far as we know, big suppliers of food additives and ingredients can basically provide more than 100 kinds of products, among which, Foodchem International Corporation are able to supply overseas customers more than 300 kinds of food additives and ingredients, plant extracts, nutritional supplements, apis, etc.
Size of Team
Member Size of suppliers or manufacturers also plays a very important role; generally number of manufacturers is slightly larger than traders. A complete overseas trade involves a lot of sessions; To perform perfectly, each session requires well-professional persons. A well-founded overseas trading company generally includes online marketing, sales, logistics, purchasing, service, administration departments, etc.
Normally we can scan through the vendor’s web site or some third-party social networking sites to confirm suppliers’ team size.