Also known as: ACV, Acetic acid, Mother vinegar, ACV gummies, Cider vinegar
Fat MetabolismEmerging evidence
Fermented apple juice, sold on claims that considerably exceed what the research supports. The blood sugar effect is modest but real; the weight loss effect is small; and the dental warning is the most useful thing on this page.
Typical dose
15.0–30.0 ml per day
Diluted, before or with carbohydrate-containing meals
What it is
Apple cider vinegar is made by fermenting apple juice twice: first to alcohol, then to acetic acid. Acetic acid typically makes up around 5 to 6 per cent of the finished product and is responsible for essentially all of its biological activity.
The mother is the cloudy sediment of bacteria and cellulose formed during fermentation. It is much fussed over in marketing, and there is very little evidence that it contributes anything beyond appearance. Filtered vinegar contains the same acetic acid.
Gummies deserve a specific mention. Most contain a fraction of the acetic acid in a tablespoon of liquid vinegar, and many contain added sugar. If the acetic acid is the active component, and it is, then a gummy supplying very little of it is not delivering the thing the research studied.
How it works
Acetic acid appears to slow gastric emptying, meaning a meal leaves the stomach more gradually. That produces a flatter blood glucose rise after eating and may increase the feeling of fullness.
It also appears to interfere with the enzymes that break down starch, reducing how quickly carbohydrate is digested, and may improve glucose uptake into muscle.
These mechanisms are real but modest, and they are specific to carbohydrate-containing meals. Taking vinegar away from food, or before a meal with little carbohydrate, has much less to act on — which is why timing matters more than dose here.
What the evidence shows
The blood glucose finding is the most consistent. Trials have repeatedly shown that vinegar taken with a carbohydrate meal reduces the post-meal glucose rise, and meta-analyses have supported this.
Weight loss evidence is much weaker. Trials reporting effects have generally found differences of around one to two kilograms over several months, and several are small or of limited quality. This is not the transformative effect the category is sold on.
Claims about detoxification, skin, energy and immunity have essentially no supporting evidence. The honest summary is a cheap kitchen ingredient with one modest, reproducible effect on post-meal glucose and a great deal of marketing attached to it.
Dosing
Typical intake is 15 to 30 ml, one to two tablespoons, diluted in a large glass of water and taken before or with a carbohydrate-containing meal.
Never drink it undiluted. This is not a matter of taste — concentrated acetic acid damages tooth enamel and can irritate the throat and oesophagus.
Drink it through a straw and rinse your mouth with plain water afterwards, but do not brush your teeth for at least 30 minutes, since brushing softened enamel accelerates the damage. If you are buying gummies for convenience, check the acetic acid content, because most supply far less than the liquid the research used.
Effects on post-meal glucose are acute and meal-specific
Timing
Diluted, before or with carbohydrate-containing meals
Competition status
Permitted — not on the WADA Prohibited List
Category
Fat Metabolism
Safety and side effects
Diluted apple cider vinegar is safe for most people. Undiluted vinegar is not, and the damage it does is cumulative and irreversible.
Tooth enamel erosion is the best-documented harm, and there are case reports of significant dental damage from habitual undiluted use. Enamel does not grow back. This is the single most important point on this page and the one most often left off product marketing.
Vinegar can also irritate the throat and worsen reflux in some people, and it may lower blood sugar and potassium. Speak to your doctor before regular use if you take regular medication or if your blood sugar or potassium is being monitored.
Who should avoid it
Never drink undiluted — tooth enamel erosion is documented and permanent. Use a straw, rinse with water afterwards, and do not brush your teeth for at least 30 minutes. Take care if you are prone to reflux. Speak to your doctor before regular use if your blood sugar or potassium is being monitored, or if you take regular medication.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
