Conclusion: Raw milk consumption was not associated with cancer (two studies) or lactose intolerance (one study). Overall, these findings should be interpreted with caution given the poor quality of reported methodology in many of the included studies.
PubMed 22054181 ↗Vitamin a
People mainly take Vitamin a for skin & hair, focus, mood. Based on 65 first-hand reports and 533 meta-analyses & systematic reviews in the medical literature. Ranked #702 of 1,974 overall.
Of reports that state an outcome, 43% are positive.
What Vitamin a does, according to users
Of the people who reported each effect, the share who said it got better.
5 more with fewer than 3 reports
What the research says
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
3+ meta-analyses or systematic reviews and 10+ randomized controlled trials in humans. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: The included studies support the potential role of antioxidant vitamins in the management of endometriosis. Supplementation with antioxidant vitamins effectively reduced the severity of dysmenorrhea, improved dyspareunia and pelvic pain, and enhanced quality of life in these patients. Therefore, antioxidant vitamin therapy could be considered as an alternative treatment method, either alone or in combination with other approaches, for endometriosis-related pain.
PubMed 37644533 ↗Conclusion: This update identified no new eligible studies and the conclusions remain the same. VAS is associated with a clinically meaningful reduction in morbidity and mortality in children. Further placebo-controlled trials of VAS in children between six months and five years of age would not change the conclusions of this review, although studies that compare different doses and delivery mechanisms are needed. In populations with documented VAD, it would be unethical to conduct placebo-controlled trials.
PubMed 35294044 ↗Conclusion: The data showed that high-dose intake of vitamins A (OR=0.63, 95%CI [0.53, 0.76]) and B (OR=0.71, 95%CI [0.64, 0.80]) but not vitamins C (OR=0.69, 95%CI [0.48, 1.01]), D (OR=0.90, 95%CI [0.45, 1.83]), or E (OR=0.91, 95%CI [0.71, 1.16]) was associated with a low prevalence of glaucoma. The results of this study demonstrated that high-dose intake of vitamins A and B, but not vitamins C, D, or E, was associated with a low prevalence of glaucoma.
PubMed 35120728 ↗Dosage people report
As stated by users — not a recommendation. Follow the label or your doctor.
Reported side effects
How often each side effect came up across all reports.
What users say
Verbatim quotes, shortened only — each links to the original discussion.
“more zinc, more vitamin D but not too much A or D or it will increase your risk”
“I've added L-Carnitate, Vitamin A, C and E to the mix.”
“I don't absorb vitamin a well so I take vitamin a”
“Flooding the body with excessive Vitamin A or E has been discovered to be moderately carcinogenic...2000-4000 IU Vitamin A supplement (as beta-carotene, not the common palmitic acid which promotes cancer metastasis).”
“When specific antioxidants, such as Vitamin A/E, are exposed to an environment with a profusion of free radicals they will become oxidized and create peroxy radicals”
Top discussions (5)
- My Biohacking Protocol!!! 1-Year Difference: Tackling Acne, Redness, and Inflammation ↗
- Vitamin D3 is amazing ↗
- Scientists create supercharged vitamin K that helps the brain heal itself ↗
- Guide to vitamins and minerals: What to look for in multivitamins ↗
- Vitamin A & Vitamin D deficiencies more common in ADHD children; Co-deficiency of both vitamins associated with worse symptoms (2020) [n = 188] ↗
Other options for skin & hair
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 2, 2026. How we rate