Witch Hazel for Vaginal Tightening and Rejuvenation
Witch Hazel is a shrub or plant that rich in Tannin content like Oak Gall had. Tannins is an important agent that can make tissues in the vaginal walls tight due to astringent properties.(ref)
This phytochemical content of Tannins can be obtained by extracting the bark and leaves of the shrub. For more detail about Tannins, you may see in Oak gall page.
In addition to tannin content, extract of this shrub also rich in natural Phenols.
Phenols is small molecule that can make other chemical contents carried by them easily diffuse across cell membrane and reach intracellular site for certain actions.
This means, the tannins content will be easily absorbed in the tissues and work based on their abilities - constricting the vaginal tissues.

The ability of Phenols have been studied by some researches. For recent analysis, it just demonstrated by German researcher and archived in the Analytical and Bioanalytical Chemistri, 2011 Aug;401(2):677-88.
For the effect of Tannin for astringent properties, it has long been known since the scientists investigated the effect of Oak gall that initially used by Asian women post vaginal delivery to restore the strengthen of their genital organ and vaginal health as well. Eventually they found certain agent called Tannin that play a role in constricting the tissues.
That's why in the literature, Tannin means Oak tree. However, as witch hazel also has lot of phenols, the astringent properties of this plant may become faster and powerful.

In addition to natural phenol effect, as extract of Witch hazel also rich in phytoestrogen, it will be easily absorbed to the vaginal tissues and stimulate collagen production and expression on the tissues, making the vaginal walls become youthful, firmness and elastic faster for long-term effect.
Estrogen also beneficial to maintain the strengthen the vaginal muscles.
As the results, extract of Witch hazel doesn't only tighten the vaginal walls, but also rejuvenate the vaginal walls and muscles.

Similarly to Oak gall, Witch hazel also have antioxidant, anti-inflammatory, and antibacterial. Interestingly, the antimicrobial and anti-inflammatory of this plant have another effects that can protect the cells from toxicities. This effect found when the researcher investigated its action again colon cancer cells. (ref)
There is no more strongest botanical sources in rejuvenating and tightening properties of the vaginal tissues and muscle other than Witch Hazel and Oak gall.
The good news, there is certain products that provide them ALL, V-Tight Gel, making it becomes the best natural treatment for vaginal rejuvenation and tightening in single application with a cream/gel-based product. See this page for how it works.