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Last reviewed: 23 March 2026
I’ve spent over £800 on supplements this year. About half of them were completely pointless. Here’s what actually worked and what you should save your money on.
My Testing Approach
I didn’t just take these supplements for a week and call it a day. I committed to a minimum of three months per supplement — long enough to actually notice a difference. Where it made sense (Vitamin D, for example), I got blood tests done before and after to see whether the supplement was actually moving the needle, not just giving me expensive urine. I tracked energy, sleep quality, gym performance, and mood in a simple daily log. Nothing fancy — just honest notes. I also cross-referenced my experience against the published research on Examine.com and peer-reviewed studies on PubMed to make sure I wasn’t imagining results that weren’t there.
The Supplements That Actually Worked
1. Vitamin D3 + K2 — The One Everyone Should Take
I got a blood test in October last year and discovered I was deficient — my 25(OH)D level was sitting at 28 nmol/L, well below the optimal range of 75–125 nmol/L. Not a surprise given I live in the UK and spend most of my day at a desk. I started taking 4,000 IU of D3 paired with 100mcg of K2 (MK-7 form) daily. By February, my levels had climbed to 89 nmol/L. More importantly, the afternoon energy crashes I’d been writing off as just “winter” became noticeably less frequent. My mood improved too, though I appreciate that’s harder to quantify. If you’re based in the UK and not supplementing with D3 between October and March, you’re almost certainly deficient. This is the one supplement I’d recommend to literally everyone.
Verdict: 10/10
2. Magnesium Glycinate — Fixed My Sleep
I’d tried magnesium oxide before and it did nothing except upset my stomach. Magnesium glycinate is different. Within about two weeks of taking 400mg before bed, I was falling asleep faster and — more noticeably — waking up feeling actually rested rather than groggy. The research backs this up: magnesium plays a role in regulating the nervous system and GABA receptors, both of which are involved in sleep. The glycinate form is chelated to glycine, an amino acid that itself has calming properties and is better absorbed than oxide or citrate. I also noticed slightly less muscle soreness after heavy training sessions, which is a nice bonus. This one genuinely changed my sleep, and I’ve stayed on it ever since.
Verdict: 9/10
3. Creatine Monohydrate — Not Just for Bodybuilders
Everyone knows creatine helps with strength and muscle, but I was more interested in the cognitive research when I started taking it. There’s decent evidence that creatine supplementation improves short-term memory and processing speed, particularly in sleep-deprived people or vegetarians (who tend to have lower baseline creatine stores). I took 5g per day — no loading phase, no fancy forms, just bog-standard creatine monohydrate from a reputable brand. My one-rep max on the bench went up by about 7.5kg over three months, which isn’t nothing. And on days when I was running on six hours’ sleep, I did feel sharper than I’d expect. Creatine is one of the most researched supplements in existence. It works, it’s safe long-term, and it’s cheap. No reason not to take it.
Verdict: 9/10
The Ones That Were Basically Useless
4. Collagen Peptides — Sorry, but No
I really wanted this one to work. I was spending £35 a month on a premium collagen powder, stirring it into my morning coffee, convinced it was helping my joints and skin. After three months, I honestly couldn’t tell the difference. The problem isn’t just my experience — it’s the science. When you consume collagen, your digestive system breaks it down into amino acids, which are then used wherever your body decides to direct them. The idea that consuming collagen directly translates to more collagen in your skin or joints is a simplification that the evidence doesn’t fully support. If joint health is your goal, you’d be better off with Vitamin C (which supports collagen synthesis) and glucosamine. If skin health is the goal, look at your overall diet and hydration first. Expensive and largely unproven.
Verdict: 4/10
5. Ashwagandha — Overhyped
Ashwagandha is everywhere right now, and the research isn’t terrible — there are some decent RCTs showing reductions in cortisol and improvements in stress markers. But personally? I felt nothing. I tried two different brands (KSM-66 extract, which is the most studied form) at the recommended dose of 600mg per day for four months. My sleep was already improved from the magnesium, my stress levels didn’t noticeably shift, and I had no measurable change in my gym performance. It’s possible ashwagandha works better for people with clinically elevated cortisol, or those under more significant chronic stress than I was experiencing at the time. For me, it was £25 a month I didn’t need to spend. Your experience might differ.
Verdict: 5/10
Where I Buy My Supplements
For most of my supplements, I use Bulk and MyProtein for basics like creatine and magnesium. For more specialised supplements like Vitamin D3/K2, I’ve had good experiences with Thorne and Nutri Advanced — both of which are third-party tested and used by healthcare professionals. Avoid anything with a “proprietary blend” that hides dosages, and always check for third-party certifications like Informed Sport or NSF if you’re an athlete subject to drug testing. You can also find well-reviewed options on sites like our supplements page where we break down the best options by category.
FAQ
What supplements are actually worth taking?
Based on evidence and personal experience, the core stack most UK adults would benefit from is: Vitamin D3 + K2 (especially October to March), magnesium glycinate (if your sleep or stress levels aren’t great), and creatine monohydrate (if you exercise or want cognitive support). Beyond that, it depends on your individual blood work and goals.
Should I take a multivitamin?
It depends. A decent multivitamin can act as nutritional insurance, but many are poorly dosed or use inferior forms of vitamins and minerals. If your diet is varied and you’re not deficient in anything specific, a multivitamin may not add much. If you eat a restricted diet or have confirmed deficiencies, a targeted supplement protocol (rather than a multi) will usually serve you better.
How long should I try a supplement before judging it?
At least 8–12 weeks for most supplements. Many people give up after two weeks when they don’t feel anything dramatic, but most evidence-backed supplements work subtly over time — especially things like magnesium and Vitamin D. Get baseline blood work if possible, and track your results systematically rather than relying purely on how you feel day to day.
The Bottom Line
The UK supplement market is flooded with overpriced, underdosed, and overmarketed products. Most of what’s sold in high street health shops isn’t worth the money. But there are a handful of supplements with solid evidence behind them that can genuinely make a difference to your health, energy, and performance. Stick to those, buy from reputable brands, and don’t let clever marketing convince you that a new superfood blend is going to change your life. It won’t. Vitamin D, magnesium, and creatine? Those just might.
