Supplement Forms Compared

For creatine the honest answer is that the cheapest form is the best form. Creatine monohydrate has hundreds of studies behind it and is the reference every other form is measured against — and in head-to-head trials HCL, Kre-Alkalyn and ethyl ester have never beaten it. Micronised monohydrate and Creapure are still just monohydrate, ground finer or purity-certified, so they are perfectly good; you are only paying for mixability or a brand stamp. Anything sold as a next-generation upgrade is almost always a worse deal for the same effect.

• Best BuyMonohydrate — The most-studied form by a mile, cheap, and it works. This is the default answer.
• Best BuyCreapure (monohydrate) — Same molecule, a German purity brand. A fair small premium if you want the certification — no extra effect.
• Best BuyMicronised — Just monohydrate ground finer so it mixes better. Same results, slightly nicer to drink.
• SituationalHydrochloride (HCL) — More soluble, so a smaller scoop — but no proven advantage over monohydrate, at a higher price.
• SkipKre-Alkalyn / buffered — Marketed as "no bloat, no loading". Head-to-head studies show it is no better than monohydrate, for more money.
• SkipEthyl ester — Breaks down to creatinine in the gut; research shows it is worse than plain monohydrate.

The three whey forms differ mostly in how much they are filtered, not in how well they build muscle — total daily protein is what matters. Concentrate gives you the most protein per pound and suits most people. Isolate is more filtered to around 90% protein with very little lactose, so it is the right pick if concentrate leaves you bloated or you want the leanest macros. Hydrolysate is pre-broken-down for faster absorption, but the real-world difference is tiny and rarely worth the price jump.

• Best BuyConcentrate — Best protein-per-pound. 70-80% protein with a little more carbs and fat — fine for almost everyone.
• SituationalIsolate — More filtered, ~90% protein, very low lactose. Worth it if concentrate bloats you or you want leaner macros.
• SituationalNative whey — Filtered from milk rather than cheese-making. Premium and marginal — nice, not necessary.
• SkipHydrolysate — Pre-digested for slightly faster absorption. Costs a lot more for a benefit you will not feel.

Magnesium forms differ hugely in how much your body actually absorbs. Glycinate (bisglycinate) is well absorbed and easy on the stomach, which makes it the popular pick for relaxation and sleep. Citrate is also well absorbed and cheaper, with a mild laxative effect that can be a bonus or a nuisance depending on you. Oxide, the form in most cheap tablets, is very poorly absorbed and mostly acts as a laxative, so a high number on the label does not mean you get much magnesium.

• Best BuyGlycinate / bisglycinate — Well absorbed and gentle on the gut. The go-to for relaxation, sleep and daily topping-up.
• Best BuyCitrate — Well absorbed and cheap. Mildly laxative, which is a plus if constipation is the issue.
• SituationalMalate — Absorbable and popular for daytime use; a fine choice, just usually pricier than citrate.
• SituationalL-threonate — Marketed for the brain. Genuinely expensive and the human evidence is still thin — a niche buy.
• SkipOxide — Cheap filler in most tablets but very poorly absorbed — mostly a laxative, not a magnesium top-up.

Vitamin D comes as D2 (ergocalciferol) and D3 (cholecalciferol), and they are not equal. D3 is the form your body makes from sunlight and it raises and maintains blood levels more effectively than D2, which is why D3 is the standard recommendation. Pairing D3 with K2 is a popular, sensible combination for directing calcium toward bone, though it is an optional upgrade rather than a must. Vegans can now get D3 from lichen, so D2 is rarely the best choice.

• Best BuyD3 (cholecalciferol) — The form your skin makes from sunlight. Raises and holds blood levels more effectively than D2.
• Best BuyD3 + K2 — A sensible pairing; K2 helps direct calcium to bone. A reasonable upgrade, not essential.
• SkipD2 (ergocalciferol) — Plant-derived and used in some prescriptions, but weaker at raising blood levels. Only pick it if you need vegan and cannot get vegan D3.

L-citrulline and citrulline malate both work for blood flow and pumps — the catch is the dose, not the form. The target is 6–8 g L-citrulline, which is about 9–12 g citrulline malate (2:1) or 12–16 g (1:1), because malate is citrulline bonded to malic acid. The common mistake is buying by headline grams without checking how much is actually citrulline, which is exactly how many pre-workouts under-deliver.

• Best BuyL-citrulline (pure) — Straight citrulline. Aim for 6-8g. Cleaner label maths than the malate blend.
• Best BuyCitrulline malate 2:1 — Citrulline bonded to malic acid; the form in most pump studies. The target is 6–8 g L-citrulline, which is about 9–12 g citrulline malate (2:1) or 12–16 g (1:1).
• SituationalCitrulline malate 1:1 — Half the ratio, so you need even more powder for the same citrulline. Check the label carefully.

Like magnesium, zinc absorption depends heavily on the form. Picolinate and bisglycinate are well absorbed and make good everyday choices, while citrate and gluconate are reasonable and cheaper. Oxide is the cheap filler form and is poorly absorbed, so it flatters the label more than your blood levels. One caution that applies to every form: sustained high-dose zinc can deplete copper, so keep doses sensible rather than mega.

• Best BuyPicolinate — Well absorbed and widely available. A safe default for topping up zinc.
• Best BuyBisglycinate — Also well absorbed and gentle on an empty stomach.
• SituationalCitrate — Decent absorption and cheap — a perfectly reasonable budget choice.
• SituationalGluconate — The common lozenge form. Fine, absorption is middling.
• SkipOxide — Cheap and poorly absorbed — high on the label, low in your bloodstream.

With ashwagandha the form that matters is standardisation, not brand loyalty. KSM-66 is a root-only extract with the largest bank of human trials for stress, sleep and strength, which makes it the safest evidence-based choice. Sensoril is a root-and-leaf extract standardised to a higher withanolide content and studied more for stress and sleep, usually at smaller doses. Plain root powder is not standardised, so you cannot know the active content, and any extract that hides its withanolide percentage should be treated the same way.

• Best BuyKSM-66 — A standardised root extract with the most human trials for stress and strength. The default evidence-based pick.
• SituationalSensoril — A root-and-leaf extract standardised higher; studied more for stress/sleep, often at lower doses.
• SituationalGeneric standardised root extract — Fine if it states the withanolide percentage and dose — just less directly studied than the branded ones.
• SkipPlain root powder — Unstandardised, so the active content is a guess. You cannot dose it reliably.

For fish oil the headline number should be the combined EPA and DHA per serving, not the total "fish oil" milligrams, because a big capsule can hide a small omega-3 dose. Among forms, the natural triglyceride (rTG) form is absorbed a little better, while the cheaper ethyl ester form is slightly lower but perfectly usable when taken with a fatty meal. Krill oil is well absorbed but delivers relatively little EPA and DHA per capsule for the price, so it works out expensive per gram of actual omega-3.

• Best BuyTriglyceride (rTG/natural) — The natural form; absorbed slightly better. Look for high EPA+DHA per capsule, not just "fish oil mg".
• SituationalEthyl ester (EE) — Cheaper and concentrated; absorption is a touch lower but fine taken with a fatty meal.
• SituationalKrill oil (phospholipid) — Well absorbed but low total EPA/DHA per capsule at a high price — you pay a lot per gram.
• SituationalCod liver oil — Also carries vitamins A and D, so watch total vitamin A if you take a lot.

Curcumin, the active compound in turmeric, is famously badly absorbed on its own, which is the whole story with this supplement. Adding piperine from black pepper dramatically increases how much reaches your bloodstream, and it is the cheapest effective fix. Specialised delivery forms such as phytosome (Meriva) or liposomal curcumin achieve even higher absorption and are well studied, at a higher price. A plain turmeric capsule with no enhancer is the one form to avoid, because most of it simply passes through.

• Best BuyCurcumin + piperine — Black-pepper extract sharply raises absorption. The cheapest way to make curcumin actually work.
• Best BuyPhytosome (Meriva) / liposomal — Formulated for far higher absorption; more expensive but well studied.
• SkipPlain turmeric powder — Very poorly absorbed on its own. Great in cooking, weak as a supplement without a helper.

Caffeine anhydrous is simply dried caffeine, and because it is precise and cheap it is the form used in most performance studies — an effective dose is around 3mg per kilo of bodyweight before training. Natural sources like coffee and green tea work identically; you just have less control over the exact dose. Blended forms such as di-caffeine malate or slow-release caffeine are marketed for smoother, longer-lasting energy with less of a crash, which some people like, but the effect is modest for the extra cost.

• Best BuyAnhydrous — Dried caffeine powder — precise, cheap and the form used in most performance research.
• SituationalNatural (coffee/green tea) — Perfectly good; the dose is just less exact than a measured capsule.
• SituationalDi-caffeine malate / slow-release — Marketed for smoother, longer energy. Pleasant for some, but a small premium for a modest effect.

Collagen peptides and gelatin are the same protein at different processing stages: hydrolysed peptides are broken into small pieces that dissolve in cold drinks and absorb easily, which is why they are the convenient default. Gelatin is less processed, only dissolves in hot liquid and sets as it cools, so it is cheaper but fiddlier. Undenatured type II collagen (UC-II) is a different, low-dose product aimed specifically at joint tolerance rather than general collagen supply. Taking collagen with vitamin C supports the body making its own collagen.

• Best BuyHydrolysed peptides — Broken into small peptides so it mixes into anything cold and absorbs readily. The default for skin and joints.
• SituationalGelatin — The same collagen, less processed; only dissolves in hot liquid and gels when cool. Cheaper, less convenient.
• SituationalUndenatured type II (UC-II) — A different, low-dose approach aimed specifically at joints — not a general collagen top-up.

For most people the difference between B12 forms is smaller than the internet suggests. Methylcobalamin is a ready-to-use active form and a popular pick, particularly among vegans. Cyanocobalamin is cheap, very stable and readily converted by the body, which is why it appears in most large clinical studies. Unless you have a specific medical reason, either corrects a dietary shortfall; genuine B12 deficiency from absorption problems is a medical issue that may need injections, and that is a conversation for a clinician.

• Best BuyMethylcobalamin — A ready-to-use active form. Popular choice, especially for vegans topping up B12.
• SituationalCyanocobalamin — Cheap, extremely stable, and your body converts it fine. The form used in most large studies.
• SituationalAdenosyl / hydroxocobalamin — Other active forms; perfectly good, just less common on shelves.