41 studies

Supplements

Supplementswell supported · human dataAdded 8 August 2026
Resveratrol fails to shift liver enzymes in pooled trials
Across 15 randomised trials with 714 participants, resveratrol supplementation produced no significant change in liver enzymes: ALT, AST, GGT, alkaline phosphatase and bilirubin all held statistically steady.
What it shows: Meta-analysis of 15 RCTs (714 adults); heterogeneity was high for some enzymes (I² up to 82.9%), and subgroup analyses hint that dose, duration and population status could matter, but the pooled result was null across the board.Meta-analysis · Int J Clin Pract
Full breakdown →Effects of resveratrol supplementation on liver enzymes: A systematic review and meta-analysis of randomised controlled trials. Int J Clin Pract 2021
Supplementswell supported · human dataAdded 8 August 2026
Zinc moves the needle on blood sugar in type 2 diabetes
Across 22 randomised trials in people with type 2 diabetes, zinc supplementation reduced HbA1c by 0.47 points and fasting blood sugar by 23.32 mg/dl, and improved cholesterol, triglycerides and blood pressure. It also increased body weight by an average of 1.00 kg.
What it shows: Dose-response meta-analysis of 22 RCTs (1,442 adults with type 2 diabetes); certainty rated moderate to high with no substantial publication bias, but the optimal form, dose and duration are unknown and weight rose slightly.Meta-analysis · Crit Rev Food Sci Nutr
Full breakdown →Insulin sensitivity explained Metabolic Fitness Index Effect of zinc supplementation in the management of type 2 diabetes: A grading of recommendations assessment, development, and evaluation-assessed, dose-response meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr 2024
Supplementspreliminary · human dataAdded 8 August 2026
Creatine helps older lifters, but only alongside the training
A systematic review of 17 randomised trials suggests creatine adds to gains in strength, functional capacity and lean mass in healthy older adults, but only as continuous daily low-dose supplementation combined with at least 12 weeks of resistance training, with effects more consistent in older women.
What it shows: Systematic review of 17 heterogeneous RCTs in healthy older adults without pooled effect sizes; no additive benefit was found for mental health outcomes, and optimal dosing and duration remain undetermined.Systematic review · J Geriatr Phys Ther
Full breakdown →Creatine monohydrate guide Creatine Calculator The Additive Effects of Creatine Supplementation and Exercise Training in an Aging Population: A Systematic Review of Randomized Controlled Trials. J Geriatr Phys Ther 2020
Supplementswell supported · human dataAdded 8 August 2026
Probiotics nudge athletes' immune markers in the right direction
Across pooled data from 69 randomised trials plus one further RCT (3,413 participants), probiotic supplementation in athletes reduced the pro-inflammatory marker TNF-α and increased secretory IgA and IFN-γ, while IL-6, IL-8 and IL-10 showed no significant change.
What it shows: Umbrella review and re-analysis of five meta-analyses plus one RCT (3,413 athletes); outcomes are blood and mucosal markers, not illness rates, and optimal strains and doses remain unresolved.Meta-analysis · PeerJ
Full breakdown →Effects of probiotic supplementation on immune and inflammatory markers in athletes: an umbrella review and re-analysis of published meta-analyses of randomised controlled trials. PeerJ 2026
Supplementswell supported · human dataAdded 8 August 2026
Creatine does nothing for endurance in trained athletes
Creatine monohydrate did not improve endurance performance in trained people across 13 placebo-controlled trials, with a trivial, non-significant pooled effect of -0.07.
What it shows: Meta-analysis of 13 placebo-controlled trials in trained populations only; endurance tests varied between studies; the finding does not contradict creatine's established benefit for short, high-intensity exercise.Meta-analysis · Sports Med
Full breakdown →Creatine monohydrate guide Creatine Calculator Effects of Creatine Monohydrate on Endurance Performance in a Trained Population: A Systematic Review and Meta-analysis. Sports Med 2023
Supplementspreliminary · human dataAdded 8 August 2026
Sesame may boost athletes' antioxidant defences: exercise does the rest
In semiprofessional athletes doing aerobic training, four small trials suggest sesame supplementation boosted antioxidant defences and lowered the oxidative-stress marker malondialdehyde; reductions in inflammatory cytokines appeared to come mainly from the exercise itself.
What it shows: Systematic review of just four RCTs (140 semiprofessional athletes, 4-10 weeks); outcomes were blood biomarkers only, with no direct performance or recovery measures, so replication and functional endpoints are needed.Systematic review · Nutr Health
Full breakdown →Recovery Readiness Index The emerging role of sesame supplementation with aerobic exercise in athlete recovery and immunomodulation: A systematic review of human trials. Nutr Health 2026
Supplementswell supported · human dataAdded 8 August 2026
Tart cherry trims one inflammation marker, and leaves the others alone
Outside of exercise settings, tart cherry lowered the inflammation marker C-reactive protein by an average of 0.55 mg/L across ten randomised trials, but had no significant effect on IL-6 or TNF-α.
What it shows: Meta-analysis of 10 non-exercise RCTs; the CRP reduction was modest, IL-6 showed no significant change, and TNF-α was assessed in only three studies, also with no significant effect.Meta-analysis · Complement Ther Med
Full breakdown →The beneficial effect of tart cherry on plasma levels of inflammatory mediators (not recovery after exercise): A systematic review and meta-analysis on randomized clinical trials. Complement Ther Med 2022
Supplementswell supported · human dataAdded 8 August 2026
Curcumin plus black-pepper extract shifts blood fats: except LDL
Across 16 randomised trials in 1038 adults, curcuminoids taken with piperine significantly lowered triglycerides and total cholesterol and modestly raised HDL cholesterol; LDL cholesterol did not fall significantly.
What it shows: Meta-analysis of 16 RCTs (1038 adults); effects were modest, the LDL-C change was non-significant, and benefits were most pronounced with longer supplementation and in people with dyslipidaemia, metabolic disorders or overweight.Meta-analysis · Lipids
Full breakdown →Heart Age Calculator Effects of Curcuminoids Plus Piperine Co-Supplementation on Serum Lipid Profile in Adults: A Systematic Review and Meta-Analysis of RCTs. Lipids 2026
Supplementswell supported · human dataAdded 8 August 2026
Supplement users were 2.74 times more likely to report doping
Across 26 cross-sectional studies of 13,296 athletes, doping was 2.74 times more prevalent among dietary supplement users (14.7%) than non-users (6.7%), and supplement users also reported stronger doping intentions and attitudes.
What it shows: All 26 included studies were cross-sectional, so the link is an association and cannot show supplement use causes doping; doping was self-reported and measurement of supplement use was inconsistent across studies.Meta-analysis · Int J Drug Policy
Full breakdown →Are dietary supplement users more likely to dope than non-users?: A systematic review and meta-analysis. Int J Drug Policy 2023
Supplementswell supported · human dataAdded 8 August 2026
Black seed supplements cooled inflammation markers in metabolic syndrome
A meta-analysis of 16 randomised controlled trials in 1033 people with metabolic syndrome and related disorders found that Nigella sativa (black seed) supplementation significantly reduced inflammatory markers, CRP, TNF-α and IL-6, and improved oxidative stress markers versus placebo.
What it shows: Meta-analysis of 16 RCTs (n=1033) in patients with metabolic syndrome and related disorders; outcomes are blood biomarkers, not disease events, and the authors themselves conclude only that intake 'could be associated' with improvement.Meta-analysis · Curr Pharm Biotechnol
Full breakdown →Metabolic syndrome explained Effect of Nigella sativa Intake on Oxidative Stress and Inflammation in Patients with Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Curr Pharm Biotechnol 2024
Supplementspreliminary · human dataAdded 8 August 2026
Early review found protein supplement evidence too thin to recommend
A systematic review of nine randomised trials in healthy people found lean-mass gains of 0.8 to 1.9 kg with protein supplementation during resistance training, but the longest trial lasted only 12 weeks. The authors concluded the evidence did not support recommending protein supplements for healthy individuals.
What it shows: Systematic review of only nine RCTs in healthy subjects, searched up to April 2009; only three studies reached level 3 evidence and the longest intervention was 12 weeks, so the conclusion reflects a thin, dated trial base rather than a definitive verdict.Systematic review · Arch Latinoam Nutr
Full breakdown →Whey protein guide Protein Intake Calculator [Effectivity in the use of protein supplements in resistance training: systematic review]. Arch Latinoam Nutr 2010
Supplementspreliminary · human dataAdded 6 August 2026
Pomegranate showed recovery gains in small trials
A systematic review of 11 studies in 176 athletes and physically active people reported that pomegranate supplementation improved whole-body strength, feelings of vitality, muscle fatigue and soreness, vessel diameter and blood flow, and antioxidant markers, with faster recovery of post-training muscle-damage markers. Doses ranged from 50 ml to 500 ml over 7 days to 2 months.
What it shows: Narrative systematic review of 11 studies published 2010-2018 with just 176 participants in total, 155 of them male; no meta-analysis was performed, and supplement form, dose (50 ml-500 ml) and duration (7 days-2 months) varied so widely that results cannot be pooled or a dose inferred.Systematic review · Int J Vitam Nutr Res
Full breakdown →DOMS explained Effect of pomegranate fruit supplementation on performance and various markers in athletes and active subjects: A systematic review. Int J Vitam Nutr Res 2021
Supplementspreliminary · human dataAdded 6 August 2026
Your caffeine boost may hinge on one gene
Across 19 randomised trials with 732 participants using caffeine doses of 2 to 9 mg/kg, performance benefits were most consistent in people carrying the CYP1A2 AA genotype, smaller in AC carriers, and null or even detrimental in those with the CC genotype, though the studies did not all agree.
What it shows: Systematic review of 19 RCTs in 732 athletes and physically active people published 2012-2024, with no meta-analysis and no consensus between studies; 84% of the included trials were rated as raising 'some concerns' for risk of bias and only two were low risk.Systematic review · Nutr Res
Full breakdown →Caffeine guide Caffeine Half-Life Calculator Influence of the CYP1A2 genotype on the exercise performance of physically active individuals under caffeine supplementation: a systematic review. Nutr Res 2025
Supplementswell supported · human dataAdded 6 August 2026
Moderate caffeine dose beat low dose in time trials
Pooling 48 randomised placebo-controlled trials (689 healthy adults), low caffeine doses of ≤3 mg·kg-1 shortened aerobic time-trial completion time (SMD -0.27), while moderate doses of 4-6 mg·kg-1 produced a larger and more consistent effect (SMD -0.52). No eligible trial reporting time-to-completion tested doses above 6 mg·kg-1.
What it shows: Meta-analysis of 48 randomised placebo-controlled trials in healthy adults aged 18-59 using acute oral anhydrous caffeine, but only 689 participants in total, effects pooled as standardised mean differences across varied time-trial protocols, and no trials of doses above 6 mg·kg-1 met the inclusion criteria, so the top of the dose range remains untested for this outcome.Meta-analysis · Nutrients
Full breakdown →Caffeine guide Caffeine Half-Life Calculator Dose-Response Effect of Oral Caffeine Use on Aerobic Exercise Performance: A Systematic Review and Meta-Analysis. Nutrients 2026
Supplementswell supported · human dataAdded 6 August 2026
BCAA supplements added little to resistance training
In a meta-analysis of 12 randomised trials (459 older adults with sarcopenia), adding branched-chain amino acid-rich supplements to resistance training improved only skeletal muscle index (SMD 0.337, p = 0.029). Grip strength, walking speed, chair-stand performance, SPPB score, knee extension strength, total lean mass and fat mass showed no significant advantage.
What it shows: Meta-analysis of 12 randomised trials with only 459 participants in total, all older adults with sarcopenia; the one positive outcome had a confidence interval reaching close to zero and several functional measures pointed in inconsistent directions, so this cannot be read across to younger or healthy trainees.Meta-analysis · Arch Gerontol Geriatr
Full breakdown →Sarcopenia explained Protein Intake Calculator Effects of branched-chain amino acid-rich nutritional supplements combined with resistance training on body composition and body function in older patients with sarcopenia. Arch Gerontol Geriatr 2026
Supplementswell supported · human dataAdded 6 August 2026
HMB added nothing on top of resistance training
Across 13 randomised trials of 561 adults aged 50 and over, adding HMB to resistance training produced no significant benefit for fat mass (SMD 0.24), muscle mass (SMD 0.05) or muscle strength (SMD 0.04). The authors concluded it cannot be recommended as a routine adjunct for people able to do structured exercise.
What it shows: Meta-analysis of 13 randomised trials totalling 561 adults aged 50 and over; heterogeneity was high for the strength outcomes and trial durations and doses varied, and the findings say nothing about people unable to train or about younger lifters.Meta-analysis · Age Ageing
Full breakdown →Sarcopenia explained Protein Intake Calculator Efficacy of HMB supplementation as an adjunct to resistance training in older adults: a comprehensive meta-analysis. Age Ageing 2026
Supplementspreliminary · human dataAdded 6 August 2026
Creatine's edge may not carry to elite athletes
A critical review of the creatine literature concluded that the supplement's performance benefits have generally been shown in untrained people doing several exercise bouts under laboratory conditions, while the limited data available on highly trained athletes performing single competition-like tasks showed no benefit. The authors judged that widespread creatine use to improve competition performance was not justified on that evidence, though repeated-effort sports remained a plausible unconfirmed case.
What it shows: A narrative critical review from 1997, not a modern pooled analysis: it rests on a small body of studies in highly trained athletes, reports no effect sizes, and says nothing about creatine's use during training blocks or in non-athletes.Meta-analysis · Int J Sports Med
Full breakdown →Creatine monohydrate guide Creatine Calculator Creatine supplementation as an ergogenic aid for sports performance in highly trained athletes: a critical review. Int J Sports Med 1997
Supplementswell supported · human dataAdded 6 August 2026
Probiotics nudged spine bone density, not bone markers
Pooling randomised trials, probiotic supplementation produced small increases in lumbar spine areal bone mineral density (+0.010) and hip aBMD (+0.022 g/cm2), with no significant effect on femoral neck density or on the bone turnover markers P1NP and CTX. Most included trials were in postmenopausal women.
What it shows: Systematic review and meta-analysis of randomised trials (16 comparisons for lumbar spine, 9 for hip, 7 for femoral neck), mostly in postmenopausal women, with moderate-to-high heterogeneity throughout; the hip effect became non-significant when key trials were removed, and no fracture outcomes were pooled.Meta-analysis · Osteoporos Int
Full breakdown →Probiotic Supplementation and Bone Health Parameters in Adults: A Systematic Review and Meta-Analysis. Osteoporos Int 2026
Supplementswell supported · human dataAdded 6 August 2026
Vitamin D's cold-fighting effect shrinks in big trials
A critical review with meta-analysis found that vitamin D's apparent protection against acute respiratory infections was confined to small trials: the summary odds ratio was 0.69 in trials of 25 to fewer than 248 patients but 0.98 in trials of 248 to 16,000 patients (interaction p = 0.0001), with strong evidence of publication bias.
What it shows: A meta-analysis of previously published randomised trials, not new experimental data; the acute respiratory infection trials were re-analysed from an earlier pooled dataset, and the analysis splits trials by size, which can be confounded by differences in populations, doses and outcome definitions. It shows the benefit signal is fragile, not that vitamin D is useless for people who are deficient.Meta-analysis · PLoS One
Full breakdown →Vitamin D, acute respiratory infections, and Covid-19: The curse of small-size randomised trials. A critical review with meta-analysis of randomised trials. PLoS One 2025
Supplementspreliminary · human dataAdded 1 August 2026
Ketone drink raised ketones but not race performance
Adding 1,3-butanediol to a carbohydrate drink roughly doubled circulating ketones in male athletes long adapted to a ketogenic diet, but time-trial performance was no better than carbohydrate alone. Lactate, substrate oxidation, oxygen consumption, perceived exertion and heart rate were also unchanged.
What it shows: A counterbalanced crossover trial in just 9 recreationally active men with at least a year of ketogenic adherence; the authors stress this is too small to prove no effect, only that none was detectable here.RCT · Nutrients
Full breakdown →Acute 1,3-Butanediol Co-Ingestion with Carbohydrate Does Not Improve Endurance Performance in Chronically Ketogenic Male Athletes. Nutrients 2026
Supplementspreliminary · human dataAdded 30 July 2026
CoQ10 beat taurine on muscle-damage markers
In a 14-day randomised trial in under-19 footballers, CoQ10 (300 mg/day) lowered markers of oxidative stress, muscle damage and cortisol more than taurine, while taurine raised the anti-inflammatory marker IL-10 more; both blunted the drop in immune markers. These were blood markers only, with eight players per group.
What it shows: Randomised, double-blind, placebo-controlled but very small: 24 male under-19 soccer players, only 8 per group, 14 days, and outcomes were circulating biomarkers with no performance or recovery measures. The authors call the findings preliminary and pending confirmation in larger trials.RCT · Nutrients
Full breakdown →Cortisol explained Recovery Readiness Index Practical Nutritional Strategies to Attenuate Physiological Stress in Adolescent Soccer Players: A Comparative Trial of CoQ10 and Taurine. Nutrients 2026
Supplementswell supported · human dataAdded 30 July 2026
Beetroot juice lifts VO2max, but mostly in amateurs
Across 38 placebo-controlled trials in 703 healthy adults, beetroot juice produced a small but significant improvement in VO2max/VO2peak (SMD 0.24). The gain was clearer in recreationally active people (SMD 0.38) and not clearly demonstrated in highly trained athletes (SMD 0.07).
What it shows: Meta-analysis of 38 randomised and crossover trials, 703 healthy adults; effects are small, funnel-plot asymmetry suggested small-study bias and the pooled estimate shrank to 0.19 after adjustment. Certainty rated moderate.Systematic review · Front Nutr
Full breakdown →VO₂max explained VO2max Calculator Effects of beetroot juice supplementation on maximal oxygen uptake during aerobic exercise: a systematic review and meta-analysis. Front Nutr 2026
Supplementspreliminary · human dataAdded 30 July 2026
Beetroot shot nudged leg torque, but not at top speed
In a crossover trial, 13 physically active men produced greater peak torque and relative peak power on isokinetic knee extension at 60 and 180 degrees per second after beetroot juice containing 800 mg of nitrate than after placebo. Nothing changed during the faster 240 degrees per second fatigue protocol, and muscle EMG and post-exercise lactate were unchanged.
What it shows: One small randomised, double-blind, placebo-controlled crossover trial in 13 physically active young men using isokinetic dynamometry, not free-weight lifting; mechanisms unexplained and replication needed.RCT · Nutrients
Full breakdown →Creatine monohydrate guide One-Rep Max Calculator Effects of Acute Dietary Nitrate Supplementation on Selected Isokinetic Performance Variables in Physically Active Men. Nutrients 2026
Supplementspreliminary · human dataAdded 29 July 2026
Omega-3 moved lipids and blood pressure, not kidney function
Genetically predicted higher plasma omega-3 levels were associated with a lower risk of diabetic kidney disease (odds ratio 0.869), while omega-6 showed no significant association; a paired meta-analysis of 12 randomised trials (474 participants) found omega-3 supplementation lowered triglycerides, systolic blood pressure and a kidney injury marker, but did not improve albumin-to-creatinine ratio or estimated glomerular filtration rate.
What it shows: Genetic (Mendelian randomisation) analysis plus a meta-analysis of 12 small trials totalling only 474 participants in people with diabetic kidney disease; mediation findings were nominally significant only, and hard kidney-function outcomes did not shift.Study · FASEB J
Full breakdown →Metabolic Fitness Index The Impact of Omega Fatty Acids on DKD: A Multimodal Study Integrating Mendelian Randomization, Proteomic Mediation Analysis, and Meta-Analysis. FASEB J 2026

Back to the full archive · this week’s studies