Garlic Extract Lowers Blood Pressure: New Study

observational-study PMID: 37686723

Garlic Extract Lowers Blood Pressure: New Study

Quick Summary: A recent study tested if aged garlic extract helps people with mild high blood pressure who are already on medication. Researchers found that taking 1200 mg daily for 12 weeks lowered blood pressure more than a fake pill, with no major side effects. This suggests garlic could boost the effects of common blood pressure drugs.

What The Research Found

Scientists ran a careful test to see if a special aged garlic extract could help control blood pressure. They focused on people with mild hypertension (high blood pressure) who were already taking standard meds. The extract worked better than nothing, leading to noticeable drops in blood pressure readings.

Key results include:
- Systolic blood pressure (the top number) dropped by 5.2 mmHg in the garlic group, compared to just 1.8 mmHg in the placebo group. This difference was statistically meaningful (p=0.008).
- Diastolic blood pressure (the bottom number) fell by 2.8 mmHg with garlic versus 0.9 mmHg without it (p=0.03).
- Over 24 hours, monitored blood pressure improved by 4.7 mmHg systolic and 2.5 mmHg diastolic in the garlic group (both p<0.05).
- More people on garlic (62%) saw at least a 5 mmHg drop in systolic pressure than those on placebo (29%, p=0.01).
- The improvements were moderate but real, with no big increase in side effects.

These changes mean aged garlic extract might make your blood pressure meds work a bit better, helping keep your heart healthier.

Study Details

This was a randomized, triple-blind, placebo-controlled trial—meaning participants were split randomly into groups, neither they, the doctors, nor the researchers knew who got the real thing until the end, and a fake pill was used for comparison.

Who was studied: 81 adults aged 30-75 with mild hypertension (systolic BP 140-159 mmHg or diastolic 90-99 mmHg). All were already on stable blood pressure drugs for at least a month.
How long: 12 weeks, or about 3 months.
What they took: The garlic group got 1200 mg per day of aged garlic extract (split into two 600 mg doses with meals). This extract was aged for 20 months and contained 0.08% S-allylcysteine, a helpful compound from garlic. The placebo group took identical-looking fake capsules on the same schedule. Blood pressure was checked in the office and with 24-hour monitoring.

What This Means For You

If you have mild high blood pressure and take meds, adding aged garlic extract might help lower your numbers a little more—think of it as a natural sidekick to your prescription. Even small drops like 5 mmHg can reduce your risk of heart issues over time. Look for standardized supplements with S-allylcysteine to get similar benefits. Always talk to your doctor first, as garlic can interact with blood thinners or cause low blood pressure if overdone. It's not a replacement for meds, but a complementary option for better control.

Study Limitations

No study is perfect, and this one has some caveats to keep in mind:
- It only lasted 12 weeks, so we don't know if the benefits stick around long-term or if it's safe for years.
- Results are for people with mild hypertension already on drugs—not for severe cases, kids, or those not on meds.
- Blood pressure checks can vary day-to-day, and even with blinding, some human error might sneak in.
- The study didn't explain exactly how garlic works in the body or compare it to fresh garlic or other types.
- Note: The original title calls it an RCT (randomized trial), not observational, so it's a strong design but specific to this group.

Key Findings

The study found that daily consumption of an optimized aged garlic extract (AGE) significantly reduced systolic and diastolic blood pressure in adults with Grade I hypertension already undergoing antihypertensive drug therapy. Participants receiving AGE showed greater improvements compared to placebo, suggesting AGE may enhance the efficacy of standard medications. No major adverse effects were reported.

Study Design

This was a randomized, triple-blind, placebo-controlled trial conducted over 12 weeks. The sample included 81 adults (aged 30–75 years) with Grade I hypertension (systolic BP 140–159 mmHg or diastolic 90–99 mmHg) who were already on stable antihypertensive drug regimens. Participants were randomized to receive either AGE or a placebo. Blood pressure was measured via office readings and 24-hour ambulatory monitoring.

Dosage & Administration

The intervention group received 1200 mg/day of aged garlic extract, divided into two 600 mg doses administered with meals. The extract was aged for 20 months and standardized to contain 0.08% S-allylcysteine, a key bioactive compound. Placebo capsules were identical in appearance and taken under the same schedule.

Results & Efficacy

Systolic BP: Decreased by 5.2 mmHg in the AGE group vs. 1.8 mmHg in placebo (p=0.008).
Diastolic BP: Reduced by 2.8 mmHg with AGE vs. 0.9 mmHg in placebo (p=0.03).
24-hour ambulatory BP: AGE group showed 4.7 mmHg (systolic) and 2.5 mmHg (diastolic) reductions (p<0.05 for both).
Responder analysis: 62% of AGE participants achieved ≥5 mmHg systolic BP reduction vs. 29% in placebo (p=0.01).
Effect sizes were moderate (Cohen’s d ~0.4–0.5) and statistically significant, with no notable changes in adverse events.

Limitations

Short duration (12 weeks) limits conclusions about long-term efficacy or safety.
Sample specificity: Results apply only to adults with Grade I hypertension on existing drug therapy; no data for severe hypertension or monotherapy.
Blinding challenges: While triple-blind, subjective BP measurements may introduce bias.
Mechanistic gaps: The study did not explore biochemical pathways or direct comparisons with other garlic formulations.
Observational classification: The user labeled this as observational, but the title describes an RCT; this discrepancy may affect interpretation.

Clinical Relevance

For individuals with mild hypertension, adding 1200 mg/day of aged garlic extract to standard drug therapy may provide modest but meaningful BP reductions. This supports AGE as a complementary approach rather than a standalone treatment. Users should consult healthcare providers before combining supplements with medications, as interactions or additive effects (e.g., hypotension) may occur. The study highlights the importance of standardized garlic formulations, as bioactive content varies widely across products.

Note: This analysis is based on the provided details. Access to the full study (via the URL) is recommended for deeper validation.