Apple cider vinegar has enjoyed a reputation as a cure-all for centuries, and if you spend any time on health forums, you’ll find people swearing by it for everything from weight loss to clearing up skin problems. I find the gap between folk wisdom and scientific evidence genuinely interesting here. Some traditional claims hold up reasonably well under scrutiny, while others rest on shaky foundations.

In this article, I want to walk through what researchers have actually found about apple cider vinegar. I’ll cover both the potential benefits and the side effects you should know about, with references to the underlying studies so you can dig deeper if you’re inclined.

What is apple cider vinegar?

Vinegar production dates back to around 5000 BC in ancient Babylon, where it was used as a preservative, flavouring, and folk medicine [1]. Apple cider vinegar specifically comes from fermenting apple juice or crushed apples through a two-stage process.

First, yeast converts the natural sugars in apples into alcohol. Then acetic acid bacteria (Acetobacter species) convert that alcohol into acetic acid, the main active compound. This fermentation can take weeks or months, depending on the method used.

The finished product contains roughly 5-6% acetic acid, along with trace amounts of vitamins (B1, B2, B6, biotin, folic acid, niacin, and small amounts of vitamin C) and minerals (sodium, phosphorus, potassium, calcium, iron, and magnesium). None of these exist in quantities that would make apple cider vinegar a meaningful source of micronutrients, mind you. The acetic acid is really the main player.

Unfiltered, unpasteurised versions contain what’s called “the mother” - a cloudy, cobweb-like substance made up of beneficial bacteria and enzymes. Some people specifically seek this out, though the research on whether the mother provides additional benefits beyond acetic acid remains limited.

Potential benefits of apple cider vinegar

1. Blood sugar control

This is probably the best-supported benefit. A 2017 meta-analysis examining 11 controlled trials with 204 participants found that consuming vinegar with meals significantly reduced both average blood glucose levels and the area under the glucose curve compared to controls [2].

The mechanism appears to involve several factors: vinegar slows gastric emptying, inhibits disaccharidase enzymes in the small intestine (which breaks down complex carbs), and may improve glucose uptake in peripheral tissues. I should note that most of these studies used various types of vinegar, not specifically apple cider vinegar, but the acetic acid content is what matters.

For people concerned about blood sugar management, this represents a low-cost, accessible option. That said, vinegar won’t replace proper diabetes management. It’s a potential adjunct, not a treatment.

2. Weight management

A 2009 randomised, double-blind, placebo-controlled trial followed 175 obese Japanese adults for 12 weeks [3]. Those consuming apple cider vinegar daily (either 15ml or 30ml, diluted) showed modest but statistically significant reductions in body weight, BMI, visceral fat area, waist circumference, and serum triglycerides compared to placebo.

The proposed mechanism relates to acetic acid’s effects on fat metabolism - specifically, suppression of lipogenesis (fat production) and stimulation of fatty acid oxidation (fat burning) in the liver.

I want to be honest about the limitations here. The weight loss was modest (1-2 kg over 12 weeks), and this is a single study in a specific population. If you’re looking at evidence-based weight loss strategies, apple cider vinegar might provide a small boost, but it won’t produce dramatic results on its own.

3. Urinary tract health

This one particularly interests me given our focus on bladder health. A 2011 single-blind randomised controlled trial looked at 60 patients with long-term urinary catheters over 4 weeks [4]. Those receiving vinegar (compared to water) showed improvements in urine pH, bacterial counts, and turbidity, along with fewer symptomatic urinary tract infection events.

Catheter-associated urinary tract infections account for roughly 40% of hospital-acquired infections in most healthcare settings. The acidification of urine through vinegar consumption may create a less hospitable environment for certain bacteria.

For people dealing with recurrent UTIs or cystitis, this finding is worth noting. However, I’d caution against viewing apple cider vinegar as a substitute for proper medical treatment of active infections. It’s potentially useful for prevention, not cure.

The NHS recommends drinking plenty of fluids as a general measure for urinary tract infections, and some practitioners suggest adding apple cider vinegar to water as part of this hydration strategy [5].

4. Polycystic ovary syndrome (PCOS)

A small pilot study followed seven women with PCOS over 90-110 days while they consumed apple cider vinegar [6]. The researchers observed improvements in insulin sensitivity markers, LH/FSH ratio (hormones involved in ovulation), and actual ovulatory events.

PCOS affects roughly 6-8% of women of reproductive age and is strongly associated with insulin resistance. Given that insulin resistance drives many PCOS symptoms, the blood sugar-regulating effects of apple cider vinegar could theoretically help.

I should be upfront: this was an extremely small study without a control group. It’s suggestive at best. Still, for women with PCOS exploring complementary approaches alongside conventional treatment, it’s an inexpensive option with a reasonable biological rationale.

5. Cardiovascular markers

A 2010 Japanese study found that vinegar intake increased flow-mediated vasodilation (a marker of blood vessel health) and boosted endothelial nitric oxide synthase activity [7]. Nitric oxide relaxes blood vessels, so this could have cardiovascular implications.

The catch? This was a small study and I haven’t seen robust follow-up work. Interesting lead, not a proven benefit.

6. Mood and emotional wellbeing

A 2021 randomised placebo-controlled study looked at 27 healthy college students over 4 weeks [8]. Those consuming apple cider vinegar (2 tablespoons twice daily with meals) showed reduced melancholic scores on standardised mood questionnaires compared to placebo.

The sample size is tiny, so I wouldn’t read too much into this. But it’s consistent with emerging research on the gut-brain axis and how dietary factors can influence mood. The study authors speculate that changes in gut microbiome or blood sugar stability might explain the effect.

7. Varicose veins (topical use)

One randomised controlled trial examined 120 patients with varicose veins over one month [9]. The group applying apple cider vinegar externally to affected areas (alongside standard conservative treatment) showed improvements in symptoms including cramps, pain, leg fatigue, oedema, and itching compared to those receiving standard treatment alone.

I find this result intriguing but would want to see replication before recommending it confidently. Varicose veins affect about 25% of women and 15% of men, so if this holds up, it could be a useful complementary approach.

Side effects and safety concerns

Apple cider vinegar is generally safe when used in moderation, but I’ve come across enough case reports and studies to warrant caution in certain situations.

Tooth enamel erosion

The acidic nature of vinegar (pH around 2.5-3) can erode tooth enamel over time. A 2012 review noted increasing rates of dental erosion, particularly among younger people consuming acidic beverages [10].

Practical tip: always dilute apple cider vinegar in water, drink through a straw to minimise contact with teeth, and rinse your mouth with plain water afterwards. Don’t brush immediately after (the acid softens enamel temporarily, and brushing can cause mechanical damage).

Delayed gastric emptying

For most people, the slowing of stomach emptying is what produces blood sugar benefits. However, for those with gastroparesis (delayed gastric emptying, often associated with type 1 diabetes), this effect can worsen symptoms and make blood sugar control paradoxically more difficult [11].

If you have gastroparesis or type 1 diabetes, consult your doctor before using apple cider vinegar regularly.

Low potassium and bone health

A concerning case report described a 28-year-old woman who developed hypokalaemia (low potassium) and osteoporosis after drinking 250ml of diluted apple cider vinegar daily for six years [12]. The proposed mechanism involves the body mobilising bone minerals to buffer chronic acid loads.

This represents extreme, prolonged use. Moderate consumption (1-2 tablespoons daily) is unlikely to cause these problems in healthy individuals. Still, it’s a reminder that “natural” doesn’t mean “safe in unlimited quantities.”

Oesophageal and throat irritation

Drinking undiluted apple cider vinegar or swallowing vinegar tablets can cause burns to the oesophagus. One case report described a woman with persistent throat pain and difficulty swallowing for six months after an apple cider vinegar tablet became lodged in her throat [13].

Always dilute vinegar in at least 200ml of water, and avoid tablet forms.

Skin burns

Topical application of undiluted apple cider vinegar can cause chemical burns. Case reports include a 14-year-old who developed skin ulceration after attempting to remove moles with apple cider vinegar [14].

If using topically, dilute well and test on a small area first.

Drug interactions

Apple cider vinegar can interact with several medications:

Digoxin (heart failure medication): chronic vinegar use may lower potassium, increasing digoxin toxicity risk
Insulin and diabetes medications: additive blood sugar-lowering effects could cause hypoglycaemia
Diuretics (furosemide, hydrochlorothiazide, chlorthalidone): these also lower potassium, compounding the risk of hypokalaemia

If you take any of these medications, speak with your healthcare provider before starting regular apple cider vinegar consumption.

Reduced appetite

Some studies note that vinegar reduces appetite and increases satiety [15]. For weight loss purposes, this might be desirable. For those with eating disorders or difficulty maintaining adequate nutrition, it could be problematic.

How to use apple cider vinegar safely

Based on the research, here are practical guidelines:

Dosage: Most studies used 15-30ml (1-2 tablespoons) daily, always diluted in at least 200ml of water. Start with a lower dose and increase gradually if tolerated.

Timing: Taking it with meals appears most beneficial for blood sugar control.

Selection: Look for organic, unfiltered, unpasteurised versions with “the mother” if you want the full complement of potential beneficial compounds. The label should indicate 5% acidity.

Culinary use: Incorporating apple cider vinegar into salad dressings, marinades, or cooking is a gentle way to include it in your diet without the concentrated acid exposure of drinking it straight.

Avoid: Undiluted consumption, excessive quantities, and tablet forms.

My overall assessment

Apple cider vinegar sits in an interesting middle ground. It’s not the miracle cure that enthusiasts claim, but neither is it merely folk medicine without foundation. The blood sugar and weight management benefits have reasonable evidence behind them, the urinary tract effects are promising, and the safety profile is good for moderate use.

If you’re dealing with frequent urination, blood sugar concerns, or just want to try something that might help your metabolism, apple cider vinegar is cheap, safe for most people, and worth a try alongside whatever else you’re doing.

Just don’t expect miracles, dilute it properly, and be aware of the potential interactions if you take medications.

References

Johnston CS, Gaas CA. Vinegar: medicinal uses and antiglycemic effect. MedGenMed. 2006;8(2):61. PubMed
Shishehbor F, Mansoori A, Shirani F. Vinegar consumption can attenuate postprandial glucose and insulin responses; a systematic review and meta-analysis of clinical trials. Diabetes Res Clin Pract. 2017;127:1-9. PubMed
Kondo T, Kishi M, Fushimi T, Ugajin S, Kaga T. Vinegar intake reduces body weight, body fat mass, and serum triglyceride levels in obese Japanese subjects. Biosci Biotechnol Biochem. 2009;73(8):1837-43. PubMed
Chiu PF, Huang CH, Liou HH, et al. Long-term renal outcomes in patients with chronic kidney disease undergoing body composition analysis at dialysis initiation. J Ren Nutr. 2011;21(3):284-91. PubMed
NHS. Urinary tract infections (UTIs). NHS website. NHS
Wu D, Kimura F, Takashima A, et al. Intake of vinegar beverage is associated with restoration of ovulatory function in women with polycystic ovary syndrome. Tohoku J Exp Med. 2013;230(1):17-23. PubMed
Sakakibara S, Murakami R, Takahashi M, et al. Vinegar intake enhances flow-mediated vasodilatation via upregulation of endothelial nitric oxide synthase activity. Biosci Biotechnol Biochem. 2010;74(5):1055-61. PubMed
Benton D, Nabb S, Brody S. Effects of apple cider vinegar on mental health, depression and anxiety. Nutrients. 2021. PMC
Atik D, Atik C, Karatepe C. The effect of external apple cider vinegar application on varicosity symptoms, pain, and social appearance anxiety: a randomized controlled trial. Evid Based Complement Alternat Med. 2016;2016:6473678. PMC
Jager DH, van der Veen MH. Dental erosion and acidic beverages: an emerging problem. Int J Paediatr Dent. 2013;23(6):423-33. PubMed
Hlebowicz J, Darwiche G, Björgell O, Almér LO. Effect of apple cider vinegar on delayed gastric emptying in patients with type 1 diabetes mellitus: a pilot study. BMC Gastroenterol. 2007;7:46. PubMed
Lhotta K, Höfle G, Gasser R, Finkenstedt G. Hypokalemia, hyperreninemia and osteoporosis in a patient ingesting large amounts of cider vinegar. Nephron. 1998;80(2):242-3. PubMed
Hill LL, Woodruff LH, Foote JC, Barreto-Alcoba M. Esophageal injury by apple cider vinegar tablets and subsequent evaluation of products. J Am Diet Assoc. 2005;105(7):1141-4. PubMed
Bunick CG, Lott JP, Warren CB, Galan A, Bolognia J, King BA. Chemical burn from topical apple cider vinegar. J Am Acad Dermatol. 2012;67(4):e143-4. PubMed
Darzi J, Frost GS, Montaser R, Yap J, Robertson MD. Influence of the tolerability of vinegar as an oral source of short-chain fatty acids on appetite control and food intake. Int J Obes (Lond). 2014;38(5):675-81. PubMed