Creatine

Creatine's mechanism has nothing to do with cartilage, and this entry won't pretend otherwise. Phosphocreatine buffering raises training quality, which augments resistance-training gains in lean mass and strength — and quadriceps strength is a known protective factor for knee-OA symptoms and function. Any joint benefit runs through muscle.

The direct knee-OA trials

Neves 2011 (n=24 postmenopausal women with knee OA, 20 g/day for a week then 5 g/day, 12 weeks, both arms doing supervised lower-limb resistance training): physical function improved only with creatine — timed-stands went from 15.7 to 18.1 reps versus no change on placebo (P=0.004) — along with WOMAC function and stiffness subscales, lower-limb lean mass, and quality of life. The honest asterisk: pain improved in both groups. That was the training working, not the creatine.

Osama 2025 (n=40, creatine plus physical therapy versus placebo plus identical therapy, 4 weeks): greater improvements in VAS pain, KOOS, isometric strength, and fall-risk measures with creatine. Short, small, multiple co-interventions, not yet replicated.

That is the entire direct evidence base: 64 randomized participants across two single-centre trials.

Where it did nothing

The pattern across the null results is instructive. Around total knee arthroplasty (n=37, dosed before and after surgery), creatine produced no benefit for body composition, strength, or recovery — a catabolic peri-operative window likely swamps any supplement. In rheumatoid arthritis without a training program (n=40), creatine added half a kilogram of lean mass but no strength or objective function — muscle mass without training does not become function.

The consistent reading: creatine helps when paired with progressive resistance training and does little without it.

The indirect base

The meta-analysis behind the "stronger muscle protects the joint" logic pooled 22 RCT arms (n=721 older adults): creatine during resistance training added about 1.37 kg of lean tissue and modestly more upper- and lower-body strength than training alone. Those participants were generally healthy older adults, not OA patients, and no joint outcomes were measured — it anchors the mechanism, not the OA claim.

Dose & practical notes

Trial-tested regimens: 20 g/day loading for 5–7 days then 3–5 g/day, or simply 3–5 g/day throughout. Expect roughly 1–2 kg of scale-weight gain from intramuscular water. If you are not doing progressive resistance work, the trial record gives you little reason to expect anything.

Safety

Creatine monohydrate at 3–5 g/day has an unusually deep safety record; controlled data do not support kidney-damage claims in healthy users, including older adults — though the ISSN position stand making that case has authors with industry consulting ties. Use medical supervision with pre-existing renal disease. Serum creatinine rises benignly (it is a creatine metabolite) and can be misread on blood panels; GI upset occurs at large single doses.

What I take from it

Creatine is the rare supplement here whose best evidence is honest about its route: it makes rehab and strength training work better, and strength is one of the few interventions with real evidence for painful knees. Take it as a training adjunct or not at all.