To find information about magnesium lactate merchants or distributors in China, we may consider the following steps:

1. Online Directories: We can search for online business directories and trade websites that list companies and distributors of chemical and food products.Websites like Alibaba, Made-in-China, and Global Sources are good places to start.

2. Contact Manufacturers: Reach out to manufacturers of magnesium lactate or related products and inquire about their distribution channels in China.They may be able to provide us with a list of authorized distributors or merchants.

3. Trade Associations: Contact relevant trade associations or industry groups related to the food or chemical industry in China.They may have information on key players in the distribution of such products.

4. Trade Shows and Exhibitions: Attend trade shows, exhibitions, or industry events related to food additives, chemicals, or pharmaceuticals.These events often attract distributors and merchants looking to connect with suppliers.

5. Local Business Networks: If we are in China or have contacts in the country, consider tapping into local business networks and connections.   Personal recommendations and word-of-mouth referrals can be valuable in identifying reliable merchants.

6. Consult with Experts: Consult with professionals in the field of food additives or chemical distribution in China.They may have insights into the industry's key players and distribution networks.

Conduct due diligence when choosing a distributor, including verifying their credentials, reputation, and compliance with relevant regulations and quality standards.Additionally, consider seeking legal and business advice when entering into distribution agreements or partnerships.