This post contains affiliate links, I may earn a small commission if you shop through my links, at no extra cost to you. I am not a medical professional. Always consult your GP or a qualified health practitioner before starting any new supplement.
The supplement industry is worth billions and it will tell you that you need all of it. You don’t. But there are a handful of things that the research genuinely supports — especially for women in their 40s. Here’s the honest version.
First, a word on supplements in general
I want to be upfront with you before we get into it: I am not a doctor, a nutritionist, or a registered dietitian. What I am is a woman in her 40s who has done a lot of reading, had a lot of conversations with health professionals, and spent more money than I care to admit testing things that didn’t do much.
The supplement industry is enormous, largely unregulated, and extremely good at marketing to women who are tired, hormonally shifting, and looking for solutions. Most of what’s on the shelves isn’t backed by solid evidence. Some of it is actively misleading. A few things, however, genuinely are.
What I’m sharing here is based on what the research actually supports, not what the packaging promises. I’ve focused specifically on women in their 40s because our needs change significantly from this decade onwards, and the generic “women’s multivitamin” rarely accounts for that.
Always, always check with your GP before starting anything new; especially if you’re on medication, as some supplements interact in ways that matter.
Supplement 1:
Vitamin D3 + K2
Strong evidence most women in the UK are deficient
If there’s one supplement that almost every woman in the UK should be taking, it’s vitamin D. We simply don’t get enough sun for our bodies to produce adequate levels and that’s before you factor in that our ability to synthesise vitamin D from sunlight decreases as we age.
Vitamin D is involved in bone density, immune function, mood regulation, and muscle strength. Deficiency is associated with fatigue, low mood, poor immune function, and increased risk of osteoporosis, all things we want to actively protect against in our 40s and beyond. The NHS recommends 10 micrograms (400 IU) daily, but many integrative health practitioners recommend higher doses, particularly through autumn and winter. A blood test through your GP will tell you exactly where you are.
The K2 pairing matters because vitamin D helps absorb calcium, and K2 helps direct that calcium into your bones rather than your arteries. They work best together.
Shop: Vitamin D3 + K2 — Holland & Barrett | My Vitamins-Vitamin D3 – LookFantastic
Supplement 02
Magnesium Glycinate
Strong evidence, especially for sleep, stress and muscle function
Magnesium is involved in over 300 enzymatic processes in the body. It supports sleep quality, nervous system regulation, muscle recovery, blood sugar balance, and hormone production. Most women don’t get enough through diet alone and stress, alcohol, and high caffeine intake all deplete magnesium further.
The form matters enormously here. Magnesium oxide (the most common and cheapest form) has poor absorption and is mostly useful as a laxative. Magnesium glycinate is the form with the best evidence for sleep and anxiety support, and it’s gentle on the stomach. Magnesium malate is better for energy and muscle recovery if that’s your priority.
I take magnesium glycinate about 30–45 minutes before bed and the difference in my sleep quality and how calm I feel going into the evening has been noticeable. This is one of the few supplements I genuinely wouldn’t be without.
Shop: Magnesium Glycinate – Boots | Magnesium Glycinate — Holland & Barrett
Supplement 03
Omega-3 (EPA + DHA)
Strong evidence across multiple areas
Omega-3 fatty acids specifically EPA and DHA from fish oil or algae are among the most researched supplements in existence. The evidence supports their role in cardiovascular health, brain function, inflammation reduction, joint support, and mood regulation.
For women in perimenopause and beyond, omega-3s have also shown promise in supporting mood stability and reducing the severity of hot flushes, though more research is ongoing. What is clear is that most of us don’t eat enough oily fish to meet optimal levels, and the cardiovascular and cognitive benefits are well enough established to make this a sensible daily addition.
Go for a high-quality fish oil with a combined EPA+DHA of at least 1000mg per day, or an algae-based omega-3 if you’re plant-based. Look for products that have been third-party tested for purity cheaper fish oils can contain mercury and oxidised fats, which aren’t doing you any favours.
Shop: Omega-3 Fish Oil — Holland & Barrett – Omega 3 Fish Oil- Boots
Supplement 04
Collagen Peptides
Good emerging evidence especially for skin, joints and hair
Collagen production begins declining in our mid-20s and accelerates significantly after menopause due to falling oestrogen levels. By our 40s, the effects are visible in skin texture and elasticity, in joint comfort, in hair quality.
The research on supplemental collagen has improved significantly in recent years. Hydrolysed collagen peptides, the form that’s been broken down for absorption have shown genuine results in studies looking at skin hydration and elasticity, joint pain reduction, and nail strength. The evidence isn’t quite as robust as for vitamin D or omega-3, but it’s compelling enough that I take it daily and have noticed a difference in my skin and nails over several months.
Look for a hydrolysed marine or bovine collagen powder with at least 10g of collagen peptides per serving. Pair it with vitamin C to support your body’s own collagen synthesis — the two work together.
Shop: Kiki Health Collagen Peptides — LookFantastic | Vital Proteins Collagen Peptides-Boots
Supplement 05
B12
Essential especially if you’re plant-based or have absorption issues
Vitamin B12 is essential for energy production, nerve function, red blood cell formation, and cognitive health. It’s found almost exclusively in animal products, which means anyone reducing or eliminating meat and dairy is at genuine risk of deficiency.
But here’s what’s less widely known: our ability to absorb B12 from food decreases with age, regardless of diet. By our 40s and 50s, lower stomach acid production means many women are absorbing less B12 even if they’re eating plenty of it. Symptoms of deficiency, fatigue, brain fog, low mood, tingling extremities are often mistaken for other things, including perimenopause.
A blood test will tell you where you stand. If you’re deficient, sublingual B12 (dissolved under the tongue) or a methylcobalamin spray offers better absorption than standard capsules.
Shop: Solgar Vitamin B12 1000µg – 100 Nuggets– Boots | Vit B Vitamin 12 – Holland & Barrett
Supplement 06
Iron
Only supplement if deficient but deficiency is very common in women
Iron deficiency is the most common nutritional deficiency worldwide, and women are disproportionately affected due to menstrual blood loss. Symptoms are easy to miss or attribute to other causes: persistent fatigue, brain fog, poor concentration, breathlessness, brittle nails, hair loss.
I want to be clear here: iron is one supplement you absolutely should not take without testing first. Too much iron is toxic, and supplementing when you don’t need it does more harm than good. But if a blood test reveals low ferritin (your iron stores), addressing it can be genuinely transformative. Energy levels, cognitive clarity, and hair growth can all improve significantly when iron is properly restored.
If you are supplementing iron, opt for a gentle form like iron bisglycinate rather than ferrous sulfate, which is harder on the digestive system. Take it with vitamin C to enhance absorption and away from tea, coffee and calcium.
Shop: Spatone Liquid Iron Sachets — Holland & Barrett | Floradix Iron + Herbs — Holland & Barrett
What I’d skip (despite the hype)
There are a few things I see constantly marketed to women in their 40s that I’d approach with much more scepticism:
Most proprietary “women’s health” blends the formulations are often underdosed across too many ingredients to make a meaningful difference in any of them. You’re paying a premium for the branding.
Most detox or “cleanse” supplements your liver and kidneys are your detox system and they work extraordinarily well. There is no credible evidence that any supplement meaningfully supports or accelerates this process beyond simply eating well, staying hydrated, and sleeping.
Before you spend a penny, get your bloods done
The single most useful thing you can do before buying a single supplement is to get a blood test. A full panel, including vitamin D, B12, ferritin, thyroid function, and a full blood count — will tell you exactly what you’re actually deficient in, so you’re not guessing.
Your GP can request this on the NHS, or you can use a private at-home blood testing service if you want more comprehensive results. Medichecks and Thriva both offer women’s health panels that cover the key markers and knowing your actual numbers is infinitely more useful than any recommendation I (or anyone else) can give you.
Supplement to your specific needs, not to a general list. Your body, your data.
Have you found a supplement that’s genuinely changed things for you? Drop it in the comments. I’m always curious what’s actually working for women at this stage. And if you’re unsure where to start, the honest answer is: get your bloods done first. Everything else follows from there.
*Always consult your GP or a qualified health professional before starting any new supplement, particularly if you are pregnant, breastfeeding, or taking medication.*
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