Vitamin C, also known as ascorbic acid, is a water-soluble nutrient found in some foods. In the body, it acts as an antioxidant, helping to protect cells from the damage caused by free radicals. Free radicals are compounds formed when our bodies convert the food we eat into energy. People are also exposed to free radicals in the environment from cigarette smoke, air pollution, and ultraviolet light from the sun.

https://ods.od.nih.gov/factsheets/VitaminC-Consumer/

Vitamin D is a nutrient you need for good health. It helps your body absorb calcium, one of the main building blocks for strong bones. Together with calcium, vitamin D helps protect you from developing osteoporosis, a disease that thins and weakens the bones and makes them more likely to break. Your body needs vitamin D for other functions too. Your muscles need it to move, and your nerves need it to carry messages between your brain and your body. Your immune system needs vitamin D to fight off invading bacteria and viruses.

https://ods.od.nih.gov/factsheets/VitaminD-Consumer/

Zinc is found in cells throughout the body. It helps the immune system fight off invading bacteria and viruses. The body also needs zinc to make proteins and DNA, the genetic material in all cells. During pregnancy, infancy, and childhood, the body needs zinc to grow and develop properly. Zinc also helps wounds heal and is important for proper senses of taste and smell.

https://ods.od.nih.gov/factsheets/Zinc-Consumer/

Quercetin is a plant pigment (flavonoid). It is found in many plants and foods, such as red wine, onions, green tea, apples, berries, Ginkgo biloba, St. John's wort, American elder, and others. Buckwheat tea has a large amount of quercetin. Quercetin may antioxidant and anti-inflammatory support.

WebMD, https://www.webmd.com/vitamins/ai/ingredientmono-294/quercetin

Boswellia, or Indian frankincense, is a resin herbal extract from the boswellia tree, which natural medicine practices have used for centuries. Its anti-inflammatory effects mean that it may help with inflammatory conditions, such as rheumatoid arthritis, inflammatory bowel disease, and asthma.

https://www.medicalnewstoday.com/articles/326599#_noHeaderPrefixedContent

Urtica dioica has traditionally been used in the control of cardiovascular disorders especially hypertension. The leaf extract of Urtica dioica has been reported to improve glucose homeostasis in vivo. Nettle root could prevent some of the effects of prostatic hyperplasia.

https://pubmed.ncbi.nlm.nih.gov/31163183/

Cysteine is a semi-essential amino acid. It's considered semi-essential because your body can produce it from other amino acids, namely methionine and serine. It becomes essential only when the dietary intake of methionine and serine is low.

Cysteine is found in most high-protein foods, such as chicken, turkey, yogurt, cheese, eggs, sunflower seeds and legumes.

N-acetyl cysteine (NAC) is a supplement form of cysteine.

Consuming adequate cysteine and NAC is important for a variety of health reasons - including replenishing the most powerful antioxidant in your body, glutathione. These amino acids also help with chronic respiratory conditions, fertility and brain health.

https://www.healthline.com/nutrition/nac-benefits

Lemons, limes, grapefruits, and oranges are high in phytonutrients, such as carotenoids, flavonoids, and polyphenols. These nutrients are types of antioxidants and give the fruits their bright colors and strong scents. They can also help protect your body and prevent many health issues.

https://www.webmd.com/diet/health-benefits-citrus-fruits#1

Bromelain is a protein-digesting enzyme mixture derived from the stem, fruit, and juice of the pineapple plant. It has a centuries-long history of being used to treat medical ailments, primarily throughout Central and South America.

https://www.healthline.com/health/bromelain

There is evidence that grape seed extract is beneficial for a number of cardiovascular conditions. Grape seed extract may help with a type of poor circulation (chronic venous insufficiency) and high cholesterol. Grape seed extract also reduces swelling caused by injury and helps with eye disease related to diabetes.

https://www.webmd.com/diet/grape-seed-extract

Betaine works by preventing the build-up of an amino acid called homocysteine. This amino acid can harm blood vessels and contribute to heart disease, stroke, or circulation problems. Betaine is used to reduce homocysteine levels in people with a genetic condition called homocystinuria, in which the amino acid builds up in the body. Betaine is not a cure for homocysteinuria.

https://www.drugs.com/mtm/betaine.html