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News, research and guides
348 articles from our editorial and science team.
GuidesBenzoyl Peroxide Plus Clindamycin vs Azelaic Acid — What a Head-to-Head Trial Shows in Acne Vulgaris
Acne vulgaris is one of the most common skin conditions, and pharmacy shelves offer several proven topical treatments competing for attention. Azelaic acid is often marketed as a gentler, "natural" alternative, while benzoyl peroxide combined with clindamycin is positioned as a proven, stronger classic. One of the few direct head-to-head trials, published in the Journal of the European Academy of Dermatology and Venereology, pitted both regimens against each other in more than 200 patients with mild-to-moderate acne — and the result is not as clear-cut as the "gentler option" marketing narrative would suggest.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesVitamin D and Psoriasis — Does Oral Supplementation Ease Symptoms?
Topical creams and ointments containing vitamin D analogues have long been standard, prescription treatment for psoriasis — that much is well established in dermatology. Far less clear is whether ordinary oral vitamin D supplementation — the same kind many people take in autumn and winter for immunity — has any effect on the course of the disease. A 2021 systematic review and meta-analysis of randomized trials tried to answer that question, and the result is more ambiguous than it might seem at first glance.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesProbiotics and Eczema in Children — Do They Prevent Atopic Dermatitis?
Atopic dermatitis (AD, eczema) is one of the most common chronic skin diseases in infants and young children. For years, researchers have studied whether giving probiotics during pregnancy and early infancy can reduce the risk of it occurring in children at elevated risk. A large meta-analysis of 37 randomized trials involving more than 6,000 children shows a moderate but statistically significant protective effect — provided the probiotic reaches the child within the right, early time window. This is prevention in at-risk children, however, not treatment of already existing eczema — and that distinction is crucial.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesIvermectin for Rosacea — How Does It Compare to Azelaic Acid?
Rosacea is a completely different disease from common acne, despite the confusingly similar name — and it needs different treatment. Ivermectin 1% cream is one of the newer treatment options, tested in two 40-week extension trials against azelaic acid 15%. We explain exactly what these trials showed, what they didn't show, and why this is primarily long-term safety data rather than a classic head-to-head efficacy contest.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesZinc and Tinnitus — What Does the Cochrane Review Show?
Tinnitus can be exceptionally distressing, and treatment options remain limited — no wonder people affected by it look for solutions among supplements, including zinc. Cochrane, one of the most rigorous evidence-evaluating institutions in medicine, analyzed the available clinical trials on the topic. The result is an instructive lesson in the difference between a promising biological hypothesis and what well-designed studies in humans actually confirm.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesVitamin D and Asthma Exacerbations in Children — What Does the Meta-Analysis Show?
Asthma is the most common chronic childhood disease, and its exacerbations often lead to emergency room visits and hospitalizations. A 2024 meta-analysis of ten randomized trials examined whether vitamin D supplementation in children with asthma actually reduces the number of such exacerbations — and found a statistically significant, though moderate, effect. This is not, however, a reason to treat vitamin D as a substitute for asthma control medications, nor an argument for supplementing a child on your own without the treating doctor's knowledge.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesPulmonary Rehabilitation and COPD — What Does the Cochrane Review Show?
Chronic obstructive pulmonary disease (COPD) traps patients in a vicious cycle: breathlessness on exertion discourages movement, avoiding movement deepens deconditioning, and deconditioning worsens breathlessness at ever-lower levels of effort. Pulmonary rehabilitation — a structured exercise program combined with education, not just "breathing exercises" — is one of the few interventions that genuinely breaks this mechanism. The largest Cochrane review on the topic covered 65 randomized trials and nearly 3,800 participants — we look at exactly what it found.
MNMichał Nowak11 min
August 27, 2026
GuidesRiboflavin (Vitamin B2) and Migraine — What Does the Meta-Analysis Show?
Magnesium isn't the only supplement with meaningful scientific backing for migraine prevention. Riboflavin, vitamin B2, works through a completely different mechanism — not neurotransmission and vascular tone, but supporting the energy metabolism of nerve cells. A 2022 meta-analysis of nine studies and 673 participants shows that supplementing 400 mg of riboflavin daily for three months significantly reduced the number of migraine days, attack duration, frequency, and pain intensity. In this article we examine exactly what these results mean, how strong the evidence is, and why riboflavin is a separate, complementary option to magnesium rather than a substitute for it.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesThe Ketogenic Diet and Drug-Resistant Epilepsy in Children — What Did the First Randomized Trial Show?
Before the ketogenic diet became a popular weight-loss approach, for nearly a hundred years it was — and still is — a serious, medically supervised therapy used in children with drug-resistant epilepsy, meaning epilepsy that can't be controlled despite correctly chosen antiepileptic drugs. In 2008, the first randomized controlled trial was published testing this intervention in a scientifically rigorous way — and it confirmed what neurologists had observed clinically for decades. This is an entirely different context than today's popular use of the keto diet for weight loss, which is easy to forget when seeing the same words applied to both.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesExercise and Parkinson's Disease — What Does the Meta-Analysis Show?
Parkinson's disease is a progressive neurodegenerative condition that cannot be reversed or "cured" by exercise alone. Yet a meta-analysis of 18 randomized trials with 901 patients shows that regular aerobic physical activity, carried out alongside pharmacological treatment, is associated with a moderate, statistically significant improvement in motor function. We explain exactly what was measured, how large this effect is, and why exercise remains an addition to therapy — not a replacement for it.
MNMichał Nowak11 min
August 27, 2026
GuidesVitamin D and Multiple Sclerosis — Does Supplementation Reduce Relapse Risk?
Low vitamin D levels and limited sun exposure have long been linked in observational studies to a higher risk and prevalence of multiple sclerosis (MS). This led researchers to ask whether vitamin D supplementation could actually reduce the number of disease relapses or slow the accumulation of disability in people already living with MS. A 2021 meta-analysis of nine randomized trials gave an answer that will surprise many — and shows just how large the gap can be between a strong observational association and a proven effect of intervention.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesExercise and Depression — What Does the Cochrane Review Show?
"Exercise helps with depression" is one of those recommendations you hear everywhere — from the doctor's office to social media. A Cochrane review covering 39 studies and more than two thousand participants does confirm a moderate effect of exercise on depression. But that same review contains a second, far less frequently cited number: when the analysis was restricted to only the most methodologically rigorous studies, the effect nearly disappeared. This is one of the best available lessons in how to read meta-analyses critically — and why the quality of studies, not just their number, determines the strength of a conclusion.
MNMichał Nowak11 min
August 27, 2026
GuidesL-theanine, Stress, and Anxiety — What Does a Clinical Trial Actually Show?
L-theanine, an amino acid best known as a mellowing companion to caffeine, is increasingly marketed on its own as a natural way to cope with stress and anxiety. A randomized, double-blind trial using magnetoencephalography (MEG) did find measurable changes in stress response and brain activity — but it's worth understanding exactly what was measured, in whom, and what these results do not prove about clinical anxiety disorder.
JWJulia Wiśniewska11 min
August 27, 2026
GuidesCognitive Behavioral Therapy for Insomnia (CBT-I) — What Does a Meta-Analysis Show?
When sleep falls apart, the simplest reflex is to reach for a sleeping pill. Yet for years, international sleep medicine guidelines have pointed to a completely different approach as the first-line treatment for chronic insomnia — cognitive behavioral therapy for insomnia (CBT-I). A large meta-analysis covering 87 randomized trials and over 6,000 participants shows why that recommendation isn't arbitrary.
JWJulia Wiśniewska11 min
August 27, 2026
GuidesProtein and Resistance Training vs. Sarcopenia — What Does the Research Review Show?
Sarcopenia — the progressive, age-related loss of muscle mass and strength — is often treated as an inevitable part of aging that little can be done about. A large umbrella review, covering 41 systematic reviews and roughly 4,475 primary studies, shows something else: a specific, quantifiable intervention (protein at 1.2 g/kg body weight per day or more combined with resistance training) alongside separate but related data on what actually reduces fall risk in older adults.
MNMichał Nowak11 min
August 27, 2026
GuidesCinnamon and Insulin Resistance — What Does the Meta-Analysis Show?
Cinnamon is one of the most frequently recommended "natural" interventions for insulin resistance — cheap, easy to find, and a kitchen staple for thousands of years. A current meta-analysis of 24 randomized trials does show a significant improvement in glycemic markers in patients with type 2 diabetes, but the evidence itself is more ambiguous than popular headlines suggest — the studies differ in cinnamon species, dose, and duration, and most cinnamon sold in stores (cassia) contains coumarin, a compound relevant to liver safety with long-term, high intake.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesBeetroot Nitrates and Blood Pressure — What Does the Meta-Analysis Show?
Beetroot juice is often recommended as a natural way to lower blood pressure — thanks to its naturally high content of inorganic nitrates, which the body converts into nitric oxide, a potent vasodilator. A meta-analysis of 16 small crossover trials does show a statistically significant drop in systolic blood pressure, but the mechanism itself is more complex and dependent on individual factors than the headlines suggest — and most of the trials covered very short intervention periods.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesAlpha-Lipoic Acid and Diabetic Neuropathy — What Does the Meta-Analysis Show?
Diabetic neuropathy — pain, tingling, and numbness in the feet resulting from nerve damage caused by chronically elevated glucose — affects a substantial share of people with long-standing diabetes. Alpha-lipoic acid, a potent antioxidant, is one of the few supplements with a meta-analysis of several randomized trials showing a real improvement in symptoms. There is, however, an important detail that's easy to overlook: nearly all of this evidence concerns intravenous infusions in a clinical setting, not capsules bought at a pharmacy.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesVitamin C and Gum Disease — Does Supplementing or Rinsing With It Really Help?
The link between vitamin C and gum health is one of the oldest facts in medicine — scurvy, a disease caused by severe deficiency of this vitamin, has been associated with bleeding, swollen gums for centuries. But does that historical fact mean adding vitamin C to a mouthwash used alongside standard periodontal treatment gives an extra benefit to people who aren't deficient? A randomized trial from 2025 in 60 patients tested exactly that question — and the answer is more restrained than the packaging of vitamin C mouthwashes would suggest.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesProbiotics and Women's Intimate Health — What Does the Meta-Analysis Show?
Bacterial vaginosis and vulvovaginal candidiasis are two completely different conditions that are often confused, and most women deal with one or the other at some point in their lives. A large 2024 meta-analysis covering 35 studies and more than 3,700 patients checked whether probiotics genuinely help treat and prevent recurrence of both conditions — and found clearly better outcomes, though the authors themselves note that more solid research is still needed.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesExercise and Chronic Low Back Pain — What Does the Cochrane Review Show?
Chronic low back pain is one of the most common reasons for doctor visits and sick leave worldwide. For decades, the standard advice was rest — today, the largest available body of evidence, covering 249 clinical trials, shows the opposite: movement, not immobilization, is the approach backed by the strongest evidence. We check exactly what the 2021 Cochrane review found, how large the effect is, and for whom exercise isn't the first step.
MNMichał Nowak11 min
August 27, 2026
GuidesOmega-3 and Rheumatoid Arthritis — What Does the Meta-Analysis Show?
Rheumatoid arthritis (RA) is an autoimmune disease, completely different from the mechanical cartilage wear seen in osteoarthritis. A 2024 meta-analysis of 18 trials examined whether omega-3 supplementation actually helps RA patients — and revealed a picture more nuanced than a simple "yes, it's anti-inflammatory": a clear improvement in tender joint count, but no statistically significant improvement in standard inflammation markers.
PZdr Piotr Zieliński11 min
August 27, 2026
GuidesBiotin and Hair Loss — Does Supplementation Actually Help?
Biotin is one of the best-selling "hair" supplements — marketed as a universal fix for anyone, regardless of the cause of hair loss. The only systematic review on the topic shows something different: evidence for biotin's effectiveness applies almost exclusively to people with an actual, confirmed deficiency of this vitamin — and that deficiency is rare in developed countries on a normal diet. We check what's actually been shown, who supplementation might help, and who it likely won't help at all.
AKdr Anna Kowalczyk11 min
August 27, 2026
GuidesBiotin and Brittle Nails — What Did the Classic Study Show?
Brittle, splitting nails (onychoschizia) are a common cosmetic problem, and biotin has for decades been cited as one of the few supportive treatments with real, if modest, scientific backing. The classic 1990 Colombo et al. study, using electron microscopy, showed a specific improvement in nail thickness and structure in people taking biotin — though in a very small group of 32 people. That's an interesting contrast with the evidence for biotin in hair loss, which is much weaker — the strength of the evidence for biotin clearly depends on which outcome you're evaluating.
AKdr Anna Kowalczyk11 min
August 27, 2026