Liquid vinegar taken with a meal blunts the sugar rise after that meal, but the pills and gummies on store shelves were never part of those studies.
Apple cider vinegar is one of the two supplements people ask me about most. (Cinnamon is the other.) And there's good news here, with a twist.
Vinegar with a meal really does help with the spike after that meal. But the form that was tested is plain liquid vinegar, with food. The pills and gummies are sold on the strength of those studies, even though they were never part of them.
The book's grade: PLAUSIBLE (might help) for liquid vinegar with meals, for after-meal spikes, with weak evidence for A1c. NO EVIDENCE (not tested properly) for vinegar pills, capsules and gummies.
What the studies found
Vinegar with meals. A review of trials found that vinegar taken with a meal lowered the after-meal rise in blood sugar and insulin (review of meal trials). That effect was measured after single meals. It happens at that same meal, and it doesn't prove a lower A1c.
A1c and fasting sugar. Small, inconsistent studies of liquid vinegar point the right way. A 2025 review of apple cider vinegar in type 2 diabetes found only 7 studies. It reported an A1c drop of 1.5%, which is far too large to trust from so few (2025 review). So I'm fairly sure about the one-meal spike, and not sure about A1c.
Pills. Barely tested. In one small 12-week study of 27 people with type 2 diabetes, a store-bought vinegar pill (about 30 mg of acid a day) was the comparison. A1c rose 0.06% on the pill and fell 0.16% with liquid vinegar (12-week study). A 2026 trial of apple cider vinegar capsules in women with polycystic ovary syndrome (PCOS) reported better insulin resistance, but it didn't include people with diabetes (PCOS trial).
Gummies. I found no trials of vinegar gummies on blood sugar.
Why it might work
Vinegar slows how fast your stomach empties. So food from the meal reaches your blood more slowly (stomach-emptying study). The likely active part is acetic acid, the acid that makes vinegar sour.
Here's my reasoning on the pills, and it's only reasoning, not tested: a pill swallowed without a meal has no meal to slow down.
Safety
- Gastroparesis. This is a condition, more common in long-standing diabetes, where nerve damage makes the stomach empty too slowly. In 10 people with type 1 diabetes and gastroparesis, 2 tablespoons (30 mL) of apple cider vinegar slowed emptying even more (gastroparesis study). That can make blood sugar harder to predict. If you have gastroparesis, or often feel full long after small meals, skip vinegar in any form.
- Your teeth. In an 8-week trial, healthy adults drank 2 tablespoons of vinegar in a cup of water twice a day. Wear on their tooth enamel went up 18% (enamel trial). Vinegar is an acid, so never drink it straight. Dilute it, take it with food and rinse your mouth with plain water after.
- Pills can burn. One report describes an injured throat (esophagus) from an apple cider vinegar tablet (case report). Skip pills if you have trouble swallowing them.
- Gummies are candy. They're generally safe, but count the sugar.
- Labels can't be trusted. When 8 vinegar tablet brands were tested, their acid content and label claims varied widely. It wasn't clear they held vinegar at all.
What I tell my patients
Skip the pills and gummies. Plain vinegar costs far less, and it's the form that was actually tested.
The easiest way to use it is in your food. Make a vinegar-and-oil dressing and eat a salad first. That pairs vinegar with eating your vegetables first, another simple habit I cover in the book.
Before you start, ask your doctor or pharmacist: "Is vinegar with meals safe for my stomach and my diabetes medicines?"
There's a small bonus, too, though the evidence is low quality and comes from liquid vinegar. Each 30 mL (2 tablespoons) a day lowered the top and bottom blood pressure numbers by about 3 points each (blood pressure review). Total cholesterol went down about 6 mg/dL with apple cider vinegar (cholesterol review).
Bottom line
Vinegar with a meal may blunt the spike after that meal. Use it in food, always diluted, and skip it if you have gastroparesis. Don't expect a big A1c change, and don't buy the pills or gummies. They ride on studies they were never part of.
Questions people ask
Does apple cider vinegar lower A1c?
Not clearly. Small, inconsistent studies of liquid vinegar point the right way. One 2025 review reported a 1.5% drop, but it was based on only 7 studies, which is far too few to trust a number that large. The solid finding is a smaller rise after the meal you eat it with.
Do apple cider vinegar gummies work for blood sugar?
There's no evidence they do. I found no trials of vinegar gummies on blood sugar. The studies used liquid vinegar with meals. Gummies are candy, so count the sugar.
How should I take apple cider vinegar with meals?
With food, never straight. A vinegar-and-oil dressing on a salad you eat first is the easiest way. If you drink it, dilute it in water and rinse your mouth with plain water after to protect your teeth. Skip it if you have gastroparesis.
Get the real number for every food and supplement
Vinegar is one of many kitchen tricks and supplements I grade in Your A1c by the Numbers. Each one gets an evidence grade and a real number, so you know what's worth trying. Take a look at more short reads.