Glossary

Biohacking made clear

90 terms you meet in articles, blood results and labels – explained in one or two sentences.

A

acute inflammation: A short, useful inflammatory response that heals wounds and fights infection. Unlike chronic inflammation, it fades once its job is done.
adenosine: A substance that builds up in the brain while awake and increases sleepiness. Caffeine blocks its receptors, masking tiredness without removing it.
adrenaline: The acute alarm hormone. It speeds up the heart, raises blood pressure and opens the airways during fear or hard effort.
aerobic capacity: The body's ability to use oxygen to produce energy, usually expressed as VO2max. Higher capacity goes with healthier ageing.
AMPK: The cell’s energy sensor. Exercise and fasting switch it on, triggering fat burning and mitochondrial renewal.
ApoB: Apolipoprotein B – the number of particles that carry cholesterol into the arteries. A more precise risk marker than LDL alone.
ATP: The cell's energy currency, used to pay for every task. It is produced by the mitochondria.
autophagy: Cellular “clean-up” – the body breaks down and recycles damaged cell parts. Fasting and exercise support it.

B

BDNF: A protein that supports the growth and survival of neurons – a kind of brain fertiliser. Exercise, learning and cold raise it.
biohacking: Deliberate, measurable fine-tuning of your own biology for health, performance and longevity – from the plate to advanced technology.
BPA: A chemical in some plastics and can linings that mimics hormones. Cutting exposure is one of the cheapest steps you can take.

C

CGM: Continuous glucose monitor – a small skin sensor that reads blood sugar every few minutes and shows how you react to food.
circadian rhythm: The body’s internal 24-hour clock that governs sleep, hormones and digestion. Morning light sets it.
collagen: The most abundant protein in the body, holding together skin, tendons, cartilage and blood vessels. Production falls with age.
cortisol: The main stress hormone. It should peak in the morning and be lowest at night – a disrupted rhythm harms sleep and metabolism.
creatine: A compound that quickly replenishes ATP in muscles and the brain. Cheap, well studied and safe.

D

dopamine: The neurotransmitter of motivation and reward anticipation. Quick hits (phone, sugar) drain it.

E

endocrine disrupt: Substances that mimic or block hormones, such as BPA, phthalates and some pesticides.
endorphins: The body's own opioids. They dampen pain and lift mood, for example during running or laughter.
epigenetic: Mechanisms that switch genes on and off without changing DNA. Diet, sleep, stress and exercise shape them.
excitotoxi: Damage to neurons from excess glutamate, which lets too much calcium flood into the cells.

F

ferritin: The protein that stores iron. It shows your iron reserves – low ferritin causes fatigue even with normal haemoglobin.
fT3: Thyroid hormones: T4 is the storage form, T3 the active one. In blood tests, look at the free values (fT3, fT4).

G

GABA: The main calming neurotransmitter – the nervous system's brake. Alcohol boosts it briefly but unsettles the system long term.
ghrelin: The hunger hormone. It rises before meals and after poor sleep, pushing towards overeating.
glucagon: A pancreatic hormone that raises blood sugar when it drops. It is the counterpart of insulin.
glutathione: The strongest antioxidant inside cells. The body makes it itself but needs sulphur, glycine and cysteine from food.
glyc:aemic index: Shows how fast a food raises blood sugar compared with pure glucose. Individual responses differ, though.
glyc:aemic load: The glycaemic index adjusted for a real portion, which makes it more useful in daily life.
glycation: Sugar sticking spontaneously to proteins and fats. It stiffens vessels, ages skin and damages nerves; HbA1c reflects it.
glymphatic: The brain's waste-clearing system, most active during deep sleep.
GrimAge: A second-generation epigenetic clock that uses DNA methylation in blood to estimate biological age and mortality risk.

H

HbA1c: Glycated haemoglobin – your average blood sugar over the last 2–3 months.
HIIT: High-intensity interval training – short all-out bursts alternated with rest. Effective, but not for every day.
hippocamp: The brain region for memory and orientation. It shrinks with long-term stress and insomnia.
HOMA-IR: An insulin resistance index calculated from fasting glucose and insulin. A value above 2 is a warning sign.
homocysteine: An amino acid that damages blood vessels and the brain when high. Vitamins B12, B6 and folate lower it.
hormesis: The principle that a small dose of stress makes the body stronger – e.g. sauna, cold, fasting or training.
HRT: Hormone replacement therapy, most often in menopause. It eases symptoms and may protect bones and heart.
HRV: Heart rate variability – tiny differences between heartbeats. Higher HRV means better recovery and stress resilience.
hs-CRP: C-reactive protein – a marker of inflammation. The high-sensitivity test (hs-CRP) also detects silent chronic inflammation.

I

IgA: The main antibody in saliva and mucous membranes – the first line of defence between the body and the outside world.
insulin resistance: A state in which cells respond poorly to insulin, so the body must produce more. It precedes type 2 diabetes by years.
insulin! resistance: A pancreatic hormone that moves sugar from the blood into cells and decides where energy goes. Persistently high insulin is a warning sign.

K

ketosis: A state in which, with few carbohydrates, the body burns fat and makes ketones as an alternative fuel.
klotho: A protein dubbed the 'longevity hormone'. Higher levels are linked to better memory and lower risk of age-related disease.

L

lactate: A product of intense effort. It is not waste but a full-value fuel for the heart and brain.
LDL: 'Bad' cholesterol. It is risky mainly when oxidised; ApoB is a more accurate marker.
leptin: The satiety hormone by which fat tissue tells the brain that reserves are sufficient. In obesity the brain stops responding.
Lpa: Lipoprotein(a) – a genetically determined particle that raises heart attack risk. Measuring it once in a lifetime is enough.

M

melatonin: The darkness hormone that tells the body it is time to sleep. Blue light from screens suppresses it.
methylfolate: The active form of folate. People with an MTHFR gene variant handle it better than synthetic folic acid.
microbiome: Trillions of gut bacteria that influence digestion, immunity, mood and weight.
microplastics: Plastic fragments under 5 mm, already found in blood, brain and placenta. Main sources are bottled water and heating food in plastic.
mitochondri: Tiny “power plants” in cells that turn food and oxygen into energy (ATP).
mTOR: The main “growth switch” in cells. Protein and insulin activate it; alternating growth and rest is key to longevity.

N

NAD: A molecule needed for energy production and DNA repair. Levels fall with age.
NREM: The two main sleep stages: deep NREM restores the body, dream-rich REM serves memory and emotional processing.
NSDR: 'Non-Sleep Deep Rest' – 10–20 minutes of guided relaxation that can stand in for a short nap.

O

omega-3 index: The share of omega-3 fatty acids in red blood cell membranes. Optimal is above 8%.
oxidative stress: An excess of free radicals over antioxidants that damages cells and speeds up ageing.
oxytocin: The hormone of trust and bonding, released by hugs, touch, childbirth and breastfeeding.

P

PFAS: Perfluorinated 'forever chemicals' from non-stick pans, water-proofing and some paper packaging. They take centuries or longer to break down.
phthalates: Plastic softeners found in packaging, cosmetics and fragrances. They can lower testosterone and may hide behind the word 'parfum'.
PPAR:-gamma: A cell receptor that controls fat storage and the inflammatory response. Some drugs and omega-3s activate it.
prebiotics: Fibres that feed beneficial gut bacteria – found in onion, garlic, leek and artichoke.
probiotics: Live beneficial bacteria in food or supplements – such as yoghurt, kefir, sauerkraut and kimchi.
prolactin: A hormone released after orgasm and childbirth that brings calm. When chronically high it lowers libido and testosterone.

R

resveratrol: A red-grape polyphenol that activates sirtuins. Supplements contain many times more than a glass of wine.

S

sarcopenia: Gradual age-related loss of muscle. Inactivity, low protein and hormonal changes speed it up.
SCFA: Short-chain fatty acids made by gut bacteria from fibre. The best known, butyrate, feeds colon cells.
serotonin: A neurotransmitter linked to calm, satiety and stable mood. Most of it is made in the gut.
SHBG: A protein that binds sex hormones. The more SHBG, the less free (active) testosterone and oestrogen.
sirtuins: A family of enzymes that protect DNA and influence the pace of ageing. Fasting and exercise activate them.
spermidine: A molecule that supports autophagy. Wheat germ, mushrooms and fermented natto are rich sources.

T

telomere: Protective “caps” at the ends of chromosomes. They shorten with each cell division – a marker of ageing.
testosterone: The main male sex hormone, also present in smaller amounts in women. It affects libido, energy, muscle and mood.
thrombosis: A blood clot in a vessel. Long sitting, inflammation and some inherited clotting disorders raise the risk.
trans fats: Fats created by partially hardening oils – the most harmful type of fat. Labels reveal them as 'partially hydrogenated'.
triglycerides: The main storage form of fat in the blood. High values often point to too much sugar and alcohol.
TSH: The pituitary hormone that instructs the thyroid. The biohacking optimum is roughly below 2.5.

U

ultra-processed: Group 4 of the NOVA classification: industrial mixtures with emulsifiers, syrups, flavourings or colours that a normal kitchen would not make.

V

vagus nerve: The longest nerve in the body, linking the brain with the heart, lungs and gut. Good vagal tone means faster recovery.
VO2smax: The maximum amount of oxygen your body can use. One of the strongest predictors of lifespan.

W

Wim Hof: A method combining specific breathing (hyperventilation and breath holds) with cold exposure.

X

xenobiotics: Substances foreign to the body, such as drugs, toxins and pollution. The liver converts them into forms it can excrete.

Y

yoga nidra: 'Yogic sleep' – guided relaxation lying down, one of the most effective ways to recharge quickly during the day.

Z

zinc: A trace mineral needed for immunity, healing and testosterone production. Long-term high doses deplete copper.
zone 2: Low-intensity exercise at which you can still talk. It trains mitochondria and fat burning best.
zonulin: A protein that controls the permeability of the gut wall. High levels are linked to 'leaky gut' and autoimmunity.

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