Dryness may be related to normal aging or a disease like Sjogren's syndrome.
When mucus glands stop secretion, dryness occurs. But aging-related dryness is a little different from Sjogren's related dryness in mucus gland structure and function.
Aging related dryness is caused by mucus glands resting. There is no inflammation or tissue damage. But in Sjogren's, mucus glands may be dysfunctional due to inflammation and/or tissue damage caused by autoimmune reaction.
Mucinex can open up a resting mucus gland, but sea buckthorn oil may heal inflamed mucus glands.
Time required for having an effect may be different. The effect of sea buckthorn oil may be slow. You may need to take sea buckthorn oil daily for two weeks to see an effect. But Mucinex may show effect in just a few hours.
For duration of the effect, once you are on the Sea buckthorn oil pill, it may have a long-lasting effect on dryness relief. It also may also help prevent stroke and heart attack, and have other health effects.
But for Mucinex, its effect may go away after you stop using the product. But for healthy resting mucus glands, once they are weaken up, they may continue to be functional.
Thus, if you are a healthy woman without Sjogren's syndrome or another autoimmune disease like lupus, or rheumatoid arthritis, Mucinex may work better, but if your dryness is related to an autoimmune disease, sea buckthorn oil may work better.
Since each person's health condition is different, it would be a good idea to test each product and decide which one may work better.
If your dryness is severe, it may be a good idea to try both products for a combined healing effect.