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Head-to-head evidence comparison — which supplement is right for you?
Collagen and Raspberry Leaf are closely matched across evidence, studies, and safety.
Verdict
Likely helps
6 of 6 studies with measurable effects showed benefit.
Top outcomes
Verdict
Limited support
1 of 4 studies with measurable effects showed benefit.
Top outcomes
10-15g
Any time of day, With vitamin C for enhanced synthesis
Hydrolyzed collagen peptides (powder)
1-2g dried leaf as tea, 2-3 times daily
Between meals as tea, Divided throughout the day
Dried leaf tea
8-12 weeks
8-12 weeks
12 weeks
First week
2-3 cycles
Last trimester
Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis
The American Journal of Medicine (2025) · Meta analysis · n=1474
23 RCTs with 1474 participants
Effect of collagen supplementation on knee osteoarthritis: an updated systematic review and meta-analysis of randomised controlled trials
Clinical and experimental rheumatology (2025) · Meta analysis · n=870
The meta-analysis revealed an overall significant improvement of both function [MD, -6.46 (95% CI -9.52, -3.40); I2=75%; p=0.00001] and pain scores [MD, -13.63 (95% CI -20.67, -6.58); I2=88%; p=0.00001], favouring collagen supplementation.
Impact of Collagen Peptide Supplementation in Combination with Long-Term Physical Training on Strength, Musculotendinous Remodeling, Functional Recovery, and Body Composition in Healthy Adults: A Systematic Review with Meta-analysis
Sports medicine (Auckland, N.Z.) (2024) · Meta analysis · n=768
This systematic review and meta-analysis represents the first comprehensive investigation into the effects of long-term CP supplementation combined with regular physical training on various aspects of musculoskeletal health in adults.
Raspberry Leaves and Extracts-Molecular Mechanism of Action and Its Effectiveness on Human Cervical Ripening and the Induction of Labor
Nutrients (2023) · Systematic review
The majority of women apply raspberry leaves during pregnancy to induce and ease labor.
A Review on Berry Seeds-A Special Emphasis on Their Chemical Content and Health-Promoting Properties
Nutrients (2023) · Systematic review
Last search was conducted on 16.01.2023.
Phenolic Composition, Mineral Content, and Beneficial Bioactivities of Leaf Extracts from Black Currant (Ribes nigrum L.), Raspberry (Rubus idaeus), and Aronia (Aronia melanocarpa)
Nutrients (2020) · Systematic review
This was reviewed and discussed in this article.
Meta-analysis of 23 RCTs (n=1474) showed high-quality studies had less effect than industry-funded studies. Benefits include improved skin elasticity and hydration. Hydrolyzed collagen peptides preferred for bioavailability.
Based on single RCT (n=37) showing 25.6% glucose reduction when tea consumed with sucrose. Conservative estimate due to limited study population and single trial. Effect may be specific to tea preparation and timing with carbohydrate intake.
AI-estimated from published studies. Interpret as directional guidance.
Both Collagen and Raspberry Leaf are closely matched — the best choice depends on your specific health goals.
No known interactions between Collagen and Raspberry Leaf have been documented in our database. However, always consult a healthcare provider before combining supplements.