Vitamin D3 vs Vitamin D2 for Perimenopause: Which Form Should You Take?
Vitamin D3 and D2 both raise vitamin D levels, but they are not identical. Find out which form is better for bone health and wellbeing during perimenopause.
Why Vitamin D Matters in Perimenopause
Vitamin D plays a central role in calcium absorption and bone mineralisation. During perimenopause, falling oestrogen accelerates bone loss, making adequate vitamin D intake more important than ever. Most women in the UK and northern latitudes are deficient or insufficient in vitamin D, particularly during autumn and winter. Beyond bones, vitamin D receptors are found throughout the body including in immune cells, muscle tissue, and the brain, so low levels can contribute to fatigue, low mood, muscle weakness, and increased susceptibility to illness. Many women in perimenopause discover their vitamin D is low after a blood test, and face the question of which supplement to take.
What Is Vitamin D3
Vitamin D3, also called cholecalciferol, is the form of vitamin D that human skin produces in response to sunlight. It is also found in oily fish, egg yolks, and liver, and in most widely available vitamin D supplements. D3 is generally considered the more effective form for raising and maintaining blood levels of 25-hydroxyvitamin D, which is the form measured in blood tests. Studies comparing the two forms consistently show D3 raises serum levels more efficiently and sustains them for longer, partly because it converts to the active form more readily in the liver and kidneys.
What Is Vitamin D2
Vitamin D2, also called ergocalciferol, is derived from plant sources including yeast and fungi exposed to UV light. It is the form traditionally used in food fortification and was historically the most common form in prescription supplements. D2 does raise vitamin D levels, but research suggests it is less potent gram for gram than D3, and levels may decline more quickly between doses. D2 is often chosen by those following a vegan or vegetarian diet because most D3 supplements are derived from lanolin, a substance from sheep's wool, though vegan D3 from lichen is now widely available.
Comparing the Two Forms
For raising blood vitamin D levels efficiently, D3 has the edge in most research. A review published in the American Journal of Clinical Nutrition found D3 was approximately 87 percent more potent than D2 in raising serum 25-hydroxyvitamin D. For everyday supplementation, most menopause specialists and dietitians recommend D3 as the first choice. That said, D2 is not ineffective. If someone has been prescribed D2 or prefers it for dietary reasons and takes it consistently at an adequate dose, it can still meaningfully improve vitamin D status. The key is consistent supplementation at the right level rather than sporadic high doses.
Dosage and Timing
Most adults benefit from 1,000 to 2,000 IU (25 to 50 micrograms) of vitamin D daily as a maintenance dose, though those who are deficient may need higher doses under medical supervision. Vitamin D is fat-soluble, so taking it with a meal containing some fat improves absorption. Supplements combining D3 with vitamin K2 are popular because K2 helps direct calcium to bones rather than soft tissues, which may offer additional bone protection. If you have had a blood test showing deficiency, discuss the appropriate repletion dose with your GP or pharmacist rather than self-prescribing high doses long-term.
Practical Takeaway
For most women in perimenopause, vitamin D3 is the better-supported choice for maintaining bone health and overall wellbeing. Vegan women can now access lichen-derived D3, so dietary preference does not have to mean choosing the less effective form. Regardless of form, taking it consistently matters more than which exact type you choose. If you are already monitoring symptoms like fatigue, low mood, or joint pain, a regular supplement routine combined with symptom tracking can help you notice whether things improve over time. PeriPlan allows you to log how you feel day to day so you can spot shifts in energy and wellbeing.
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