Calcium
Research reviewed: Up until 03/2026
Calcium is a dietary supplement with 26 published peer-reviewed studies involving 3,281 participants, researched for Bone Health, Blood Pressure, Fracture Prevention and 4 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Bone Health
StrongBlood Pressure
ModerateFracture Prevention
WeakPremenstrual Syndrome (PMS)
ModerateColorectal Cancer Prevention
WeakAdolescent & Child Bone Development
ModerateWeight Management
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Bone Health
To assess the effects of calcium carbonate supplementation over 5 years on bone structure and clinical fracture incidence in elderly women
Study Type
Double-blind, placebo-controlled, randomised trial
Purpose
To assess the effects of calcium carbonate supplementation over 5 years on bone structure and clinical fracture incidence in elderly women
Dose
1,200 mg/day elemental calcium (as calcium carbonate) or placebo
Participants
1,460 elderly women aged ≥ 70 years
Duration
5 years
Results
Researchers observed that calcium supplementation significantly reduced the risk of all clinical fractures by 13% . Bone mineral density (an indicator of bone strength) at the hip was also significantly higher after 5 years in women taking calcium, with a difference of about 1–2%). In addition, cortical bone width at the tibia (the main lower leg bone; thicker bone means stronger structure) was significantly greater, suggesting calcium helped maintain bone strength and structure, reducing fracture risk over time.
To determine whether oral calcium supplementation produces a sustained reduction in bone loss in healthy postmenopausal women with relatively low dietary calcium intake
Study Type
Randomised, double-blind, placebo-controlled trial — extension of a 2-year RCT to 4 years
Purpose
To determine whether oral calcium supplementation produces a sustained reduction in bone loss in healthy postmenopausal women with relatively low dietary calcium intake
Dose
1 g elemental calcium per day (oral tablets) or placebo, with no change in usual diet
Participants
78 women who had completed an earlier 2-year double-blind trial; aged at least 3 years postmenopause at enrolment
Duration
4 years total (2-year extension of the original 2-year trial), with bone density measured every 6 months
Results
Researchers observed that total body bone mineral density (a measure of bone strength) showed a significant slowing of bone loss in the calcium group over the full 4-year period. Specifically, during years 2–4, bone loss was significantly reduced by 0.25% per year. However, there was no significant effect at specific sites like the lumbar spine (lower back bones) or proximal femur (upper thigh/hip area) in years 3–4, suggesting the benefit may vary depending on the part of the body.
To determine long-term effects of calcium supplementation on bone density and fracture prevention in postmenopausal women
Study Type
Randomized, double-blind, placebo-controlled trial
Purpose
To determine long-term effects of calcium supplementation on bone density and fracture prevention in postmenopausal women
Dose
1200 mg elemental calcium daily (as calcium citrate or carbonate)
Participants
168 healthy postmenopausal women aged 50-65 years
Duration
2-4 years
Results
Sustained calcium supplementation produced sustained reduction in bone mineral density loss. Women on calcium supplementation had fewer symptomatic fractures
How They Measured It
Bone mineral density (BMD), fracture incidence, biochemical markers
To assess calcium supplementation effects on bone loss and fracture risk in healthy older women
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To assess calcium supplementation effects on bone loss and fracture risk in healthy older women
Dose
1,200 mg/day elemental calcium
Participants
Healthy postmenopausal women aged 50-65 years
Duration
5 years
Results
Calcium supplementation significantly reduced bone loss and improved bone mineral density at the hip and other sites.
How They Measured It
Bone mineral density (BMD), clinical fracture incidence
To evaluate the long-term effects of calcium on bone loss in postmenopausal women
Study Type
Randomised, controlled trial
Purpose
To evaluate the long-term effects of calcium on bone loss in postmenopausal women
Dose
1,200 mg/day elemental calcium
Participants
168 healthy postmenopausal women aged 50-65 years
Duration
4 years
Results
Sustained calcium supplementation produced sustained reduction in bone mineral density loss. Fewer symptomatic fractures in calcium group.
How They Measured It
Bone mineral density (BMD)
Serum magnesium is linked with sperm concentration, motile sperm count and serum anti-Müllerian hormone in infertile men
Study Type
Randomised, double-blind, placebo-controlled
Purpose
Serum magnesium is linked with sperm concentration, motile sperm count and serum anti-Müllerian hormone in infertile men
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Effects of Greek Yogurt Supplementation and Exercise on Markers of Bone Turnover and Inflammation in Older Adult Exercisers: An 8-Week Pilot Intervention Trial
Study Type
Randomised, double-blind, placebo-controlled
Purpose
Effects of Greek Yogurt Supplementation and Exercise on Markers of Bone Turnover and Inflammation in Older Adult Exercisers: An 8-Week Pilot Intervention Trial
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Effects of Combined Exercise and Calcium/Vitamin D Supplementation on Bone Mineral Density in Postmenopausal Women: A Systematic Review and Meta-Analysis
Study Type
Systematic review and meta-analysis
Purpose
Effects of Combined Exercise and Calcium/Vitamin D Supplementation on Bone Mineral Density in Postmenopausal Women: A Systematic Review and Meta-Analysis
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Impact of high-dose vitamin D and calcium carbonate supplementation on bone density in adolescents living with HIV: a randomised, placebo-controlled trial
Study Type
Randomised, double-blind, placebo-controlled
Purpose
Impact of high-dose vitamin D and calcium carbonate supplementation on bone density in adolescents living with HIV: a randomised, placebo-controlled trial
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Effects of combined nutritional supplementation and exercise on proxy measures of muscle mass, strength, and function in older adults with sarcopenia: a 12-week multicentre RCT
Study Type
Randomised, double-blind, placebo-controlled
Purpose
Effects of combined nutritional supplementation and exercise on proxy measures of muscle mass, strength, and function in older adults with sarcopenia: a 12-week multicentre RCT
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems
Study Type
Systematic review and meta-analysis
Purpose
Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Blood Pressure
To determine whether oral calcium supplementation reduces blood pressure in patients with established essential hypertension
Study Type
Randomised, double-blind, placebo-controlled crossover trial
Purpose
To determine whether oral calcium supplementation reduces blood pressure in patients with established essential hypertension
Dose
1 g/day elemental calcium (oral supplement) or placebo
Participants
18 patients with uncomplicated essential hypertension (mild-to-moderate); no antihypertensive medication during the trial
Duration
15 weeks per treatment period
Results
Researchers observed that standing systolic blood pressure (SBP—the top number in a blood pressure reading, showing pressure when the heart pumps; high levels increase risk of heart disease) was significantly reduced by −8.6 mmHg with calcium supplementation compared to placebo. The effect was stronger in people who had higher urinary calcium excretion (a measure of how much calcium is lost in urine, reflecting how the body handles calcium), with a strong inverse relationship, meaning those losing more calcium in urine had the biggest blood pressure improvements. This suggests calcium may be especially helpful for a specific group of people with this underlying calcium imbalance.
To evaluate the effect of calcium supplementation on blood pressure reduction
Study Type
Meta-analysis of randomized clinical trials
Purpose
To evaluate the effect of calcium supplementation on blood pressure reduction
Dose
Calcium supplementation (various doses)
Participants
Meta-analysis of multiple RCTs (1231+ subjects)
Duration
Various study periods
Results
Calcium supplementation reduced systolic blood pressure by approximately -1.44 to -1.86 mmHg and diastolic blood pressure by -0.84 to -0.99 mmHg, with larger reductions in people with relatively low baseline calcium intake.
How They Measured It
Systolic and diastolic blood pressure change
To assess the influence of dietary and nondietary calcium supplementation on blood pressure
Study Type
Meta-analysis of randomized controlled trials
Purpose
To assess the influence of dietary and nondietary calcium supplementation on blood pressure
Dose
Calcium supplementation (various doses)
Participants
Meta-analysis of multiple RCTs
Duration
Various study durations
Results
Updated meta-analysis found calcium supplementation reduced systolic BP by -1.86 mmHg and diastolic BP by -0.99 mmHg with modest clinical significance.
How They Measured It
Blood pressure response
Fracture Prevention
To evaluate effectiveness and safety of treatments to prevent fractures in people with low bone mass or primary osteoporosis
Study Type
Systematic review and meta-analysis
Purpose
To evaluate effectiveness and safety of treatments to prevent fractures in people with low bone mass or primary osteoporosis
Dose
Calcium ± Vitamin D (various doses)
Participants
Meta-analysis of multiple RCTs
Duration
Various study durations
Results
Calcium supplementation, particularly when combined with Vitamin D, effective in reducing fracture risk in postmenopausal and older women.
How They Measured It
Fracture risk reduction, bone mineral density
Premenstrual Syndrome (PMS)
To evaluate the effect of calcium supplementation on premenstrual syndrome symptoms
Study Type
Double-blind, randomized controlled trial
Purpose
To evaluate the effect of calcium supplementation on premenstrual syndrome symptoms
Dose
500 mg elemental calcium daily
Participants
Women with documented premenstrual syndrome
Duration
Multiple menstrual cycles
Results
Calcium supplementation significantly reduced overall PMS symptoms across menstrual cycles. Three premenstrual factors (negative affect, water retention, and pain) and one menstrual factor (pain) were significantly alleviated by calcium. 73% of women reported fewer symptoms during the treatment phase on calcium.
How They Measured It
PMS symptom scores (negative affect, water retention, pain, fatigue, appetite, depression)
To examine the effects of calcium carbonate on premenstrual and menstrual symptoms
Study Type
Randomised, double-blind, placebo-controlled trial
Purpose
To examine the effects of calcium carbonate on premenstrual and menstrual symptoms
Dose
1,200 mg/day calcium carbonate
Participants
Women with moderate to severe PMS
Duration
3 menstrual cycles
Results
Calcium carbonate significantly reduced premenstrual and menstrual symptoms including mood changes, pain, and water retention compared to placebo.
How They Measured It
PMS symptom assessment
To evaluate calcium supplementation in women with premenstrual syndrome
Study Type
Randomized crossover trial
Purpose
To evaluate calcium supplementation in women with premenstrual syndrome
Dose
Calcium supplementation
Participants
Women with documented PMS
Duration
Multiple cycles
Results
Calcium supplementation showed beneficial effects in reducing PMS symptoms in a crossover design study.
How They Measured It
PMS severity scores
Colorectal Cancer Prevention
To evaluate the effect of calcium supplementation on prevention of colorectal adenomas (precancerous polyps)
Study Type
Systematic review and meta-analysis of randomized controlled trials
Purpose
To evaluate the effect of calcium supplementation on prevention of colorectal adenomas (precancerous polyps)
Dose
Calcium 1,200-2,000 mg/day
Participants
Meta-analysis of multiple RCTs in individuals with history of adenomas
Duration
3-5 years
Results
Calcium supplementation showed a modest protective effect on adenoma prevention (RR = 0.89, 95%CI: 0.82-0.96; high quality evidence). Number needed to treat was 20 to prevent one adenoma recurrence within 3-5 years.
How They Measured It
Adenoma recurrence, advanced adenoma risk
To evaluate the role of calcium supplementation in the chemoprevention of colorectal cancer
Study Type
Systematic review and meta-analysis
Purpose
To evaluate the role of calcium supplementation in the chemoprevention of colorectal cancer
Dose
Calcium supplementation (various doses)
Participants
Meta-analysis of observational and clinical studies
Duration
Various study periods
Results
Each 300 mg/day increase in total calcium intake was associated with approximately 8% reduced risk of colorectal cancer. Randomized trials showed more modest effects than observational studies.
How They Measured It
Colorectal cancer incidence, adenoma risk
Adolescent & Child Bone Development
To evaluate calcium supplementation and bone mineral accretion in adolescent girls
Study Type
Randomized controlled trial with 2-year follow-up
Purpose
To evaluate calcium supplementation and bone mineral accretion in adolescent girls
Dose
792 mg/day elemental calcium
Participants
96 adolescent girls aged 12 years with low calcium intakes
Duration
18 months intervention with 2-year follow-up
Results
Calcium supplementation enhanced bone mineral accretion and bone mineral density at most skeletal sites during intervention, with significantly lower bone resorption markers compared to placebo. However, gains were no longer evident 42 months after supplement withdrawal.
How They Measured It
Bone mineral content, bone mineral density, bone resorption markers
To assess bone mass and density response to calcium and vitamin D supplementation in preadolescent girls
Study Type
Randomized, double-blind, placebo-controlled trial
Purpose
To assess bone mass and density response to calcium and vitamin D supplementation in preadolescent girls
Dose
800 mg calcium carbonate + 400 IU vitamin D daily
Participants
Preadolescent girls aged 12 years
Duration
12 months
Results
Combined calcium and vitamin D supplementation significantly improved bone mineral density acquisition in preadolescent girls during critical bone development period.
How They Measured It
Bone mineral density (DXA), bone mineral content
To evaluate cumulative effects of calcium supplementation and physical activity on bone accretion in premenarchal children
Study Type
Double-blind, randomized, placebo-controlled trial
Purpose
To evaluate cumulative effects of calcium supplementation and physical activity on bone accretion in premenarchal children
Dose
Calcium supplementation
Participants
Premenarchal children
Duration
Multiple years
Results
The combination of calcium supplementation and physical activity had synergistic beneficial effects on bone mineral accretion in growing children.
How They Measured It
Bone mineral content, bone mineral density
Weight Management
To evaluate the effect of calcium supplementation on weight loss and fat loss in women
Study Type
Randomized, placebo-controlled trial
Purpose
To evaluate the effect of calcium supplementation on weight loss and fat loss in women
Dose
Elemental calcium supplementation
Participants
Women with overweight/obesity
Duration
25 weeks
Results
Calcium supplementation combined with dietary modification produced modest weight loss and fat loss compared to placebo.
How They Measured It
Body weight, fat mass, body composition
To evaluate effects of calcium supplementation on body weight and adiposity in overweight and obese adults
Study Type
Randomized, double-blind, placebo-controlled trial
Purpose
To evaluate effects of calcium supplementation on body weight and adiposity in overweight and obese adults
Dose
1,500 mg/day elemental calcium
Participants
Overweight and obese adults
Duration
2 years
Results
Calcium supplementation alone had no statistically or clinically significant effects on weight change in overweight and obese adults.
How They Measured It
Body weight, fat mass, BMI
To evaluate calcium plus vitamin D3 supplementation for fat loss in college students with low calcium intake
Study Type
Randomized controlled trial
Purpose
To evaluate calcium plus vitamin D3 supplementation for fat loss in college students with low calcium intake
Dose
Calcium plus vitamin D3 supplementation
Participants
Overweight and obese college students with very-low calcium consumption
Duration
12 weeks
Results
Calcium plus vitamin D3 supplementation facilitated fat loss in overweight and obese individuals with low baseline calcium intake, independent of energy restriction.
How They Measured It
Body weight, fat mass, BMI
Frequently Asked Questions
Common questions about Calcium research
There are currently 26 peer-reviewed studies on Calcium (Calcium), involving 3,281 total participants. Research covers Bone Health, Blood Pressure. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (19 human studies), and reported outcomes.
Calcium has been researched for: Bone Health, Blood Pressure. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 19 out of 26 studies are human trials. Human trials carry more weight in our evidence scoring system.
Similar Supplements
Other supplements researched for similar health goals
