Supplements
The supplement aisle is mostly noise. We score products on efficacy, third-party testing, value, and label honesty — then tell you which ones earn the spend.
No direct evidence: No published human trials have tested cinnamon supplementation specifically for strength gains or resistance-training outcomes. Indirect mechanisms exist but are speculative: Cinnamon's insulin-sensi…
Weak direct evidence: No robust clinical trials show that alpha-lipoic acid (ALA) meaningfully increases muscle strength or mass in healthy, resistance-training adults. Indirect mechanisms exist — ALA influences insulin…
There is currently no meaningful clinical evidence that berberine improves strength gains in humans; it has not been studied as a resistance-training supplement. Berberine's primary researched benefits are metabolic — b…
The direct evidence linking probiotic supplementation to meaningful strength gains in humans is limited and inconsistent — this is not a well-supported use case yet. A small number of trials suggest probiotics may modes…
Very limited direct evidence: No well-powered clinical trials have tested inulin supplementation specifically for strength gains in humans. Indirect pathways exist but are speculative: Inulin may support gut health and …
No direct evidence: No peer-reviewed studies have tested psyllium husk as a strength-building supplement; the pairing has essentially no research base. Indirect pathways exist but are weak: Psyllium may support gut heal…
Iron deficiency — not just anaemia — can meaningfully limit strength and endurance performance , but correcting a deficiency is very different from supplementing when levels are already normal. In people who are iron-de…
Zinc is essential for testosterone production and muscle protein synthesis , but supplementing it only meaningfully helps people who are actually deficient — a group that includes some athletes and vegetarians. Evidence…
Very limited direct evidence: No well-powered human trials have tested vitamin K2 specifically for muscle strength gains in healthy adults. Mechanistic plausibility exists — K2 activates proteins involved in muscle and …
Vitamin D3 may support muscle strength, particularly in people who are deficient, but evidence in already-sufficient individuals is weak and inconsistent. The most reliable signal comes from older adults and deficient p…
Fish oil has modest, preliminary evidence for supporting muscle protein synthesis and reducing exercise-induced inflammation, but it has not been shown to reliably increase strength in healthy, well-nourished adults. Mo…
Caffeine has reasonably consistent evidence for improving acute strength performance — meaning it can help you lift more in a given session — but the effect on long-term strength gains is less well established. The most…
Beta-alanine is well-supported for improving muscular endurance, but its evidence for pure strength gains (1-rep max, peak force) is weak and inconsistent. Where strength benefits do appear, they tend to show up in high…
Strong evidence: Whey protein supplementation, combined with resistance training, modestly but consistently increases muscle strength and lean mass compared to training alone or carbohydrate controls. Effect size matter…
Strong evidence: Creatine monohydrate is one of the most researched ergogenic supplements, with consistent data showing modest but real improvements in strength and power output during resistance training. How big an ef…
Very limited direct evidence: No well-powered human trials have tested l-theanine specifically for muscle strength gains, making this a low-evidence pairing. Indirect mechanisms exist but are weak: L-theanine may improv…
No meaningful evidence links valerian root to muscle strength gains in humans — this is not an established use of the herb. Valerian is a well-studied sedative and sleep aid; any indirect benefit to recovery would come …
Several small randomized controlled trials suggest ashwagandha modestly improves muscle strength and recovery compared with placebo, but the overall evidence base is limited in size and quality. The most studied dose is…
Weak evidence overall: Melatonin has not been meaningfully studied as a muscle-building supplement; the few trials that exist are small, short, and measure indirect markers rather than actual strength gains. Indirect pa…
Magnesium plays a genuine role in muscle function and protein synthesis, but the direct evidence that supplementing it increases strength gains in already-replete adults is thin and mixed. People who are actually defici…
Very limited evidence: GABA supplementation has not been meaningfully studied as a muscle-growth agent in healthy exercising adults, and no strong clinical trials support its use for this purpose. One small signal: A si…
No direct evidence: No peer-reviewed studies have tested 5-HTP specifically for muscle growth or hypertrophy in humans. Indirect pathways exist but are weak: 5-HTP raises serotonin, which may influence sleep and appetit…
Weak direct evidence: No well-powered human trials have shown glycine supplementation meaningfully increases muscle mass on its own. Plausible but indirect mechanisms: Glycine is a component of creatine and collagen, bo…
NAD precursors (primarily NMN and NR) support cellular energy metabolism, but direct evidence for meaningful muscle growth in healthy adults is thin and mostly preclinical. Animal studies show promising effects on muscl…
Animal and early cell studies suggest ginseng compounds (ginsenosides) may support muscle protein synthesis and reduce exercise-induced inflammation, but human evidence is limited and inconsistent. A small number of ran…
Very limited direct evidence: No robust human clinical trials have tested rhodiola rosea specifically for muscle growth (hypertrophy) as a primary outcome. Indirect mechanisms exist but are unproven in this context: Rho…
Weak evidence overall: Green tea extract has not been shown to directly stimulate muscle growth (hypertrophy) in humans in well-powered clinical trials. Antioxidant effect is real, but its training relevance is debated:…
Curcumin shows modest evidence for reducing exercise-induced muscle damage and soreness , but direct evidence that it increases muscle mass or strength is thin. Most human trials have studied recovery and inflammation m…
Very limited direct evidence: No human clinical trials have tested cinnamon specifically for muscle growth or hypertrophy as a primary outcome. Indirect mechanisms exist but are speculative: Cinnamon's effects on insuli…
No direct evidence: Alpha-lipoic acid (ALA) has not been shown in human clinical trials to meaningfully increase muscle mass or strength on its own. Indirect mechanisms exist but are weak: ALA's antioxidant and insulin-…