Red Raspberry Leaf
Also known as: Rubus idaeus, RRL, raspberry leaf tea, red raspberry leaf extract
Effective Dosage
No established dose
What the Science Says
Red raspberry leaf comes from the leaves of the raspberry plant and has been used traditionally, especially around pregnancy and labor. In lab studies, it showed some ability to inhibit an enzyme involved in fat absorption (DGAT1), but this effect did not translate into meaningful results in humans in the one clinical trial that tested it. Animal studies suggest it may have some effect on uterine muscle activity, though results were inconsistent depending on the preparation used.
What It Doesn't Do
Won't detox your body — the one human trial testing it as part of a detox blend found zero benefit. No proven effect on labor or birth outcomes in humans. Not shown to improve body composition, gut symptoms, or blood markers. No evidence it supports fertility.
Evidence-Based Benefits
In vitro screening identified red raspberry leaf extract as a potential inhibitor of intestinal DGAT1 enzyme activity (IC50 = 5.6 μg/mL), but this did not translate to significant clinical benefit in a 7-day human trial where only grape extract reduced postprandial triglycerides (PMID: 26246845). In vitro rat uterine studies showed variable and inconsistent effects on uterine contractility depending on preparation type and pregnancy status, with no clear augmentation of labor contractions (PMID: 20220111). Maternal exposure in rats altered cytochrome P450 enzyme activity in female offspring, suggesting potential pharmacokinetic interactions (PMID: 21115944).
Weak EvidenceEffective at: No established dose
Source: auto-research
Absorption & Bioavailability
Unknown — no human pharmacokinetic data provided in the available studies
Red Flags to Watch For
- Rated 'likely unsafe in pregnancy' without direct medical supervision by the Natural Medicines Interaction Checker — especially concerning given its heavy marketing to pregnant women
- Animal research suggests maternal use may permanently alter liver enzyme (CYP450) activity in female offspring, raising developmental safety concerns
- Frequently sold in multi-ingredient 'detox' blends where it has never been individually tested in humans
- Uterine effects in animal studies were inconsistent and preparation-dependent — tea, capsule, and extract behaved differently, making dosing unpredictable
- Over 1,000 registered supplement products contain this ingredient despite almost no standalone human clinical evidence
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: 2026-04-06