A systematic review conducted by Paultre et al. (2021) evaluated ten studies investigating the effects of curcumin on pain and physical function in individuals with knee osteoarthritis. All ten studies reported significant improvements in pain and functional outcomes following curcumin supplementation.

Similarly, a systematic review and meta-analysis by Liu et al. (2018) assessing dietary supplements for osteoarthritis concluded that curcumin produced clinically meaningful improvements in pain and physical function in individuals with osteoarthritis.

Curcumin has demonstrated potent anti-inflammatory properties, with some studies suggesting comparable activity to non-steroidal anti-inflammatory drugs (NSAIDs) in certain conditions.

Mechanistically, curcumin influences multiple inflammatory pathways. It has been shown to modulate NF-κB activity and interact with key inflammatory mediators including interleukins, phospholipase A2, 5-lipoxygenase, and cyclooxygenase-2 (COX-2) enzymes.

These actions contribute to its ability to help regulate inflammatory processes within the body.

The systematic review by Paultre et al. (2021) compared curcumin supplementation with both placebo and conventional NSAIDs in individuals experiencing knee osteoarthritis pain.

Across all ten studies included in the review, curcumin supplementation resulted in significant reductions in pain compared with placebo. When compared directly with NSAIDs, the degree of pain reduction was similar in several trials.

The authors suggested that curcumin may be a useful alternative for individuals unable to tolerate NSAIDs due to gastrointestinal side effects or stomach lining irritation.

Further systematic analysis by Liu et al. (2018) also demonstrated a statistically significant short-term analgesic effect of Curcuma longa extract.

Curcumin possesses several structural features responsible for its antioxidant activity, including phenolic groups, diketone structures, and conjugated double bonds.

Research has demonstrated that curcumin can inhibit lipid peroxidation, while also neutralising reactive oxygen species (ROS) and reactive nitrogen species (RNS) associated with oxidative stress and cellular damage.

A study by DiSilvestro et al. (2012) found that supplementation with curcumin increased the free-radical scavenging capacity of saliva, suggesting a direct antioxidant effect. The study also observed increased activity of the antioxidant enzyme catalase, indicating additional indirect antioxidant mechanisms.

Evidence suggests that curcumin may support healthy lipid metabolism.

A systematic review by Farzaei et al. (2018) reported that curcumin supplementation (approximately 500 mg per day) was associated with reductions in total cholesterol and LDL cholesterol, while also increasing HDL cholesterol levels.

In a clinical study involving healthy middle-aged adults, 80 mg of curcumin daily was shown to significantly reduce plasma triglycerides compared with placebo.

Curcumin has demonstrated hepatoprotective properties, meaning it may support and protect liver function.

The systematic review by Farzaei et al. (2018) examined curcumin supplementation in liver disease and identified multiple mechanisms by which curcumin may support liver health. A key mechanism is the reduction of oxidative stress within liver tissue, which plays a significant role in liver damage.

Additionally, DiSilvestro et al. (2012) observed that supplementation with 80 mg of curcumin daily reduced ALT (alanine aminotransferase), a marker of liver injury, suggesting a potential supportive effect for maintaining liver health.

Curcumin may support digestive comfort by helping regulate inflammatory processes in the gastrointestinal tract.

A meta-analysis conducted by Ng et al. (2018) evaluated the clinical use of curcumin in individuals with irritable bowel syndrome (IBS). The analysis found that curcumin demonstrated positive effects on IBS symptoms, although the results did not reach strong statistical significance compared with placebo.

The authors suggested that curcumin’s ability to reduce intestinal inflammation and discomfort may contribute to improvements in digestive symptoms.

A systematic review and meta-analysis by Akbari et al. (2019) evaluated the effects of curcumin supplementation on metabolic health outcomes in individuals with metabolic syndrome and related conditions.

The analysis included 18 studies (21 clinical trials) using curcumin in either powder or extract form.

The results demonstrated that curcumin supplementation was associated with significant reductions in:

• Body weight
• Body mass index (BMI)
• Waist circumference
• Leptin levels

Additionally, curcumin supplementation significantly increased adiponectin levels, a hormone involved in regulating glucose levels and fatty acid metabolism. These changes are thought to occur through modulation of biochemical pathways involved in fat metabolism and adipose tissue regulation.

Multiple clinical studies have investigated Boswellia serrata for its effects on joint health.

A systematic review by Liu et al. (2018) evaluating dietary supplements for osteoarthritis concluded that Boswellia extracts demonstrated clinically meaningful improvements in pain and physical function.

In a randomized, double-blind, placebo-controlled clinical trial, Majeed et al. (2019) evaluated a Boswellia extract in individuals with knee osteoarthritis. After 120 days of supplementation, participants experienced significant reductions in joint pain and improvements in physical function compared with the placebo group.

Boswellia contains several bioactive boswellic acids, with one of the most studied being 3-O-Acetyl-11-keto-β-boswellic acid (AKBA).

AKBA exhibits anti-inflammatory activity by inhibiting the enzyme 5-lipoxygenase (5-LOX), which plays a key role in the production of inflammatory leukotrienes.

Through this mechanism Boswellia extracts may help regulate inflammatory processes in the body.

Evidence from clinical studies suggests Boswellia serrata supplementation may help reduce joint discomfort associated with osteoarthritis.

Several studies reported reductions in pain comparable to some conventional anti-inflammatory medications while demonstrating favourable tolerability profiles.

Boswellia has been traditionally used in Ayurvedic medicine to support digestive health.

Clinical research investigating Boswellia gum resin in individuals with chronic inflammatory bowel conditions reported improvements in symptoms with minimal side effects, suggesting Boswellia may support inflammatory balance in the gastrointestinal tract.

A review investigating the effects of Boswellia species on metabolic syndrome found that Boswellia extracts may help improve insulin sensitivity and pancreatic beta-cell function.

These mechanisms may contribute to improved blood glucose regulation and metabolic balance.

Research suggests Boswellia may support liver health through antioxidant and anti-inflammatory mechanisms.

A clinical study found that supplementation with Boswellia serrata for six weeks reduced liver enzyme markers ALT and AST, suggesting a protective effect on liver tissue.

Boswellic acids influence immune system activity by modulating cytokine signalling pathways.

Research suggests boswellic acids inhibit NF-κB, reducing production of pro-inflammatory cytokines such as TNF-α.

Clinical research suggests Boswellia may support healthy lipid metabolism.

Supplementation with 300 mg Boswellia three times daily for six weeks increased HDL cholesterol and reduced LDL and total cholesterol.

A meta-analysis of randomized controlled trials published in 2024 found that Boswellia supplementation significantly improved pain, stiffness, and joint function in individuals with knee osteoarthritis compared with placebo.

Improvements were measured using validated clinical tools such as the WOMAC osteoarthritis index.

Boswellia serrata and curcumin influence different inflammatory pathways.

Curcumin regulates inflammatory signalling through the NF-κB pathway, while boswellic acids inhibit the 5-lipoxygenase enzyme responsible for producing inflammatory leukotrienes.

Because these compounds act on complementary pathways, combining Boswellia and Curcuma extracts may provide broader inflammatory support than either ingredient alone.

A double-blind, placebo-controlled clinical study by Andrade et al. (2000) investigated an ethanolic extract of ashwagandha in patients with anxiety disorders and concluded that ashwagandha demonstrated anxiolytic potential.

More recent clinical studies in healthy adults have continued to support these findings, reporting improvements in self-reported anxiety and stress-related outcomes.

A randomized, double-blind, placebo-controlled trial by Chandrasekhar et al. (2012) assessed ashwagandha’s effects in adults experiencing stress. Participants receiving 300 mg/day of a full-spectrum extract (standardized to withanolides) reported improvements in stress assessment outcomes, alongside a reduction in serum cortisol compared with placebo.

These findings support ashwagandha’s traditional use as an adaptogen (supporting the body’s ability to adapt to stress).

Clinical trials have reported that ashwagandha supplementation may improve stress-related outcomes such as perceived stress, fatigue, and overall wellbeing, which can contribute to improvements in daily functioning and quality of life.

VO₂max (maximal oxygen consumption) is a widely used indicator of aerobic capacity and endurance.

A systematic review and meta-analysis by Pérez-Gómez et al. (2020) found that ashwagandha supplementation was associated with a significant improvement in VO₂max in healthy adults and athletes, suggesting potential benefits for endurance and exercise capacity.

Ashwagandha may support energy and vitality through its role in stress adaptation and physical performance outcomes.

A randomized, double-blind, placebo-controlled crossover study by Lopresti et al. (2019) in aging, overweight males reported improvements in markers related to vitality, including fatigue, vigour, and aspects of psychological wellbeing.

A systematic review by Ng et al. (2019) evaluated clinical evidence for ashwagandha in cognitive dysfunction and reported potential benefits across cognitive domains relevant to age-related decline and neurocognitive conditions.

In addition to clinical findings in cognitive dysfunction, research suggests ashwagandha may support performance across cognitive tasks including attention, reaction time, and executive function.

A 2024 randomized controlled trial in healthy adults reported improvements across measures such as memory, attention, and vigilance following ashwagandha supplementation.

Ashwagandha has a long history of traditional use in Ayurveda for supporting rest and sleep. Modern trials have also investigated sleep quality outcomes, with some randomized placebo-controlled research reporting improvements in self-reported sleep quality in adults with sleep complaints.

Newer research continues to strengthen the evidence base for ashwagandha in stress, mood, sleep, and performance.

• A 2024 systematic review and meta-analysis reported that ashwagandha supplementation significantly reduced stress, anxiety, and cortisol compared with placebo across randomized controlled trials.
• A 2025 randomized, double-blind, placebo-controlled clinical study reported improvements in stress and anxiety symptoms, with additional positive effects reported for mood and sleep quality.
• A 2024 randomized controlled trial found that ashwagandha combined with resistance training supported improvements in muscle size, strength, and endurance outcomes compared with placebo.

Human research suggests resveratrol may support antioxidant status and oxidative balance. Espinoza et al. (2017) reported measurable effects after repeated administration, aligning with the broader evidence that polyphenols can influence oxidative stress pathways.

Early clinical evidence has suggested resveratrol may produce “calorie restriction-like” effects in humans, including changes in energy metabolism and metabolic markers in adults with obesity.

However, not all trials show benefit. Some longer or higher-dose studies in metabolic syndrome populations have reported no meaningful improvements (and in some cases unfavourable shifts in biomarkers), highlighting that results may depend on population, dose, and study duration.

In adults with type 2 diabetes, Brasnyó et al. (2011) reported improvements in insulin sensitivity markers and oxidative stress-related outcomes following resveratrol supplementation.

More recent evidence syntheses continue to explore resveratrol’s effects on inflammation and oxidative stress outcomes in type 2 diabetes, with conclusions generally supporting modest improvements, while still calling for larger, higher-quality trials.

Resveratrol has been studied for vascular and cardioprotective effects. In a clinical trial in patients with stable coronary artery disease, Magyar et al. (2012) reported improvements in measures including endothelial function and LDL cholesterol.

In addition, meta-analyses of randomized trials have found resveratrol supplementation can improve flow-mediated dilation (FMD), a widely used marker of endothelial function.

Resveratrol has been investigated for circulation and blood flow parameters, including cerebral blood flow. A randomized, placebo-controlled crossover study assessed resveratrol (alone or in combination with piperine) and reported changes in cerebral blood flow parameters.

More recently, resveratrol has continued to be studied in vascular-neuro contexts (including neurovascular coupling under sleep restriction), supporting ongoing interest in its vascular mechanisms.

A randomized, placebo-controlled trial in postmenopausal women found that regular resveratrol supplementation improved bone mineral density, particularly at clinically relevant skeletal sites.

That said, newer reviews/meta-analyses in postmenopausal populations have reported inconsistent results across outcomes (including bone-related outcomes), suggesting benefits may be context-dependent and influenced by dose, baseline status, and trial duration.

Recent research continues to investigate the biological mechanisms through which resveratrol may influence cellular health and metabolic pathways.

Experimental and clinical studies suggest resveratrol may interact with pathways associated with ageing and metabolic regulation, including:

• Activation of sirtuin pathways (SIRT1) — proteins involved in cellular stress resistance, DNA repair, and longevity-related processes.
• AMP-activated protein kinase (AMPK) signalling — a key metabolic regulator that influences energy balance, mitochondrial function, and glucose metabolism.
• Modulation of inflammatory pathways — including inhibition of NF-κB signalling, which regulates inflammatory cytokine production.
• Improved endothelial nitric oxide signalling — which may support vascular function and healthy blood flow.
• Antioxidant defence pathways — including upregulation of endogenous antioxidant enzymes such as superoxide dismutase (SOD), and activation of protective transcription factors such as Nrf2.

Because these pathways are associated with metabolic health, cardiovascular function, and cellular resilience, resveratrol continues to be widely studied as a compound of interest in longevity and preventative health research. However, researchers also note that human clinical outcomes vary depending on dosage, bioavailability, and study population, and further long-term trials are ongoing to clarify its role in health interventions.

Procyanidins are potent polyphenolic antioxidants. Research suggests grape seed extract may help regulate oxidative stress by modulating antioxidant enzyme activity and protecting cells from oxidative damage.

A systematic review and meta-analysis of controlled trials concluded that grape seed extract supplementation significantly improved markers of oxidative stress and inflammation in humans.

Procyanidins are known to interact with structural proteins such as collagen. Experimental and clinical research suggests these compounds may help stabilize collagen fibers and inhibit enzymes involved in collagen degradation.

This mechanism may contribute to improvements in skin elasticity and structural integrity, which are key components of skin ageing.

Emerging research has explored grape seed extract in relation to psychological wellbeing. A randomized, double-blind, placebo-controlled trial found that supplementation with grape seed extract was associated with improvements in perceived stress and mood in healthy adults.

Additional analyses from the same randomized clinical trial reported improvements in psychological measures including perceived stress and worry following grape seed extract supplementation.

These findings suggest grape seed extract may influence pathways involved in stress perception and psychological wellbeing, though further research is required to better understand the underlying mechanisms.

More recent research continues to investigate grape seed procyanidins for their potential role in vascular function and cardiometabolic health.

Meta-analyses of randomized clinical trials suggest grape seed extract supplementation may support:

• Endothelial function
• Blood pressure regulation
• Antioxidant defence systems

These effects are thought to be related to improved nitric oxide signalling, vascular elasticity, and reduction of oxidative stress.

Vascular ageing refers to the gradual decline in blood vessel elasticity and endothelial function that occurs with age. This process is associated with increased oxidative stress, inflammation, and reduced nitric oxide availability.

Procyanidins from grape seed extract have been studied for their ability to support vascular function by improving endothelial activity and promoting nitric oxide signalling. These mechanisms may help maintain healthy blood vessel flexibility and circulation.

Several clinical trials and meta-analyses have reported improvements in blood pressure, endothelial function, and markers of oxidative stress following grape seed extract supplementation. These findings suggest procyanidins may contribute to supporting cardiovascular health and healthy ageing.

Piperine has been widely studied for its ability to enhance the absorption of certain bioactive compounds. Research suggests piperine may influence enzymes involved in metabolism and increase intestinal absorption of specific nutrients and phytochemicals.

One of the most widely cited human studies demonstrated that combining piperine with curcumin significantly increased the bioavailability of curcumin compared with curcumin alone.