Vitamin B2 for Elevated Blood Pressure

The short answer: vitamin B2 (riboflavin) is not a general blood pressure supplement. Its evidence for high blood pressure comes from people with a specific genotype. In treated hypertensive adults with the MTHFR 677TT genotype, 1.6 mg a day for 16 weeks lowered systolic pressure by 5.6 mmHg more than placebo (Wilson 2013), and in TT patients with heart disease mean pressure fell from 144/87 to 131/80 mmHg, with no response in the other genotypes (Horigan 2010).

Outside that group the trials are thin and unconvincing. A 2025 Cochrane review pooled four trials and called the effect of riboflavin on blood pressure very uncertain (Bradbury 2025), and a 2024 network meta-analysis of vitamins in essential hypertension found no significant effect for riboflavin (Qi 2024). We rate it mixed: a plausible, cheap add-on if you know you're TT, and not worth taking for blood pressure otherwise.

Riboflavin is the precursor of FAD, the cofactor for the folate-processing enzyme MTHFR. People with the TT genotype have reduced MTHFR activity because the variant enzyme loses its riboflavin cofactor too easily (McNulty 2006). Better riboflavin status is thought to keep the cofactor bound and restore some of that activity.

The genotype matters for blood pressure in its own right. In 6,076 Irish adults, TT carriers aged 18-70 had higher odds of hypertension (OR 1.42), and TT combined with deficient riboflavin status tripled the odds compared with CC carriers with normal status (Ward 2020). Among healthy adults screened for MTHFR genotype, both TT and low riboflavin status were independent determinants of hypertension, and TT women had systolic pressure almost 10 mmHg higher than non-TT women (Rooney 2022).

How a better-working MTHFR lowers blood pressure is not known. The Irish data linked the genotype to higher blood pressure independently of homocysteine (Ward 2020). In 80 TT adults, riboflavin changed DNA methylation at a few blood-pressure-related genes, some only in women, but the study didn't connect those changes to blood pressure (Amenyah 2021).

So the mechanism explains why only TT carriers might respond. It doesn't predict that riboflavin helps people whose high blood pressure has other causes, and none of these findings shows fewer strokes or heart attacks.

All three blood pressure trials used 1.6 mg of riboflavin a day for 16 weeks, taken with participants' usual antihypertensive drugs (Horigan 2010; Wilson 2012; Wilson 2013). That is a nutritional dose, a little above the adult RDA of 1.3 mg for men and 1.1 mg for women (NIH ODS).

No trial has tested higher doses for blood pressure, so there's no reason to take the 400 mg used for migraine prevention for this purpose. More is not obviously better: in a US survey, the highest total intakes of riboflavin and other B vitamins went with higher odds of hypertension (Ma 2026), though a survey can't show cause.

Horigan 2010 screened 404 patients with premature cardiovascular disease for MTHFR genotype and enrolled 197; they were randomised within genotype groups to riboflavin 1.6 mg a day or placebo for 16 weeks, and 181 completed. Only 37% of TT patients on medication had reached target blood pressure, against 59% of CT and 64% of CC patients. Riboflavin lowered mean pressure in TT patients from 144/87 to 131/80 mmHg, with no response in the other genotypes.

Four years later, 31 TT patients from that trial repeated the intervention with treatments reversed. Across both rounds riboflavin lowered systolic pressure by 9.2 mmHg and diastolic by 6.0 mmHg (Wilson 2012). Wilson 2013 then screened 1,427 hypertensive patients, found 157 with TT and randomised 91: over 16 weeks, systolic pressure fell 5.6 mmHg more than with placebo (P = 0.033), while diastolic pressure didn't change significantly. More than 60% of them hadn't reached goal on multiple drugs. The group's review puts the systolic effect at 6 to 13 mmHg (McNulty 2017).

The 2025 Cochrane review, run by researchers outside the Ulster group, included four trials with 374 participants. The pooled effect on systolic pressure was -1.94 mmHg (95% CI -5.74 to 1.86) and on diastolic pressure -3.03 mmHg (95% CI -5.97 to -0.09), both very low-certainty evidence, with three trials at high risk of bias (Bradbury 2025). It analysed genotype as a subgroup, but there are too few trials for firm conclusions either way.

A 2024 network meta-analysis of 23 placebo-controlled vitamin trials (2,218 people with essential hypertension) found that only vitamin E lowered systolic pressure significantly; riboflavin, vitamin C, vitamin D and folic acid did not, and none changed diastolic or 24-hour pressure (Qi 2024).

In 12,245 Chinese adults followed in the China Health and Nutrition Survey, 35.1% developed hypertension. Risk was higher only in the lowest quarter of riboflavin intake; the other three quarters had a 26% lower risk (HR 0.74) (Liu 2020). In the Jiangsu Nutrition Study, where 97.2% of 1,227 adults ate less riboflavin than they need, higher intake went with a smaller rise in systolic pressure over 5 years (Shi 2014). A case-control study of 400 older adults in northern China found lower blood riboflavin in those with hypertension (Zhang 2025).

These studies can't separate riboflavin from overall diet quality. And in 17,484 US adults, the highest total riboflavin intake, including supplements, went with higher odds of hypertension (OR 1.23), though lower odds of a wide pulse pressure (Ma 2026). The consistent message is to avoid a low intake, not to megadose.

At 1.6 mg a day riboflavin is a nutrient-level dose. NIH notes that no adverse effects have been reported from high intakes from food or supplements, including 400 mg a day for at least 3 months, so no upper limit has been set, though the Food and Nutrition Board urges caution with excessive amounts (NIH ODS). The Cochrane review found riboflavin may make little to no difference to adverse events (Bradbury 2025). Bright yellow urine is expected and harmless.

The real risk is opportunity cost. A few mmHg in a genetic subgroup is no substitute for proven treatment. NHLBI notes that many people need two or more medicines to manage high blood pressure, and that lifestyle changes should continue alongside them (NHLBI).

The measures with the best evidence are the ones in standard care. NHLBI recommends a heart-healthy eating plan such as DASH, noting that DASH combined with a low-salt diet can be as effective as medicines; limiting alcohol; regular physical activity, even 10 minutes of walking a day; losing 3-5% of body weight if you're overweight; quitting smoking; managing stress; and 7-9 hours of sleep (NHLBI). When lifestyle changes aren't enough, medicines such as ACE inhibitors, angiotensin receptor blockers, calcium channel blockers and thiazide diuretics are the next step.

Among supplements, potassium for high blood pressure and garlic extract have stronger evidence than riboflavin.

Riboflavin is not known to have any clinically relevant interactions with medications (NIH ODS), and in the trials it was taken alongside a range of antihypertensive drugs. The interplay worth knowing is with diet: in the Chinese cohort, the link between riboflavin intake and lower hypertension risk was strongest in people with a lower sodium-to-potassium ratio (Liu 2020).

For TT carriers, riboflavin works on the same enzyme as folate; the genetics are covered on our vitamin B2 for MTHFR page.