Reviewed by Dr Ilma Imtiaz

Quick answer: Calcium, vitamin D, magnesium, and bioactive collagen peptides each support bone health in different ways. Calcium and vitamin D help maintain normal bone mineralization, magnesium contributes to normal bone metabolism, and Fortibone®, a specific bioactive collagen peptide, has been clinically studied for supporting healthy bone remodeling and bone mineral density in postmenopausal women at a dose of 5 g/day.

Why Bone Health Is About More Than Calcium

Bone is a living tissue made up of two main components: a mineral phase, consisting primarily of calcium phosphate crystals, and a collagen-rich protein matrix that provides strength and flexibility [1]. Throughout life, bone is continuously broken down and rebuilt through a process known as bone remodeling. After menopause, this balance shifts toward greater bone breakdown than formation, leading to lower bone mineral density (BMD) and an increased risk of fractures over time. Because healthy bones rely on both a well-mineralized structure and a strong collagen framework, nutrients such as calcium, vitamin D, magnesium, and bioactive collagen peptides each support different aspects of bone biology. Understanding these different roles helps explain why they do not all produce the same outcomes in clinical studies.

What Calcium Actually Does 

Calcium is the most abundant mineral in bone and plays an essential role in maintaining normal bone mineralization. When dietary calcium intake is consistently too low, the body draws calcium from the skeleton to help maintain stable blood calcium levels, which over time can contribute to bone loss [2].

Observational studies have generally associated adequate calcium intake, typically around 1,000–1,200 mg per day from food and supplements combined, with higher BMD and a lower risk of fractures, particularly in people with low baseline calcium intake [3]. However, evidence from randomized controlled trials paints a more nuanced picture. While some meta-analyses have reported that calcium combined with vitamin D is associated with modest reductions in fracture risk, particularly in older adults or those with inadequate calcium intake, others have found little or no benefit in generally healthy, community-dwelling adults [3-5].

Overall, the evidence suggests that calcium supplementation is most useful for maintaining normal bone mineralization and helping slow age-related bone loss, rather than substantially increasing bone density. In many studies, changes in BMD have been relatively modest, often around 1–2% over several years, particularly in individuals who already meet their calcium requirements.

How About Vitamin D?

Vitamin D plays a different role. Rather than becoming part of bone itself, vitamin D helps the body absorb calcium efficiently and supports normal bone mineralization [6]. Correcting vitamin D deficiency is therefore an important component of maintaining healthy bones.

Clinical research shows that vitamin D supplementation alone has relatively small effects on bone mineral density in adults who already have adequate vitamin D status [6]. When combined with calcium, however, vitamin D may provide modest improvements in bone health and reduce fracture risk in some higher-risk populations [3-6]. In practice, vitamin D is best viewed as a nutrient that helps calcium do its job, rather than a stand-alone strategy for improving bone density.

Where Does Magnesium Fit?

Magnesium receives less attention than calcium and vitamin D, but it also contributes to normal bone metabolism. It acts as a cofactor for many enzymes involved in bone remodeling and plays a role in vitamin D activation and calcium regulation. Magnesium glycinate is often selected because it is generally well tolerated and suitable for everyday use. However, while maintaining adequate magnesium intake is important for overall bone health, the current evidence for increasing bone mineral density with magnesium supplementation alone remains limited. At present, magnesium is best viewed as supporting overall bone metabolism rather than as a primary strategy for improving bone density.

Where Do Bioactive Collagen Peptides Fit?

While calcium provides minerals and vitamin D supports calcium absorption, collagen represents another important part of bone biology. Approximately 90–95% of the organic matrix of bone consists of type I collagen, which forms the scaffold onto which minerals are deposited. This collagen framework contributes to both bone strength and flexibility.

Bioactive collagen peptides are short, specific peptide fragments produced through controlled hydrolysis of collagen. Researchers have become interested in whether these peptides may help support healthy bone remodeling by interacting with bone-forming cells and supporting the collagen-rich matrix of bone.

Importantly, not all collagen supplements are the same. The strongest clinical evidence relates to Fortibone®, a specific bioactive collagen peptide that has been investigated in human studies of bone health [7-10].

What the Fortibone® Clinical Studies Show

As discussed earlier, calcium and vitamin D provide the nutritional foundation for healthy bones, but clinical studies generally suggest they are more effective at maintaining normal bone mineralization and helping slow bone loss than substantially increasing bone mineral density. Researchers have therefore investigated whether adding specific bioactive collagen peptides may provide complementary support by supporting the collagen-rich framework of bone.

Several randomized clinical studies have evaluated Fortibone® in postmenopausal women with osteopenia or reduced bone mineral density [7-10]. In a 12-month randomized, double-blind, placebo-controlled trial involving 131 women, participants received either 5 g/day of Fortibone® or a placebo [8]. Compared with placebo, the Fortibone® group showed significant improvements in bone mineral density at both the lumbar spine and femoral neck, together with favorable changes in bone turnover markers consistent with healthy bone remodeling. Researchers later followed a subgroup of participants for up to four years and reported that continued use of 5 g/day of Fortibone® was associated with sustained improvements in bone mineral density compared with the expected age-related decline typically observed after menopause [7].

Additional randomized studies have also evaluated Fortibone® in combination with calcium and vitamin D [9-10]. Compared with calcium and vitamin D alone, women receiving the combination showed greater improvements in bone turnover markers, lumbar spine bone mineral density, and measures of bone microarchitecture. These findings suggest that Fortibone® may complement the nutritional foundation provided by calcium and vitamin D, rather than replace it.

Taken together, the available clinical evidence suggests that Fortibone® may help support healthy bone remodeling and bone mineral density in postmenopausal women with low bone mass. Importantly, these findings are specific to Fortibone® and should not automatically be generalized to other collagen supplements.

Comparing the Current Evidence

Although these nutrients are often discussed together, they contribute to bone health in different ways.

They Work Together, Not Against Each Other

One of the most important findings is that these nutrients are not competing strategies.

• Calcium provides the mineral building blocks of bone.
• Vitamin D helps the body absorb and use calcium efficiently.
• Magnesium supports normal bone metabolism and contributes to vitamin D function.
• Bioactive collagen peptides support the collagen-rich framework that gives bone its structure.

Rather than asking which nutrient is "best," the evidence suggests they play complementary roles. The published studies investigating Fortibone® were conducted alongside normal nutritional support, and additional research combining collagen peptides with calcium and vitamin D has reported favorable effects on bone turnover and bone density [2-5].

Take-Home Message

Supporting healthy bones involves more than a single nutrient. Calcium, vitamin D, magnesium, and collagen each contribute to different aspects of bone biology, making them complementary rather than competing strategies.

Current evidence suggests calcium and vitamin D remain the nutritional foundation for healthy bones, while magnesium supports normal bone metabolism. Specific bioactive collagen peptides such as Fortibone® represent an additional, ingredient-specific approach that has been investigated for supporting healthy bone remodeling and bone mineral density in postmenopausal women with low bone mass.

Importantly, the published evidence relates to Fortibone® at 5 g/day, rather than collagen supplements in general.

FAQs

What is the best calcium supplement for osteoporosis?

The best calcium supplement depends on your dietary intake, health status, and individual needs. Most experts recommend meeting calcium needs through food where possible and using supplements when dietary intake is insufficient.

Is calcium and vitamin D enough for osteoporosis?

Calcium and vitamin D are important for maintaining healthy bones, but they are only part of a comprehensive bone health strategy. Nutrition, exercise, healthy lifestyle habits, and medical care all play important roles.

Should I stop taking calcium if I start taking Fortibone®?

No. Calcium and bioactive collagen peptides support different aspects of bone health. The published studies investigating Fortibone® were conducted alongside adequate nutritional care, suggesting these approaches are complementary rather than interchangeable.

Are bioactive collagen peptides natural supplements for osteoporosis?

Bioactive collagen peptides are dietary supplements that have been investigated for supporting bone health. They are not approved to treat, cure, or prevent osteoporosis.

Is magnesium glycinate good for osteoporosis?

Magnesium contributes to normal bone metabolism and maintaining adequate magnesium intake is important for overall bone health. However, the current evidence for improving bone mineral density with magnesium supplementation alone is limited compared with calcium, vitamin D, and specific bioactive collagen peptides.

Can I take calcium, vitamin D, and collagen peptides together?

Yes. Because these nutrients support different aspects of bone biology, they are commonly viewed as complementary rather than competing. If you have osteoporosis or another bone condition, speak with your healthcare provider before starting any new supplement regimen.

References

1. Lin X, Patil S, Gao YG, Qian A. The bone extracellular matrix in bone formation and regeneration. Front Pharmacol. 2020;11:757. https://doi.org/10.3389/fphar.2020.00757

2. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific opinion on dietary reference values for calcium. EFSA J. 2015;13(5):4101. https://doi.org/10.2903/j.efsa.2015.4101 

3. Weaver CM, Alexander DD, Boushey CJ, et al. Calcium plus vitamin D supplementation and risk of fractures: an updated meta-analysis from the National Osteoporosis Foundation. Osteoporos Int. 2016;27(1):367-376. https://doi.org/10.1007/s00198-015-3386-5

4. Albani E, Petrou P. A systematic review and meta-analysis of vitamin D and calcium in preventing osteoporotic fractures. Clin Rheumatol. 2020;39(12):3571-3579. https://doi.org/10.1007/s10067-020-05122-3 

5. Massé O, Mercurio CM, Dupuis S, et al. Calcium, vitamin D, or combined supplementation to prevent fractures and falls: systematic review and meta-analysis. BMJ. 2026;393:e088050. https://doi.org/10.1136/bmj-2025-088050 

6. Yao P, Bennett D, Mafham M, et al. Vitamin D and calcium for the prevention of fracture: a systematic review and meta-analysis. JAMA Netw Open. 2019;2(12):e1917789. https://doi.org/10.1001/jamanetworkopen.2019.17789 

7. Zdzieblik D, Oesser S, König D. Specific bioactive collagen peptides in osteopenia and osteoporosis: long-term observation in postmenopausal women. J Bone Metab. 2021;28(3):207-213. https://doi.org/10.11005/jbm.2021.28.3.207 

8. König D, Oesser S, Scharla S, Zdzieblik D, Gollhofer A. Specific collagen peptides improve bone mineral density and bone markers in postmenopausal women: a randomized controlled study. Nutrients. 2018;10(1):97. https://doi.org/10.3390/nu10010097 

9. Lampropoulou-Adamidou K, Karlafti E, Argyrou C, et al. Effect of calcium and vitamin D supplementation with and without collagen peptides on volumetric and areal bone mineral density, bone geometry and bone turnover in postmenopausal women with osteopenia. J Clin Densitom. 2022;25(3):357-372. https://doi.org/10.1016/j.jocd.2021.11.011 

10. Argyrou C, Karlafti E, Lampropoulou-Adamidou K, et al. Effect of calcium and vitamin D supplementation with and without collagen peptides on bone turnover in postmenopausal women with osteopenia. J Musculoskelet Neuronal Interact. 2020;20(1):12-17. https://pubmed.ncbi.nlm.nih.gov/32131366/

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.