General HSK Requirement
In generally, HSK is required for the students who want to study in China, but for some programs it’s not necessary, which determined by different universities.
According to the regulation of MOE,China, international students could apply the China universities to study according to their own HSK level certificate. That is to say, the HSK certificate is a guarantee for the students’ studying in China. Because for the students who want to study in China, many courses are taught in Chinese except some special taught in English.
Special HSK Requirement
As for the programs which were taught in English, students need supply related documents to your target university. Because different universities has different requirements for HSK. Some universities will not compulsory ask the higher HSK level, but to some point they may need communicate with you through Skype in simple Chinese. Before you supply the required documents, you must contact with the university’s teacher and consult with them about the HSK requirement.
For example, Master programs taught in English (Medicine) in Liaoning Medical University has requirement for the HSK although the program taught in English, its HSK requirement for this program is get the HSK3 certificate.
Therefore, for the programs taught in English in China, the best answer for HSK requirement must be in the school's recruiting brochure, or you can get the answer by communicating with teachers from your target university.