Answer:Although several small studies suggest apple cider vinegar may be helpful for weight loss or lowering blood sugar levels in some people, larger studies confirming these findings are needed before apple cider vinegar can be relied upon for these uses.
ConsumerLab has purchased and tested popular apple cider vinegars, including those in pill form. The tests revealed many high-quality products, including those judged to be CL's Top Picks, but also some that may contain so much acetic acid as to be considered poison. See the results in the Apple Cider Vinegars (Bottled Liquids and Pills) Review. The Review also explains, in details, the evidence for and against apple cider vinegar, how to use it, potential side effects, and more.
Also see these related CL Answers:
Which supplements can help lower or control my blood sugar? >>
What is berberine? Can it really lower blood sugar? Are there any cautions? >>
I take insulin (Humalog) for diabetes. Are there supplements which could affect my blood sugar levels, and how much insulin I need to take? >>