We’ve tested hundreds of supplements and reviewed thousands of studies. This is our definitive guide to what actually works — and what’s a waste of your money.
Last Updated: 21 March 2026
How We Test Supplements
Our methodology: 3-month testing periods, blood marker tracking, peer-reviewed evidence assessment, third-party testing verification.
Read our full editorial policy
Essential Supplements (Almost Everyone Should Consider)
Vitamin D3 + K2
Vitamin D3 and K2 work synergistically to support bone health, immune function, and cardiovascular health. Most people in the UK are deficient in vitamin D, especially during winter months.
Read our Vitamin D3 and K2 guide
Magnesium
Magnesium is involved in over 300 enzymatic reactions in the body. It supports muscle function, sleep quality, and cognitive performance.
Read our Magnesium supplement guide
Omega-3 Fatty Acids
Omega-3 fatty acids (EPA and DHA) support heart health, brain function, and reduce inflammation. Quality and purity of the source matter enormously.
Read our Omega-3 Fish Oil guide
Performance Supplements
Creatine Monohydrate
Creatine monohydrate is one of the most researched supplements in existence. It consistently improves strength, power output, and muscle mass when combined with resistance training.
Read our Creatine Monohydrate guide
Pre-Workout Formulas
Pre-workout supplements can enhance energy, focus, and performance. However, ingredient quality and transparency vary enormously between brands.
Protein Powders
Protein supplementation supports muscle repair and growth. Whey, casein, and plant-based proteins all have their place depending on your goals and dietary preferences.
Read our Nootropics and Performance guide
Cognitive Enhancement (Nootropics)
Lion’s Mane Mushroom
Lion’s Mane contains compounds called hericenones and erinacines that may stimulate nerve growth factor (NGF) production, supporting brain health and cognitive function.
Bacopa Monnieri
Bacopa is an Ayurvedic herb with strong evidence for improving memory formation, information processing, and reducing anxiety.
L-Theanine + Caffeine
The combination of L-Theanine and caffeine is one of the most reliable cognitive stacks. L-Theanine smooths out the stimulant effects of caffeine while amplifying focus.
Read our full Nootropics guide
Weight Management Supplements
Glucomannan
Glucomannan is a water-soluble dietary fibre that expands in the stomach, promoting feelings of fullness and supporting weight management when combined with a calorie-controlled diet.
Green Tea Extract
Green tea extract contains EGCG and caffeine, which may modestly increase metabolic rate and fat oxidation. Effects are real but modest.
CLA
Conjugated Linoleic Acid (CLA) has mixed evidence for weight management. Some studies show modest reductions in body fat, but results are not consistent.
Read our Weight Loss Supplements guide
Longevity and Anti-Ageing
NAD+ / NMN
NAD+ precursors like NMN and NR are being studied for their potential to slow cellular ageing and support mitochondrial function. Early research is promising.
Resveratrol
Resveratrol, found in red grapes and berries, activates sirtuins — proteins associated with longevity. Bioavailability is a key challenge with resveratrol supplements.
CoQ10
Coenzyme Q10 is critical for mitochondrial energy production and acts as a powerful antioxidant. Levels naturally decline with age.
Read our Longevity Supplements guide
Joint Health and Recovery
Collagen
Collagen peptides support joint cartilage, skin elasticity, and connective tissue repair. Type II collagen specifically targets joint health.
Read our Collagen Supplements guide
Glucosamine
Glucosamine is a naturally occurring compound that supports cartilage structure. Most effective for those with existing joint discomfort.
Omega-3
Omega-3 fatty acids reduce inflammatory markers and support joint lubrication. Regular supplementation can reduce exercise-induced joint soreness.
Supplements to Avoid
Not all supplements are worth your money. Products with weak evidence, misleading marketing, or safety concerns to be wary of include:
- Detox supplements — Your liver and kidneys already do this job. There is no credible evidence that any supplement “detoxes” your body.
- Proprietary blends — Products that hide individual ingredient doses behind “proprietary blend” labels cannot be properly evaluated for efficacy or safety.
- Fat burners with stimulant stacks — Many contain unregulated stimulants at doses that carry cardiovascular risk.
- Colloidal silver — No proven health benefit and can cause permanent skin discolouration (argyria).
See our full review: UK’s Top-Selling Supplements — Most Are a Waste of Money
FAQ
How do I know if a supplement is high quality?
Look for products that have been independently tested by third parties such as Informed Sport, NSF, or USP. These certifications verify that what’s on the label is in the product, and that it’s free from banned substances and contaminants.
What’s the right dose for most supplements?
Dosing varies by supplement and individual. We recommend starting at the lower end of evidence-based dosing ranges and adjusting based on response. Always consult a healthcare professional if you have a medical condition or take prescription medications.
Which supplement brands can I trust?
Brands with strong reputations for transparency include those that publish full ingredient lists with exact doses, use third-party testing, and don’t make exaggerated health claims. We review specific brands throughout this site.
Can I take multiple supplements together?
Many supplements can be safely combined. However, some interactions exist — for example, high-dose zinc can interfere with copper absorption, and blood-thinning supplements should not be combined without medical supervision. Always research combinations before stacking.
Start Your Research
Use this guide as your starting point. Each section links to detailed, evidence-based reviews where we go deeper on dosing, brands, and the science. Our goal is to help you spend smarter and supplement with confidence.
Read about our testing methodology | Weight management | Nootropics | Longevity