dr Piotr Zieliński

Vitamin D3

Functionally it acts like a steroid hormone — deficiencies are widespread in Poland, especially during autumn and winter.

Magnesium

A cofactor for more than 300 enzymatic reactions — essential for neuromuscular function, sleep and energy metabolism.

Cortisol

The main stress hormone — essential for short-term survival, but problematic when chronically elevated.

Testosterone

The primary anabolic hormone — its natural level depends heavily on sleep, resistance training, body composition and fat mass.

Berberine

A plant alkaloid sometimes called 'nature's metformin' — studies show a meaningful effect on blood glucose, though it doesn't replace pharmacological treatment.

Which Magnesium Should You Choose? Glycinate, Citrate or Lactate — Comparing the Forms

The supplement shelf can be overwhelming: glycinate, citrate, lactate, oxide, chelate... We compare the most popular forms of magnesium for absorption, price, and what each one is actually best suited for.

18 sierpnia 2026

Vitamin D3 or D3 + K2? What the Research Says About Combining Them

Vitamin D3 is the most commonly supplemented nutrient in Poland, and more and more products are now pairing it with vitamin K2. We check whether that combination is actually backed by science, or mostly a marketing hook.

18 sierpnia 2026

Creatine

One of the most thoroughly studied supplements in the world — supports strength, muscle mass and, according to newer research, cognitive function.

Intermittent Fasting (IF)

An eating pattern based on cycles of eating and fasting, e.g., 16:8 — the evidence is solid for weight reduction, less conclusive for effects independent of caloric deficit.

Mediterranean Diet

The best-studied eating pattern for cardiovascular health and longevity.

Strength Training

One of the single strongest predictors of healthy aging — it shapes muscle mass, bone density, and insulin sensitivity.

Melatonin

The hormone that governs your circadian rhythm — as a supplement it works better at resetting the body clock than as a classic 'sleeping pill.'

Sauna (Thermal Heat Therapy)

Regular sauna use is linked in cohort studies to lower cardiovascular mortality risk — the strongest data comes from Finland.

Probiotics

The effectiveness of probiotics depends heavily on the specific strain and indication — there's no single universal 'best probiotic'.

NMN (Nicotinamide Mononucleotide)

An NAD+ precursor intensively studied in the context of cellular aging — human data are still early, despite huge market popularity.

Resveratrol

The red-grape polyphenol famed as a 'sirtuin activator' — but its bioavailability in humans is very low, which limits the practical relevance of many striking test-tube results.