Grapefruit

Also known as: Citrus paradisi, grapefruit extract, grapefruit essential oil, grapefruit juice, nootkatone, GFJ

Evidence under review. — Not yet rated

Citrus fruit with drug interaction risks. Some evidence for aromatherapy and skin benefits. Not a proven supplement.

What it does

Grapefruit is a citrus fruit whose juice, peel, and essential oil are used in supplements and aromatherapy. Inhaled grapefruit essential oil showed some benefit for premenstrual symptoms in a...
Evidence quality

Evidence base hasn't been formally rated yet. See research below.
Clinical dose

No established dose

What the Science Says

Grapefruit is a citrus fruit whose juice, peel, and essential oil are used in supplements and aromatherapy. Inhaled grapefruit essential oil showed some benefit for premenstrual symptoms in a small clinical trial. A combination of grapefruit and rosemary extract showed preliminary photoprotective and anti-aging skin benefits in an early human study. Grapefruit's most well-documented effect is blocking a liver enzyme (CYP3A) that metabolizes many medications, which can dangerously raise drug levels in the blood.

What It Doesn't Do

Won't reliably burn fat or boost metabolism — no evidence from these studies. Not a proven treatment for any disease. Aromatherapy benefits don't translate to taking a grapefruit pill. Don't confuse flavoring in laxative products with any therapeutic grapefruit effect.

Evidence-Based Benefits

Inhaled grapefruit essential oil reduced premenstrual syndrome scores including anxiety, fatigue, and bloating.

Weak Evidence

Effective at: No established dose; inhalation 30 min 3x/day for 3 menstrual cycles used in study

Supporting studies (click to view on PubMed):

PMID 40312670

Oral grapefruit and rosemary extract combination showed early evidence of UV protection and anti-aging skin benefits.

Weak Evidence

Effective at: No established dose

Supporting studies (click to view on PubMed):

PMID 40362239

Grapefruit juice significantly raises blood levels of CYP3A-metabolized drugs like tacrolimus, creating serious interaction risks.

Moderate Evidence

Effective at: Even small amounts of grapefruit juice can trigger interactions

Supporting studies (click to view on PubMed):

PMID 41549771 PMID 42136239

Absorption & Bioavailability

Unknown for supplement forms. Grapefruit juice is well-known to inhibit intestinal CYP3A enzymes, which can dramatically increase absorption of certain drugs — this is a risk, not a benefit.

Red Flags to Watch For

Grapefruit juice and extract can dangerously increase blood levels of many prescription drugs including tacrolimus, statins, calcium channel blockers, and others — always check with your pharmacist
Most supplement products (1000+ on NIH DSLD) use grapefruit as a minor ingredient with no clinical evidence for the specific formulation
Aromatherapy studies used multi-oil blends, so grapefruit's individual contribution cannot be isolated
Early-phase nanocarrier studies involving grapefruit-derived vesicles are exploratory with very small sample sizes — far from proven therapies

Frequently Asked Questions

What does Grapefruit do?

Citrus fruit with drug interaction risks. Some evidence for aromatherapy and skin benefits. Not a proven supplement.

What is the effective dose of Grapefruit?

No established dose

Is Grapefruit safe?

Grapefruit juice and extract can dangerously increase blood levels of many prescription drugs including tacrolimus, statins, calcium channel blockers, and others — always check with your pharmacist

What doesn't Grapefruit do?

Won't reliably burn fat or boost metabolism — no evidence from these studies.

Research Sources

PubMed
NIH DSLD

This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-25