Supplements: Which Ones Actually Work — And Which Ones Are Probably Just Expensive Urine?

The supplement industry is enormous. We are constantly told we need powders, pills and capsules for energy, hormones, fat loss, gut health, sleep, immunity, anti-ageing and performance. And yet many people spend hundreds of pounds each month on supplements they don’t really need — often without knowing:

what they’re supposed to do,
whether there’s actual science behind them,
or whether they’re even appropriate for them in the first place.

The truth is some supplements can be genuinely helpful. But they tend to work best when they:

correct a deficiency,
support a real physiological need,
or complement a solid lifestyle.

Supplements are not magic! They supplement your lifestyle — they do not replace it.

Here we discuss:

Considerations before purchasing
A reference guide for the most common supplements
What is the recommended dose?
The best supplements for menopause and beyond
Which supplements should men be taking?

Before You Buy Anything: Read This First

1. Try One New Supplement at a Time

If you start five supplements together and suddenly feel better (or worse), you have no idea which one caused the change.

Introduce one at a time and monitor: energy, sleep, digestion, recovery, mood, training performance, symptoms, and ideally blood markers where appropriate.

2. If You're Taking Loads of Supplements… Start Again

Many people end up with cupboards full of supplements and no clue what is actually helping. If that's you: stop, simplify, focus on fundamentals, then reintroduce things deliberately and slowly and monitor your changes.

3. Food, Sleep & Training Still Matter More

The best-supported "supplements" for long-term health are still: resistance training, cardiovascular fitness, sleep, protein intake, stress management, and a nutrient-dense diet. Those things outperform most supplement stacks.

4. Red Flags in the Supplement Industry

Be cautious if products promise: detoxification, hormone balancing, rapid fat loss, metabolism boosting, anti-ageing miracles, or "scientifically proven" benefits without actual human trials.

Remember: testimonials are not evidence, animal studies are not human RCTs, and expensive does not automatically mean effective.

The Evidence-Based Supplement Reference Guide

Supplement	What People Hope It Will Do	Most At-Risk Groups	Plausible Biological Mechanism?	What Human RCTs Actually Suggest	Risks If Unnecessary
Vitamin D	Immunity, mood, energy, bone health	UK population, low sun exposure, darker skin, older adults	Yes — involved in calcium regulation, immune signalling and muscle function	Strong evidence for correcting deficiency and improving bone health; mixed evidence for mood/immunity unless deficient	Toxicity possible above 100mcg (4,000 IU)/day
Creatine Monohydrate	Strength, muscle, recovery, cognition	Vegetarians/ vegans may have lower stores	Yes — improves rapid ATP energy availability	Very strong evidence for improved strength, lean mass and high-intensity performance. Recent (2024) meta-analyses also show modest cognitive benefits, particularly under sleep deprivation or in older adults	Water retention, mild GI upset
Protein Powder	Muscle gain, recovery, appetite control	Older adults, vegans, low protein intake	Yes — provides amino acids needed for muscle protein synthesis	Effective when overall protein intake is inadequate	Usually unnecessary if protein intake already sufficient for level of activity
Omega-3 (EPA/DHA)	Heart health, brain function, inflammation	Low oily fish intake	Yes — incorporated into cell membranes and inflammatory pathways	Moderate evidence for triglyceride reduction and cardiovascular benefit	High doses may affect bleeding risk, especially alongside blood-thinning medication
Magnesium	Sleep, stress, relaxation, muscle function	Poor diet, GI disorders, older adults	Yes — involved in hundreds of enzymatic reactions	Some evidence for sleep quality and migraine reduction in deficient people	Diarrhoea/GI upset
Vitamin B12	Energy, cognition, nerve function	Vegans, vegetarians, older adults	Yes — essential for red blood cells and nervous system	Strong evidence for correcting deficiency symptoms	Usually low risk
Iron	Energy, reduced fatigue, endurance	Menstruating women, heavy periods, pregnancy	Yes — essential for oxygen transport	Strong evidence if deficient; little benefit if levels normal	Iron overload can be harmful - fatigue, weakness, joint pain, brain fog, mood changes, low libido
Calcium	Bone health	Older adults, low dairy intake, post-menopausal women	Yes — essential for bone mineralisation	Helpful when dietary intake is low	Kidney stone risk in excess
Collagen (Hydrolysed)	Skin elasticity/ hydration, "anti-ageing," hair, nails, general joint support	Ageing adults	Yes, in theory — provides amino acid building blocks (mostly Type I/III), though supplying the raw material doesn't guarantee the body uses it to make new skin collagen	Weak/unclear once you control for funding: a 2025 meta-analysis of 23 RCTs (1,474 people) found industry-funded trials showed a skin benefit, but independently-funded, higher-quality trials showed none — current conclusion is no reliable evidence for skin ageing	Usually low risk, just likely a waste of money for skin claims specifically
Collagen (Undenatured Type II / UC-II)	Joint pain and stiffness, specifically in osteoarthritis	Ageing adults with joint pain, athletes	Yes, but via a different route entirely — thought to work through gut immune tissue ("oral tolerance"), calming joint inflammation, not by supplying building blocks	Reasonably solid: multiple RCTs (incl. a 180-day double-blind trial) show reduced knee osteoarthritis pain/stiffness and improved function vs. placebo	Usually low risk
Probiotics	Gut health, bloating, immunity	After antibiotics, IBS sufferers	Plausible but highly strain-specific	Some strains help IBS and antibiotic-associated diarrhoea	Often expensive with unclear exact benefit
Ashwagandha	Stress reduction, sleep	Not deficiency-related	May affect cortisol/stress pathways	Some small RCTs show reduced stress and improved sleep	Medication/thyroid interactions
Turmeric/ Curcumin	Reduce inflammation and pain	Not deficiency-related	Anti-inflammatory properties	Some evidence for osteoarthritis symptom relief	GI upset possible; may interact with blood-thinning medication
Electrolytes	Hydration and performance	Heavy sweaters, endurance athletes	Yes — fluid and nerve regulation	Useful during prolonged sweating/exercise	Excess sodium unnecessary for sedentary people
Melatonin	Sleep support	Older adults may produce less naturally	Regulates circadian rhythm	Good evidence for jet lag and certain diagnosed sleep disorders — but see important note below	Daytime drowsiness; in the UK, only available on prescription — see below
Multivitamins	“General health insurance”	Restrictive diets, frailty	Theoretical broad support	Usually little measurable benefit in healthy adults, though a couple of large recent trials have suggested a modest cognitive benefit in older adults — evidence is still mixed, not a reason to take one "just in case"	Expensive and often unnecessary
Greens Powders	“Fill nutritional gaps”	Often marketed generally	Mostly theoretical	Limited high-quality evidence	Expensive
Soy Isoflavones	Reduce hot flushes, night sweats and other menopausal symptoms	Peri- and post-menopausal women, particularly those not using HRT	Yes — soy isoflavones are phytoestrogens that can weakly bind to oestrogen receptors	Moderate evidence for modest reduction in hot flush frequency/severity in some women, though response varies considerably between individuals	Usually low risk for most people; may cause digestive upset in some individuals. People with hormone-sensitive medical conditions (including a history of oestrogen-receptor-positive breast cancer) should seek medical advice first

A note on collagen specifically: I've split "collagen" into two separate lines above because they're genuinely different products, not two doses of the same thing:

Undenatured Type II collagen (UC-II) — typically from chicken sternum cartilage, kept unheated rather than broken down — is the one with solid joint-pain evidence, at a tiny 40mg/day.

Standard hydrolysed collagen — broken into peptides, several grams a day, what's actually in most tubs and drinks on the market — is the one people buy for skin, and that's the claim with weak evidence once independent trials are separated from industry-funded ones.

Worth knowing too: eating more chicken doesn't substitute for UC-II. Regular chicken meat has very little collagen to begin with (it's concentrated in cartilage most people don't eat), and cooking denatures collagen — which is the opposite of the unheated state the UC-II mechanism depends on.

And the same logic applies to "just eat more beef/fish instead of buying hydrolysed collagen": beef and fish do contain the same collagen (mostly Type I), but again it's mainly in the skin, tendons and bones, not the muscle meat most people eat — you'd need bone broth, oxtail, brisket or fish skin to get any meaningful amount, and even those are unreliable: one study found commercial bone broths ranged from under 1g to over 6g of protein per 250ml serving, without even knowing how much of that was collagen. A standard hydrolyzed collagen supplement delivers a known, consistent amount every time (roughly 3.3g glycine, 1.1g proline and 1g hydroxyproline per 10g dose) — food doesn't. That said, glycine and proline aren't essential amino acids (the body makes its own), so given the weak evidence for hydrolyzed collagen's skin benefits above, neither the supplement nor deliberately eating more collagen-rich food is something we'd currently say is worth chasing for skin — a varied protein intake already covers it.

A note on melatonin specifically: unlike in the US, where melatonin is sold as an everyday over-the-counter supplement, in the UK melatonin is a prescription-only medicine (POM). You can't legally buy it in a pharmacy or shop here, and buying it online from an unlicensed seller isn't just inadvisable — it's illegal. GPs can prescribe it for short-term use, most commonly to adults 55+ with insomnia. If sleep is the goal, it's worth talking to your GP rather than sourcing it yourself — and in the meantime, sleep hygiene, magnesium, and reducing evening light exposure are the accessible, low-risk starting points from the list above.

Commonly Used Evidence-Based Doses

These are general adult dosing ranges used in research and clinical practice — not personal medical advice. More is not always better, and some supplements are best guided by symptoms or blood tests.

Supplement	Common Evidence-Based Dose	Notes
Vitamin D	1,000–2,000 IU (25–50 mcg) daily	The NHS baseline recommendation is 10mcg (400 IU) daily for everyone in autumn/winter, and year-round for those at higher risk (darker skin, low sun exposure). Higher doses (as shown) are commonly used clinically to correct a diagnosed deficiency — blood testing can help guide need. Safe upper limit: 100mcg (4,000 IU)/day During & Post Menopause: Often 1,000–2,000 IU/day in the UK
Creatine Monohydrate	3–5 g daily (or ~0.1 g/kg bodyweight/day)	No loading phase necessary — a "loading phase" (20–25 g/day, split into several doses, for 5–7 days) just saturates your muscles with creatine faster. Skip it and take 3–5 g/day from day one and you reach the same fully-saturated level, it just takes 3–4 weeks instead of about a week. Consistency matters more than timing. Some evidence supports going higher than 5g: larger/more muscular people may need proportionally more to fully saturate (hence the bodyweight-based dose), and brain/cognitive benefits specifically appear to need higher intakes (studies showing cognitive effects have used ~8g/day or more) since creatine crosses into the brain less easily than into muscle. For general strength and muscle goals, though, more than 5g/day hasn't been shown to add extra benefit once stores are saturated — the rest is just excreted
Protein Powder	Enough to help total protein intake reach ~1.2–2.0 g/kg/day protein overall	Midlife adults doing resistance training often benefit from aiming toward the higher end. During & Post Menopause: ~25–40 g protein per meal
Omega-3 (EPA/DHA)	~1–2 g combined EPA/DHA daily	Check actual EPA/DHA content — fish oil capsule amounts can be misleading.
Magnesium	200–400 mg elemental magnesium daily	Glycinate often better tolerated for sleep/stress; citrate may loosen stools.
Vitamin B12	250–1,000 mcg daily (oral)	Vegans often need regular supplementation long-term.
Iron	Usually 14–65 mg elemental iron daily depending on deficiency severity	Ideally guided by blood tests. Higher doses often worsen constipation/nausea.
Calcium	Aim for ~700–1,200 mg/day total intake from food + supplements combined	Food first preferable where possible. During & Post Menopause: Ensure total calcium intake reaches ~1,000–1,200 mg/day
Collagen (Hydrolysed)	2.5–15 g daily (most studies use the lower half)	Often combined with vitamin C. Worth knowing the current evidence for skin/anti-ageing claims specifically is weak — see the note below the reference guide table
Collagen (UC-II)	~40 mg daily	A completely different dose and product to hydrolysed collagen above — check the label specifically says "undenatured Type II" or "UC-II," not just "collagen"
Probiotics	Strain dependent	There is no universal “best dose.” Effects are highly strain-specific. I think something like a kefir with lots of strains (15 -30) is your best bet for overall health.
Ashwagandha	300–600 mg/day standardized extract	Usually divided once or twice daily.
Turmeric/ Curcumin	500–1,500 mg/day curcuminoids	Often paired with black pepper extract (piperine) for more absorption.
Electrolytes	Depends heavily on sweat losses/activity	Endurance athletes may require significantly more sodium than sedentary individuals.
Melatonin	0.3–3 mg 30–60 mins before bed (Please note that tablets from America are often 5mg which is way higher than the recommended dose.	In the UK this is prescription-only — dose and suitability should be set by a GP, not self-selected. (For reference, US over-the-counter tablets are often 5mg — considerably higher than doses typically used in UK clinical practice.)
Multivitamins	As per product	Avoid mega-dose formulations unless medically indicated.
Greens Powders	Product dependent	Evidence varies massively between brands.
Soy Isoflavones	~40–80 mg/day	Most commonly studied range for menopausal symptoms.

More Is Not Better

Many people assume: "If a little helps, more must help more." That is often untrue with supplements. Some nutrients become harmful in excess, particularly: iron, vitamin A, vitamin D, selenium, and calcium.

Check the Actual Ingredient Amounts

Many products are under-dosed or use "proprietary blends" where you can't even see meaningful ingredient quantities.

Quality Matters

Supplements are not regulated as tightly as medications. Look for: third-party testing, transparent ingredient lists, and evidence-based dosing rather than marketing claims.

Food First Still Wins

Supplements can help fill gaps, but they cannot compensate for: chronic sleep deprivation, inactivity, high stress, low protein intake, or a poor overall diet.

Supplements For Menopause: What Actually Matters?

This is where supplements can sometimes become more relevant — but not always for the reasons social media suggests.

Many peri- and post-menopausal women are marketed supplements claiming to "balance hormones," "fix menopause naturally," "boost metabolism," or "melt belly fat." The evidence for many of these products is weak.

What is strongly supported by science is focusing on: preserving muscle, supporting bone density, maintaining metabolic health, improving recovery, and supporting sleep and cardiovascular health.

Why Nutritional Needs Can Change During Menopause

As oestrogen declines, women become more vulnerable to: muscle loss, reduced bone density, increased visceral fat storage, poorer recovery, insulin resistance, sleep disruption, and changes in connective tissue quality.

That's why supplements that support strength training, adequate protein intake, bone health, and recovery often make far more sense than expensive "hormone balancing" blends.

The Most Evidence-Based Supplements for Peri & Post-Menopausal Women

Supplement	Why It May Help
Protein	Helps preserve muscle mass, strength, recovery and metabolic health
Creatine Monohydrate	Strong evidence for preserving strength, muscle mass and training performance during ageing. Emerging evidence (2024 meta-analyses) suggests possible benefits for brain energy, fatigue and cognition, though this research is still developing.
Vitamin D	Important for bone and muscle health, especially in the UK
Calcium	Helpful if dietary intake is low
Omega-3	May support cardiovascular and inflammatory health
Magnesium	May support sleep and relaxation in some individuals
Collagen (UC-II)	Best-evidenced option here — helps with joint pain/stiffness specifically
Soy Isoflavones	May modestly reduce hot flushes in some women
Melatonin	Can help some women struggling with sleep disruption — but requires a GP prescription in the UK, so this starts with a conversation with your doctor, not a purchase

Which supplements are better for men?

Men can absolutely benefit from some supplements too — particularly as they age. Ageing men may also experience: gradual muscle loss, reduced recovery, lower activity levels, poorer sleep, and declining protein intake.

Interestingly, many of the most useful supplements are actually very similar to those for women: protein, creatine, vitamin D, omega-3, and occasionally magnesium.

The big difference is that men are less likely to need: iron supplementation, calcium support, or menopause-specific symptom management.

References

Vitamin D

NHS — Vitamin D

Creatine

Melatonin

Multivitamins

Turmeric/Curcumin

Turmeric: potential interactions — Welsh Medicines Information Centre (NHS Wales)

Collagen (Hydrolyzed vs. UC-II)

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