The supplement Library.

Organic compounds you must consume because the body can't synthesise them. Most people get the broad spectrum from food and only need to think about the handful where modern life creates predictable shortfalls — vitamin D (sunlight), B12 (animal foods), folate (methylation), and the few B's that get burned through under stress.

Inorganic elements the body uses for structural and catalytic functions. The big four to think about supplementing are magnesium, zinc, iodine, and (in menstruating women or vegetarians) iron. The rest are usually covered by a varied diet, though boron, lithium, and silicon have niche cases worth knowing about.

The building blocks of every protein in the body, plus the modified forms (NAC, TMG, creatine, carnosine) the body uses for specific tasks. This is one of the highest-leverage supplement categories — glycine and NAC together reverse some markers of biological aging; creatine is the most-studied performance supplement in history; theanine and tyrosine produce real cognitive and mood effects within hours.

Powders, shakes and bars — food in a convenient format, judged on protein per serving, purity and cost.

Lipid-based supplements — primarily the long-chain omega-3s (EPA, DHA), but also GLA, the medium-chain triglycerides, the short-chain fatty acid butyrate, and the newer C15:0. Most modern diets are heavy in pro-inflammatory omega-6 and light in omega-3; rebalancing that ratio is the single most leveraged dietary intervention here.

Plant pigments and other compounds that quench free radicals, modulate inflammation, and (in the case of resveratrol, fisetin, quercetin) activate longevity-related signalling pathways. Most of the action here is in chronic, low-grade effects — measurable in inflammatory markers and oxidative stress over months, rather than felt acutely.

Molecules the body uses to run energy production, redox chemistry, and DNA repair. CoQ10 is the headliner; the NAD+ precursors (NMN, NR, niacinamide) sit underneath, and PQQ, urolithin A, and α-KG support mitochondrial biogenesis and quality control. This category becomes more important with age — most of these decline measurably from 40 onward.

Compounds that influence the body's hormone systems — direct precursors like DHEA and pregnenolone that the body converts as needed, and modulators like DIM and calcium D-glucarate that shift how estrogens are metabolised and excreted. This is the category where 'test before supplementing' applies most strongly — these things change your hormone levels, sometimes in unwanted directions.

Plant extracts with bioactive effects — adaptogens, nootropics, hormone modulators, sleep aids, and traditional medicine staples brought into modern dosing. Quality varies wildly here; standardised extracts (KSM-66, Meriva, Sensoril, etc.) are worth paying for. Sub-grouped below by what they're commonly used for, but each one is filed under TYPE = herb regardless.

Functional / medicinal mushrooms — concentrated extracts of species used for thousands of years in East Asian medicine and now backed by a growing body of modern trial evidence. Each species has its own personality: lion's mane for brain, reishi for sleep and immune calm, cordyceps for energy and lung function, chaga for antioxidants. Form matters: dual-extracts from fruiting body beat plain mycelium-on-grain by a wide margin.

Live bacteria, the fibres that feed them (prebiotics), and the immune-supportive proteins (lactoferrin, colostrum) that build a healthy gut ecosystem. Effects are strain-specific: a study showing one Lactobacillus rhamnosus strain works for traveller's diarrhea says nothing about a different L. rhamnosus product. The biggest wins are during/after antibiotics, in IBS, and for specific targeted conditions.

Proteolytic and digestive enzymes that work on two distinct fronts. With food, they help break down what you eat — useful in pancreatic insufficiency, low stomach acid, or just heavy meals. Between meals (on empty stomach), proteolytic enzymes like bromelain, serrapeptase, and nattokinase are absorbed systemically and act on inflammation, fibrin, and scar tissue. Same enzymes, different jobs, different timing.

Large sugar-based molecules that build the body's structural matrix — joint cartilage, synovial fluid, skin hydration, gut mucus. The classic joint stack (glucosamine + chondroitin) lives here, alongside hyaluronic acid (for skin and joints) and UC-II (a different mechanism — immune tolerance rather than building blocks). Effects are slow to build but accumulate over months.

Nutrient-dense whole-food supplements from algae, sea vegetables, and bee products. Spirulina and chlorella have the strongest evidence — both for general nutrition and for chlorella's heavy-metal binding. The newer entrants (sea moss, marine phytoplankton) are heavier on marketing than trial data. Quality matters significantly here: poorly-sourced algae can be contaminated with heavy metals or microcystins.

Active ingredients applied to skin rather than ingested. Retinoids and topical vitamin C have the deepest evidence base; the newer NAD-precursor and copper-peptide entries are still building their case. The skincare industry runs on hype; this section focuses on what the trial data actually supports. Layer wisely — too many actives at once compromises the skin barrier.

A small but distinct chemical category — small nitrogen-containing molecules that modulate neurotransmitter and cellular signalling. Spermidine triggers autophagy (longevity). Theacrine is a caffeine cousin without the tolerance. PEA gives an acute mood lift. DMAE and agmatine round out the niche. Often the strongest acute effects in the entire supplement space — handle with proportional respect.