CTX (C-Telopeptide)

Specialist

also beta-crosslaps, ctx-1

What it isCTX is a fragment of type 1 collagen released into blood when osteoclasts (bone-resorbing cells) break down bone matrix.

DoesReports the rate of bone resorption.

GoodMid-range CTX with adequate bone formation markers signals balanced remodeling.

BadHigh CTX signals accelerated bone loss in osteoporosis. Low CTX confirms response to bisphosphonate therapy but if suppressed too low may track atypical fracture risk.

Standard

Men 87–1200 pg/mL; women premenopausal 25–573, post 104–1008 pg/mL.

Optimal

250–500 pg/mL men, 150–400 pg/mL premenopausal women (lower is good within range)

Modifiers

Diurnal — highest overnight, fast for accurate AM measurement; rises after fracture.

How to optimize

Lifestyle: Weight-bearing and resistance training; avoid prolonged inactivity.
Diet: Adequate protein and calcium.
Supplements: Vitamin D3, vitamin K2 MK-7, calcium from food, magnesium glycinate.
Peptides: —
Drugs: Bisphosphonates, denosumab, raloxifene suppress resorption.

within Bone Density