Every bone health word, in plain English.
The words your doctor, your scan report and our lessons use. Each one tells you why it matters for your bones, how strong the evidence is, and where to go deeper.
Start with these
A T-score shows how your bone density compares to a healthy young adult, measured in standard deviations, and it's…
Osteopenia means your bone density, as measured by a DEXA scan, is lower than average but not as low as osteoporosis…
Osteoporosis is a condition where bone breakdown outpaces bone building, causing bones to become thinner, more…
Bone mineral density (BMD) measures how much mineral is packed into your bones, usually estimated with a DEXA scan,…
A DEXA scan is a low-radiation X-ray test that measures how much mineral is in your hip and spine bones, giving you…
Osteocytes are the most common bone cells. They used to be bone-builders but got trapped inside bone tissue, where…
Wolff's Law says your bones adapt to the loads you put on them, getting stronger with use and losing density when…
Sarcopenia is the gradual loss of muscle mass and strength that comes with aging, and it's closely tied to bone health.
Vitamin D is a nutrient that helps your gut absorb calcium so it can be used to build and maintain bone.
A fragility fracture is a broken bone caused by a fall or bump that normally wouldn't break a healthy bone, often at…
Measuring bone
A 25-hydroxy vitamin D test is a blood test that checks how much vitamin D you have in your body, which is important…
Bone mineral density (BMD) measures how much mineral is packed into your bones, usually estimated with a DEXA scan,…
CTX is a blood test marker that shows how fast your body is breaking down old bone right now, acting like a…
A DEXA scan is a low-radiation X-ray test that measures how much mineral is in your hip and spine bones, giving you…
The femoral neck is the angled part of bone joining your hip ball to your thigh bone shaft, and it's the most common…
FRAX is a free online tool that calculates your 10-year probability of having a major osteoporotic fracture or hip…
Least Significant Change (LSC) is the smallest change in a DEXA scan result that's big enough to count as real,…
Osteopenia means your bone density, as measured by a DEXA scan, is lower than average but not as low as osteoporosis…
Osteoporosis is a condition where bone breakdown outpaces bone building, causing bones to become thinner, more…
P1NP is a blood marker that shows how fast your body is building new bone collagen right now.
A parathyroid hormone (PTH) test measures the amount of PTH in your blood, usually alongside calcium, to help find…
REMS is an ultrasound-based scan that estimates bone density and tissue quality at the spine and hip without using…
A T-score shows how your bone density compares to a healthy young adult, measured in standard deviations, and it's…
Trabecular Bone Score (TBS) is a measurement taken from your spine DEXA image that estimates how well-connected your…
A Z-score compares your bone density to other people your own age and sex, which matters most for younger adults,…
Bone biology
Bone marrow is the soft tissue inside bones where red bone marrow makes your red blood cells, white blood cells, and…
Bone remodeling is the lifelong cycle where cells called osteoclasts remove old bone and osteoblasts build new bone…
Canaliculi are microscopic channels in bone that connect bone cells together and let fluid flow past them, helping…
Type I collagen is the main protein in bone, forming a flexible framework that mineral crystals attach to, giving…
Connexin 43 is a protein that builds tiny tunnels, called gap junctions, letting bone cells pass signals directly to…
Cortical bone is the dense, hard outer layer of bone that forms a protective shell and resists bending and twisting…
Gap junctions are direct tunnels between bone cells that let them share signals instantly, so one cell sensing force…
A Haversian canal is a tiny tunnel running through dense bone that carries blood vessels and nerves to keep the bone…
Hydroxyapatite is the hard mineral crystal, made mostly of calcium and phosphorus, that gives your bones their…
A lacuna is a tiny chamber inside bone where an osteocyte, a mature bone cell, lives and senses the forces placed on…
An osteoblast is a cell that builds new bone by laying down fresh bone matrix, working alongside cells that break…
Osteocalcin is a hormone made by bone that helps regulate blood sugar, muscle energy use, and other body functions…
Osteoclasts are the cells that break down old bone tissue, working alongside bone-building osteoblasts to constantly…
Osteocytes are the most common bone cells. They used to be bone-builders but got trapped inside bone tissue, where…
The periosteum is the thin membrane that covers the outside of your bones, carrying blood vessels and nerves into…
Sclerostin is a protein made by bone cells called osteocytes that blocks new bone formation; less mechanical strain…
Trabecular bone is the spongy, honeycomb-like bone found inside structures like your spine and hip, providing…
How bone adapts
Endosteal resorption is the thinning of bone from the inner surface outward, which widens the hollow space inside…
Integrins are proteins that anchor bone cell extensions to their surrounding canal, letting cells sense mechanical…
Interstitial fluid flow is the movement of fluid through tiny channels in bone that happens when bone bends,…
The lacunar-canalicular system is a network of tiny spaces and channels in bone where fluid moves when bone is…
The mechanostat is Frost's theory that bone acts like a thermostat, removing, maintaining, or building bone…
Mechanotransduction is how bone cells sense physical force and turn it into chemical signals that tell bone to adapt.
Microstrain (µε) is a tiny measure of how much bone bends under force — one millionth of its original length.
Bone modeling is the process where your body adds or removes bone on its surfaces, reshaping it in response to the…
Periosteal expansion is the slight widening of bone that happens on its outer surface as we age, even as the inside…
Piezo1 is a stretch-sensitive channel in bone cell membranes that opens when fluid moves through bone, letting ions…
Strain rate is how quickly a force is applied to bone, not just how much force there is — and faster loading tends…
Wolff's Law says your bones adapt to the loads you put on them, getting stronger with use and losing density when…
Loading & training
Ground reaction force is the push-back force the ground gives your body each time you step or move against it.
Isometric exercise is when your muscle pushes hard against something that doesn't move, like pressing against a…
The LIFTMOR trial was a study showing that supervised, heavy twice-weekly lifting over eight months helped…
Osteogenic loading means applying brief, high, muscle-generated force to your skeleton in a way that's strong enough…
Resistance training is exercise where your muscles work against weight or resistance, like squats, deadlifts, or…
Weight-bearing exercise is any activity, like walking or dancing, where your body supports its own weight against…
Muscle & balance
Balance training is practice that improves your stability and coordination so you're less likely to fall — and falls…
Fall risk is how likely you are to fall, and it matters because falling—not just weak bones—is the most common cause…
The Golgi tendon organ is a sensor in your tendons that detects how much force your muscles are producing and helps…
Irisin is a chemical messenger (myokine) released by working muscles that signals bone-building cells to become active.
Lean mass is mostly your muscle weight — the non-fat part of your body. It's tracked because it's closely linked to…
Myokines are chemical messengers released by working muscle that can signal bone cells, linking muscle activity and…
Myostatin is a molecule made by muscle that slows down growth in both muscle and bone tissue.
Sarcopenia is the gradual loss of muscle mass and strength that comes with aging, and it's closely tied to bone health.
Risk & causes
Advanced glycation end-products (AGEs) are compounds that form when excess sugar damages proteins in the body,…
An atypical femoral fracture is an uncommon break in the shaft of the thigh bone that looks and behaves differently…
Avascular necrosis is when part of a bone dies because it loses its blood supply, which can weaken and eventually…
Bariatric surgery (gastric bypass or sleeve) changes digestion in ways that can speed up bone loss, mainly through…
Bone metastases occur when cancer spreads from elsewhere in the body into bone, disrupting the normal balance…
Celiac disease is an autoimmune condition that damages the small intestine, often reducing absorption of calcium,…
Chronic kidney disease is a long-term decline in kidney function that can disrupt vitamin D activation and the…
Crohn's disease is a digestive condition that inflames and damages the gut lining, which can reduce the body's…
Cushing's syndrome is a condition caused by too much cortisol in the body, which can seriously weaken bones over time.
A fragility fracture is a broken bone caused by a fall or bump that normally wouldn't break a healthy bone, often at…
Glucocorticoid-induced osteoporosis is bone loss caused by steroid medications or high cortisol levels, which weaken…
Goitrogens are natural compounds in foods like broccoli, cabbage, and kale that can interfere with how your thyroid…
A hip fracture is a break at the femoral neck, the narrow part of bone connecting the hip joint ball to the thigh…
Hyperparathyroidism is when overactive parathyroid glands release too much hormone, causing your bones to lose…
Hyperthyroidism is an overactive thyroid gland that speeds up bone remodeling so much that bone-building cells can't…
Inflammatory bowel disease (IBD) covers conditions like Crohn's and ulcerative colitis, where gut inflammation and…
Leaky gut, or intestinal permeability, means the lining of the intestine lets more substances pass through than it…
Lectins are proteins in many plant foods, including beans and grains, that some popular diets blame for inflammation…
Multiple myeloma is a cancer of plasma cells in the bone marrow that disrupts the normal bone rebuilding process,…
Osteogenesis imperfecta is a genetic disorder that causes the body to make fragile collagen, leading to bones that…
Osteomalacia is softening of the bones caused by severe, long-term vitamin D deficiency, which prevents bone from…
Osteonecrosis of the jaw (ONJ) is a rare condition where part of the jawbone loses blood supply and fails to heal,…
Oxalates are natural compounds in foods like spinach and rhubarb that bind calcium in the gut, blocking its…
Paget's disease is a condition where bone remodeling speeds up too much in specific spots, creating new bone that's…
Rheumatoid arthritis is an autoimmune disease that causes chronic joint inflammation, and that same inflammation…
Hormones
Androgen deprivation therapy (ADT) is a prostate cancer treatment that lowers testosterone to very low levels. It's…
An aromatase inhibitor is a medication that blocks the enzyme aromatase, which the body uses to make estrogen. It's…
Bioidentical (or body-identical) hormones are hormones that are structurally identical to the ones your own body…
Cortisol is your body's main stress hormone. When it stays high for a long time, it weakens bone by slowing bone…
Estrogen is a hormone that protects bone by keeping bone-removing cells in check. Falling estrogen, especially at…
Hormone replacement therapy (HRT) replaces oestrogen, often with a progestin, after menopause and has been shown to…
Menopause is when your periods stop and estrogen levels drop sharply, which speeds up bone loss because the cells…
Premature menopause is when periods stop before about age 45, due to primary ovarian insufficiency, ovary removal,…
SHBG is a blood protein that binds testosterone and other sex hormones, controlling how much is "free" and active in…
Testosterone is a male hormone that supports bone formation directly and indirectly, partly by being converted into…
The timing hypothesis is the idea that when a woman starts hormone therapy, relative to her menopause, strongly…
The Women's Health Initiative, or WHI, was a major 2002 study on hormone therapy in postmenopausal women that found…
Medications
Abaloparatide (Tymlos) is a daily injectable medication that stimulates bone-building cells to form new bone, used…
Anabolic bone agents are medications, like teriparatide, abaloparatide, and romosozumab, that stimulate the body to…
Antiresorptive medications, like bisphosphonates and denosumab, slow down the cells that break down old bone,…
Bisphosphonates are osteoporosis medications — like alendronate, risedronate, and zoledronic acid — that slow down…
Corticosteroids like prednisone and dexamethasone are anti-inflammatory medications that, especially with long-term…
Denosumab (Prolia) is a twice-yearly injection that blocks RANKL, a signal osteoclasts need to mature, slowing bone…
A drug holiday is a temporary, prescriber-guided pause from a bisphosphonate medication after several years of use,…
GLP-1 receptor agonists like semaglutide (Ozempic, Wegovy) are diabetes and weight-loss medications that don't seem…
A proton pump inhibitor (PPI) is a medication like omeprazole or pantoprazole that reduces stomach acid to treat…
RANKL is a signal that activates osteoclasts, the cells that break down bone, and it's a key target for some…
Romosozumab (brand name Evenity) is an anabolic osteoporosis medication given by injection that blocks sclerostin, a…
SSRI antidepressants, when used long-term, have been linked to a small increase in fracture risk, which is why bone…
Teriparatide (Forteo) is a daily injected medication that stimulates bone-building cells to form new bone, rather…
Nutrition & supplements
Boron is a trace mineral that helps your body retain calcium and magnesium, two nutrients your bones need.
Calcium is the main building-block mineral in bone, and since your body can't make it, you need to get it from food…
Collagen peptides are an easy-to-absorb form of collagen protein, the main building block that gives bone its…
The gut microbiome-bone axis describes how bacteria living in your gut may influence bone health through effects on…
IGF-1, or insulin-like growth factor 1, is a substance in your body that protein intake stimulates, helping to…
Magnesium is a mineral that helps activate vitamin D and forms part of the actual crystal structure of bone.
Omega-3 fatty acids are healthy fats, found in fish and some plant foods, that may help lower inflammation in the…
Phytic acid is a natural substance in grains, legumes, nuts and seeds that can bind minerals like calcium and iron,…
Phytoestrogens, like soy isoflavones, are plant compounds that weakly mimic oestrogen and are linked to small bone…
Protein intake means getting enough dietary protein to support collagen, the protein that makes up about a third of…
Short-chain fatty acids (SCFAs) are compounds like butyrate, propionate, and acetate that your gut bacteria produce…
Vitamin C is a nutrient your body needs to make collagen, the flexible protein framework that gives bone its toughness.
Vitamin D is a nutrient that helps your gut absorb calcium so it can be used to build and maintain bone.
Vitamin K2 is a nutrient that helps direct calcium into your bones and away from your arteries by activating…
Zinc is a mineral that helps the cells which build new bone, osteoblasts, use the enzymes they need to do their job.
Lifestyle & recovery
Heavy alcohol use directly weakens the cells that build bone and raises your chances of falling and fracturing a bone.
Astronaut bone loss is the fast, uneven loss of bone density that happens in microgravity, mainly in weight-bearing…
Bed rest bone loss is the rapid loss of bone density that happens when someone lies flat or stays immobile for…
Disuse osteoporosis is bone loss that happens when your skeleton isn't regularly loaded or moved enough, so it…
Growth hormone is a hormone, peaking during deep sleep, that stimulates bone-building cells called osteoblasts.
The maintenance phase is the stage after you've built up bone density, where the goal shifts to preserving those…
Sedentary behavior is spending most of your time sitting or moving at low intensity, which gives your bones little…
Sleep and bone health refers to how good sleep habits and enough quality sleep support your body's bone-maintaining…
Smoking harms bone by reducing blood flow to bone tissue and disrupting estrogen metabolism, making it a modifiable…
Stress management means using habits like movement, mindfulness, breathing, social connection, and time in nature to…
