Retinol

What it is

• Vitamin A is a group of fat-soluble compounds, mainly retinol and retinyl esters.
• Preformed vitamin A, which includes retinol, is found in foods from animals such as dairy, eggs, fish, and organ meats.
• Vitamin A is stored in the liver.

Sources: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗ · MedlinePlus (NIH): Vitamin A: MedlinePlus Medical Encyclopedia ↗

How it's thought to work

The body turns retinol into retinal and retinoic acid, the two main active forms of vitamin A. Vitamin A is needed for the light-sensitive protein in the eye that responds to light.

Source: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗

What people use it for

Vitamin A is involved in immune function, cell communication, growth, and reproduction. Standard care for cystic fibrosis includes lifelong vitamin A treatment.

Source: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗

What the research has found so far

A review of trials found vitamin A supplements reduced new cases of measles by 50% in children at high risk of deficiency. Studies do not show that vitamin A supplements help prevent cancer.

Sources: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗ · NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Consumer ↗

On Retinol and aging, PubMed lists 30 trials in people, 11 studies that watched people over time, 10 animal and lab studies. See the counts and searches

Side effects and risks

• Acute vitamin A toxicity can cause severe headache, blurred vision, nausea, dizziness, aching muscles, and coordination problems.
• In severe cases, pressure in the fluid around the brain can rise, leading to drowsiness, coma, and even death.
• Regular high doses can cause dry skin, painful muscles and joints, fatigue, depression, and abnormal liver test results.
• Intakes of preformed vitamin A above the upper limit can cause birth defects.

Source: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗

Who should be careful, and drug interactions

• Experts advise women who are or might be pregnant, and those who are breastfeeding, not to take high-dose vitamin A supplements.
• Babies and children can become sick from smaller doses of vitamin A.
• Swallowing products with vitamin A, such as skin cream with retinol, can cause vitamin A poisoning.
• Retinoid medicines taken with vitamin A supplements can raise the risk of too much vitamin A.
• Acitretin and bexarotene taken with a vitamin A supplement could cause dangerously high blood levels of vitamin A.
• The weight-loss drug orlistat can lower how much vitamin A the body absorbs.
• In smokers, former smokers, and asbestos-exposed workers, large doses of beta-carotene with retinyl palmitate raised lung cancer risk in trials.

Sources: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗ · MedlinePlus (NIH): Vitamin A: MedlinePlus Medical Encyclopedia ↗ · NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Consumer ↗

Amounts used in studies

What studies or labels describe, not a recommendation.

• The recommended daily amount of vitamin A is 900 mcg RAE for adult men and 700 mcg RAE for adult women.
• The upper limit for preformed vitamin A is 3,000 mcg a day for adults 19 and older.
• Supplements most often come as retinyl acetate or retinyl palmitate.
• Studies in children used doses of 15,000 to 60,000 mcg RAE, as a single dose or every 4 to 6 months.
• The CARET trial used 25,000 IU of retinyl palmitate plus 30 mg beta-carotene daily.

Sources: NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Consumer ↗ · MedlinePlus (NIH): Vitamin A: MedlinePlus Medical Encyclopedia ↗ · NIH Office of Dietary Supplements: Vitamin A and Carotenoids - Health Professional Fact Sheet ↗

Roughly what it costs

The 3 products we list that contain Retinol cost from $8.10 to $16.70, as read from the makers' pages. See the products

Questions to ask your doctor

• Is Retinol a sensible option for me, given my health and the medicines I take?
• Could Retinol interact with any medicine or supplement I already take?
• What side effects should I watch for, and when should I stop or call you?
• Would Retinol be used for its approved purpose, or off-label for aging?
• How would we tell whether it is helping, and when should we review it?