What are the recommendations for taking vitamins and collagen supplements?

Vitamin and Collagen Supplementation Recommendations

Vitamins for General Health

For healthy adults without documented nutritional deficiencies, routine vitamin supplementation is not recommended for preventing cardiovascular disease or cancer, as the evidence is insufficient to determine benefits and harms. 1, 2

Key Guideline Recommendations

• The USPSTF concludes there is insufficient evidence to recommend for or against multivitamins, vitamin A, C, or E supplements for disease prevention in healthy adults. 1

• Beta-carotene supplementation should be avoided, particularly in smokers and those with asbestos exposure, as it increases lung cancer incidence and all-cause mortality. 1, 3

• Vitamin E supplementation provides no net benefit for cardiovascular disease or cancer prevention and should not be routinely recommended. 1

When Vitamin Supplementation IS Appropriate

• Women planning pregnancy or capable of becoming pregnant should take folic acid supplementation to prevent neural tube defects. 1, 2

• Patients on metformin require periodic vitamin B12 monitoring and supplementation if deficient. 2

• Documented nutritional deficiencies warrant targeted replacement therapy rather than general multivitamins. 2

• Patients on certain medications (e.g., folic acid for those taking methotrexate) may require specific vitamin supplementation. 1

• Older adults at risk for falls may benefit from vitamin D supplementation (typically combined with calcium). 1

Important Safety Considerations

• If patients choose to take vitamins despite insufficient evidence, counsel them to adhere to Dietary Reference Intake dosages, as vitamins A and D can be harmful at high doses. 1, 2

• Emphasize that supplements do not replace healthy dietary patterns rich in fruits, vegetables, whole grains, and legumes, which have more consistent evidence for health benefits. 1, 2

• Vitamin B6 intake above 2.03 mg/day may reduce hip fracture risk in older women, though optimal supplementation protocols require further study. 1

Clinical Approach

• Focus clinical efforts on dietary counseling rather than supplement prescription, as whole food sources provide superior and more consistent health benefits. 1, 2

• For patients with adequate dietary intake, standard multivitamins containing approximately 100% of Daily Value are reasonable if patients insist, though not evidence-based for disease prevention. 3

• Prioritize dietary sources of B vitamins (meat, fish, dairy, fortified foods) over supplements when possible. 3

Collagen Supplementation

Current evidence does not support collagen supplementation for preventing or treating skin aging, as high-quality, industry-independent studies show no significant benefits. 4

Critical Evidence Analysis

• A 2025 meta-analysis of 23 randomized controlled trials revealed that when studies funded by pharmaceutical companies were excluded, collagen supplements showed no effect on skin hydration, elasticity, or wrinkles. 4

• High-quality studies demonstrated no significant improvement in any skin parameter, while only low-quality studies showed benefits. 4

• Industry-funded studies consistently showed positive results, suggesting significant publication bias and conflicts of interest in the collagen supplement literature. 4

What Earlier Research Suggested (But Higher Quality Evidence Refutes)

• Earlier, predominantly industry-funded trials (2018-2019) suggested improvements in skin elasticity, hydration, and wrinkle reduction with doses of 2.5-10g daily for 8-24 weeks. 5, 6

• A 2024 study found benefits with 5g hydrolysed collagen plus 80mg vitamin C for dermis density and skin texture, but not for elasticity or hydration. 7

Clinical Bottom Line on Collagen

• There is no clinical evidence to support prescribing or recommending collagen supplements for skin aging or general health based on the most recent, highest-quality systematic review. 4

• The apparent benefits in earlier studies were driven by industry funding and methodological limitations rather than true biological effects. 4

• Vitamin C does play a legitimate role in collagen synthesis at the cellular level, but this does not translate to clinically meaningful benefits from oral collagen supplementation. 7, 8

Common Pitfalls to Avoid

• Do not recommend collagen based on industry-sponsored studies or patient testimonials, as these are unreliable sources of evidence. 4

• Patients may confuse the biological role of collagen in skin with evidence for oral supplementation efficacy—these are separate issues. 8

• Collagen supplements are generally safe with no reported serious adverse events, but lack of harm does not justify recommendation without proven benefit. 5