Reviewed by Steph BakerRegistered MSc NutritionistLast Updated: March 2026
✓Expert Reviewed
Bloating before your period. Skin that flares up at the worst possible time. Hot flushes that leave you reaching for a fan at your desk. For millions of women, these aren't just minor inconveniences. They're monthly disruptions that affect work, sleep, and quality of life.
Behind many of these issues is a shortage of gamma-linolenic acid (GLA), an omega-6 fatty acid your body struggles to produce efficiently on its own. As you age, your body becomes less efficient at converting the omega-6 fats in your diet into GLA. Stress, alcohol, and processed food accelerate this decline.
Evening primrose oil is one of the richest natural sources of GLA. Research suggests it may support hormonal comfort, skin hydration, and overall wellbeing during the menstrual cycle and menopause.
The problem? The quality of EPO supplements varies enormously. Extraction method, GLA concentration, and capsule type all determine whether you actually absorb what's on the label. We reviewed 20+ evening primrose oil supplements to find the 5 that deliver real GLA content, clean formulations, and genuine value.
Your Top Evening Primrose Oil Questions Answered
Who should take an evening primrose oil supplement?+
Evening primrose oil is most commonly taken by women experiencing PMS symptoms, menopause-related discomfort, or persistent skin dryness. Anyone whose diet is low in GLA, or whose body struggles to convert omega-6 into GLA efficiently, may also benefit. It is sometimes used alongside other supplements for general skin and hormonal wellbeing. If you are pregnant, breastfeeding, or taking prescription medication, consult your GP before starting EPO.
How much evening primrose oil should I take daily?+
Clinical studies typically use doses between 1,000mg and 3,000mg of EPO daily, depending on the intended use. The key figure to look for is GLA content per capsule, not just total oil weight. A good-quality 1,000mg capsule should deliver at least 80 to 90mg of GLA. For most people, one to two capsules daily with food is a practical starting point.
How long does evening primrose oil take to work?+
Skin improvements may appear within 4 to 6 weeks, while hormonal benefits typically take 2 to 3 full menstrual cycles to become noticeable. A study published in the International Journal of Dermatology reported measurable improvements in skin hydration after 12 weeks of supplementation.[5] GLA builds up gradually in cell membranes, so consistency matters more than dose size. Take it at the same time each day for best results.
Is evening primrose oil safe for long-term use?+
EPO has a well-established safety profile and has been used as a supplement for decades. Studies lasting 6 to 12 months have not reported significant adverse effects at standard doses.[6] However, EPO may interact with blood-thinning medications such as warfarin, and should be avoided by those taking epilepsy medication as it may lower the seizure threshold. If you take any prescription medication, speak to your GP before starting EPO supplementation.
Is evening primrose oil the same as starflower oil?+
No. Evening primrose oil (from Oenothera biennis) and starflower oil (from borage, Borago officinalis) are different plants that both contain GLA. Starflower oil typically has a higher GLA percentage per gram, but evening primrose oil has a longer history of clinical research and is generally considered gentler for long-term use. Some supplements blend the two oils together, which can make it harder to know exactly how much of each you are getting. If you specifically want evening primrose oil, check the label to confirm it is not a blend.
Why Take Evening Primrose Oil?
Hormonal balance and PMS support. GLA is a building block for anti-inflammatory prostaglandins, which play a central role in menstrual comfort. Women who experience bloating, mood changes, or breast tenderness in the days before their period may find that consistent EPO supplementation helps take the edge off. Research suggests GLA works best when taken daily throughout the cycle, not just during symptoms.
Skin hydration and barrier function. GLA supports the production of ceramides, the lipid molecules that hold your skin's moisture barrier together. When GLA levels are low, skin can become dry, flaky, or prone to irritation. Studies suggest that supplementing with evening primrose oil may improve skin hydration from the inside out, particularly for those with persistently dry or sensitive skin that topical moisturisers alone cannot resolve.
Menopause comfort. During perimenopause and menopause, fluctuating hormone levels can trigger hot flushes, disrupted sleep, and mood changes. Evening primrose oil is one of the most widely used natural supplements during this transition. While individual responses vary, many women report that regular EPO use helps smooth out some of the daily discomfort that accompanies hormonal shifts.
Inflammatory response support. Beyond hormonal health, GLA may help maintain a balanced inflammatory response throughout the body. This can be relevant for joint stiffness, general aches, and overall wellbeing. Because most Western diets are high in omega-6 but low in GLA specifically, supplementation offers a direct route to a nutrient your body struggles to produce efficiently on its own.
Research Suggests A Quality Evening Primrose Oil Supplement May:
✓Help support hormonal balance during the menstrual cycle
✓Help promote skin hydration and reduce dryness
✓Help ease menstrual discomfort and breast tenderness
✓May support comfort during the menopause transition
✓May help maintain a healthy inflammatory response
Choosing the Right Format For You
Even the best evening primrose oil can fail you if the format does not fit your routine. Each delivery method has trade-offs worth considering:
Softgel Capsules
Liquid Oil
Gummies
Ease of Use
Grab & go
Dropper & measure
Chew daily
Additives Risk
✓
✓
High
GLA Content Per Serving
★★★★★
★★★★
★★
Travel Friendly
✓
Fragile
✓
Best For
Daily use
Swallowing issues
Capsule-averse
Our recommendation: Softgel capsules offer the best balance of convenience, GLA potency, and clean formulation. Liquid oil suits those who cannot swallow capsules, while gummies sacrifice too much GLA content and add unnecessary sugars. If you follow a plant-based diet, check whether the capsule shell is vegan, as most EPO softgels use bovine or porcine gelatin. The best format is the one you will take consistently.
What To Look For In An Evening Primrose Oil Supplement
✓High GLA Content (80mg+ Per Capsule)
GLA is the active compound that makes evening primrose oil effective. Look for products that clearly state GLA content per capsule, not just total oil weight. A 1000mg capsule should deliver at least 80-90mg of GLA. Products that list only "1000mg evening primrose oil" without specifying GLA content may be using lower-quality oil.
✓Cold-Pressed Extraction
How the oil is extracted matters enormously. Cold-pressing uses mechanical pressure to squeeze oil from seeds without heat or chemical solvents. This preserves the delicate GLA and natural vitamin E content. Chemical extraction with hexane is cheaper but may degrade the very compounds you're paying for.
✓Added Vitamin E
Vitamin E acts as a natural antioxidant that protects the fragile omega-6 fatty acids in EPO from oxidation. Quality formulas include vitamin E to maintain freshness and potency throughout the product's shelf life. It also supports skin health in its own right, complementing GLA's benefits.
✓Vegan-Friendly Capsules
Most EPO supplements use bovine or porcine gelatin capsules, which limits their suitability for vegans and vegetarians. Plant-based capsule shells deliver the same oil without animal-derived ingredients. This is especially relevant given that EPO is a plant-based supplement to begin with.
✓GMP Manufacturing & Transparency
Quality supplements should be manufactured in GMP-certified facilities with full ingredient transparency. Look for brands that disclose their sourcing, extraction method, and exact GLA content per capsule rather than hiding behind vague labels.
✓Money-Back Guarantee
A money-back guarantee signals genuine confidence in the product. Since EPO takes several weeks of consistent use before benefits become noticeable, a 30 to 60 day return window gives you time to evaluate it properly. Brands that offer this are putting their reputation behind their formula.
What To Avoid In An Evening Primrose Oil Supplement
✗Signs of Rancid Oil
EPO is rich in delicate polyunsaturated fats that oxidise quickly when exposed to heat, light, or air. Always check the expiry date before purchasing. Once opened, capsules that smell sharp or fishy, or oil that has darkened in colour, may have gone rancid. Rancid oil delivers fewer active fatty acids and can cause stomach upset. Store your supplement in a cool, dark place and avoid products sold in clear packaging.
✗Misleading "Equivalent" Dosing Claims
Some brands advertise a large headline dose (e.g. "3000mg equivalent") that requires you to take three or more capsules per serving. The actual per-capsule dose may be far lower than it first appears. Always check the "per capsule" figures on the back label, not just the front-of-pack marketing claim. A genuine 1000mg capsule with stated GLA content is more transparent than an inflated equivalent figure.
✗No UK Address or Customer Service
Some EPO products sold in the UK are imported without a local distributor. If there is no UK address on the label and no accessible customer service team, returning a faulty product or raising a complaint becomes difficult. UK-based brands are also subject to UK food supplement regulations, which adds a layer of accountability that overseas-only sellers may not meet.
✗Blended or Diluted Oils
Some products blend evening primrose oil with other oils like starflower (borage) oil. While starflower oil also contains GLA, blending dilutes the pure EPO dose and makes it harder to know exactly how much of each oil you are getting. If you want EPO, choose a product that contains 100% evening primrose oil.
Top 5 Evening Primrose Oil Supplements Of 2026
After extensive testing and research, these are the products that made our list.
✓ 1000mg cold-pressed evening primrose oil per capsule
✓ 90mg GLA per capsule, one of the highest on the market
✓ Only vegan-friendly EPO capsule available in the UK
✓ Contains vitamin E (5.7mg, 47.5% NRV) for antioxidant protection
✓ Mechanically cold-pressed, no chemical solvents
✓ UK manufactured to GMP standards
✓ 60-day money-back guarantee
Cons
✗ Only available online
✗ No smaller trial pack available
The Bottom Line
What first caught our attention about Purolabs Evening Primrose Oil is something surprisingly rare in this category: it uses vegan-friendly capsule shells. Every other EPO product we reviewed relies on bovine or porcine gelatin, which feels like an odd choice for a plant-based oil. If you follow a vegetarian or vegan diet, this is currently the only UK option that does not compromise on the capsule itself.
Beyond the capsule, the formula holds up well. Each softgel delivers 1000mg of cold-pressed EPO with 90mg GLA, which sits at the top end of the market. Cold-pressing matters here because GLA is a fragile fatty acid. Heat and chemical solvents can degrade it before it reaches you. The added vitamin E (47.5% NRV) serves a practical purpose too, acting as an antioxidant that keeps the oil fresh throughout its shelf life.
It is manufactured in the UK to GMP standards. The 60-day money-back guarantee is genuinely useful for a supplement that takes several weeks of consistent use before you notice a difference.
Overall, Purolabs earns our top spot by combining high GLA content, clean extraction, and a vegan capsule shell that the rest of the market has not caught up with.
*Results and rankings are based on subjective opinion and do not necessarily reflect typical results from the use of these products. Please visit product website for more information.
✓ Highest GLA per capsule (115mg) of any product tested
✓ Uses New Zealand Rigel evening primrose oil
✓ Pharmacist-recommended brand
✓ Well-established reputation in the EPO category
Cons
✗ Only 30 capsules per box (1-month supply)
✗ Bovine gelatin capsules (not suitable for vegans)
✗ Doesn't confirm cold-pressed extraction
✗ 3-month cost (£31.32) reaches price parity with Purolabs
The Bottom Line
Efamol is arguably the most recognised name in evening primrose oil, and their High Strength formula backs that reputation with 115mg GLA per capsule, the highest of any product we tested.
The New Zealand-sourced Rigel EPO is a premium oil variety, and the brand carries strong pharmacist endorsement. For GLA potency alone, Efamol is hard to beat.
The main drawback is practical. Each box contains only 30 capsules, meaning you need to repurchase monthly. At approximately £10.44 per box, a 3-month supply costs £31.32, which is essentially the same as Purolabs' 45-day supply. The bovine gelatin capsules also rule it out for vegans, and the product does not explicitly confirm cold-pressed extraction.
An excellent choice for those prioritising maximum GLA content and brand heritage, provided you do not mind gelatin capsules and monthly reordering.
Best for: those who want maximum GLA potency from a pharmacist-recommended brand and are comfortable with gelatin capsules.
*Results and rankings are based on subjective opinion and do not necessarily reflect typical results from the use of these products. Please visit product website for more information.
Holland & Barrett is a name most UK shoppers know and trust, and this product takes an interesting approach by combining evening primrose oil with starflower (borage) oil in a single capsule. Both oils contain GLA, so the theory is sound.
The issue is transparency. Because the oil is blended, it is harder to know exactly how much EPO versus starflower oil you are getting in each capsule. If you specifically want pure evening primrose oil, this is not it.
At approximately £12.99 for 90 capsules, the per-capsule cost is competitive. However, there is limited real-world feedback on Amazon to draw from. The gelatin capsules rule out vegans, and the product does not disclose its manufacturing origin or extraction method.
A reasonable option for those who want a general GLA supplement from a familiar brand, but not ideal if you want pure, traceable EPO.
Best for: shoppers who want a convenient two-in-one GLA supplement from a familiar high-street brand.
*Results and rankings are based on subjective opinion and do not necessarily reflect typical results from the use of these products. Please visit product website for more information.
Efamol's liquid EPO offers the same premium New Zealand Rigel oil as their capsule version, delivering 904mg EPO and 103mg GLA per 1ml dropper serving. The generous 10mg vitamin E is a nice addition.
The challenge is entirely practical. Liquid oil format means measuring droppers, oily taste, and mandatory refrigeration after opening. At approximately £18.99 per bottle, the cost per serving is higher than capsule alternatives. Multiple Amazon reviewers mention the taste being difficult, especially for daily use over months.
The glass bottle also makes this a poor choice for travel or keeping in a handbag. It is essentially a stay-at-home supplement, which limits its usefulness for busy lifestyles.
A solid option for those who genuinely prefer liquids over capsules, or who have difficulty swallowing softgels. For everyone else, capsule formats are more practical.
Best for: those who prefer liquid supplements or have difficulty swallowing capsules.
*Results and rankings are based on subjective opinion and do not necessarily reflect typical results from the use of these products. Please visit product website for more information.
Horbaach's gummies will appeal to anyone who finds softgel capsules difficult to swallow. The mixed berry flavour makes daily supplementation genuinely enjoyable, and at 100 gummies per bottle, the supply lasts.
However, the trade-offs are significant. At 500mg EPO and just 42mg GLA per gummy, you are getting roughly half the dose of a standard 1000mg capsule. At approximately £10.99 for 100 gummies, the per-GLA cost is actually higher than capsule alternatives once you account for the lower dose.
The ingredient list includes glucose syrup, sugar, and artificial flavouring, which rather undermines the point of taking a health supplement. The product is also a US import with no indication of cold-pressed extraction.
Fine as an introductory EPO product for those who truly cannot take capsules. For serious hormonal or skin support, higher-dosed options deliver better results.
Best for: those who dislike capsules and want a pleasant-tasting introduction to EPO supplementation.
*Results and rankings are based on subjective opinion and do not necessarily reflect typical results from the use of these products. Please visit product website for more information.
This website is owned and operated by Purolabs Nutrition Ltd, which owns the product ranked number one on this page.
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