Common supplements people take for focus, energy and calm, graded by the strength of the human evidence. Not by how popular they are on social media.
Consistent results across many human trials and reviews.
Several decent human trials pointing the same way, with some caveats.
Some positive trials, but small, inconsistent or only in specific groups.
Mostly animal, lab or anecdotal evidence so far.
Alertness, attention, reaction time
The most reliable focus tool there is. Benefits appear at modest doses; more mostly adds side effects.
Avoiding dehydration-related fog
Losing about 2% of body weight in water measurably impairs attention. The cheapest fix on this list.
Calm focus; smoothing out caffeine
Modest on its own, but the caffeine pairing is one of the best-studied combinations in the field. Now available in pouch form.
Mental stamina, especially when sleep-deprived; memory in vegetarians
Best known for muscle, but brain benefits are real for some groups. Cheap, safe and extremely well studied.
Fixing deficiency (fatigue, low mood)
Not a focus booster if your levels are fine, but deficiency is common in the UK through winter, and fixing it matters.
Memory (with daily use)
One of the better-supported herbal nootropics for memory, but it does nothing acutely. Not a "take before work" supplement.
Long-term brain health; mood
Important for the brain structurally, but trials in healthy adults show little short-term effect on focus. Worth it if you never eat oily fish.
Sleep quality and muscle relaxation, if intake is low
Helpful mainly if your diet is low in it. The "magnesium fixes everything" trend runs well ahead of the evidence.
Falling asleep; next-day alertness
A few small trials show better subjective sleep quality and less next-day fatigue. Cheap and low-risk to try.
Fatigue under stress
Some trials show less mental fatigue in stressful periods; others show nothing. Quality varies wildly between products.
Stress and sleep
Trials on stress are promising, but many are small and industry-funded. Not a focus aid as such.
Attention
A handful of small trials in healthy adults show attention benefits. Interesting, but needs bigger studies.
Cognition (claimed)
Lots of hype, very little human data. Promising lab work hasn’t yet translated into convincing trials in healthy people.
Attention, reaction time
It genuinely sharpens attention short-term, but dependence is the price. If you don’t already use it, don’t start for focus.
Grades reflect evidence for the stated use in healthy adults, not safety, and can change as new research is published. Prescription-only drugs (such as modafinil, or melatonin in the UK) aren't covered. Always check with a pharmacist if you take medication.