Red Spinach Extract: Nitrate, Blood Flow and Training
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Red Spinach Extract: half-life, strengths and approval status

Amounts studied · Approval status · Half-life notes

What is red spinach extract?

Red spinach extract is made from the leaves of a red amaranth plant and is rich in nitrate, which the body can turn into nitric oxide.

Also known as: red spinach, amaranth extract, Amaranthus, RSE.

Amounts studied

Studies used single doses of 1 g (about 90 mg nitrate) or 2 g (Haun 2016, Subramanian 2016), and 2 g a day (about 180 mg nitrate) for 11 weeks (Townsend 2022). These are study protocols, not a recommendation.

Approval status and how it is used

The NIH Dietary Supplement Label Database lists products with red spinach extract, such as Fermented Beets with Red Spinach from Dr. Mercola as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.

What studies show: in 16 healthy adults, a single 2 g dose raised nitrate and nitrite in blood and saliva for at least 8 hours compared with placebo (Subramanian 2016). In 15 healthy adults, a 1 g dose raised blood nitrate and calf blood flow after a cuff test, but did not change blood pressure, heart rate or arm artery dilation (Haun 2016). In 16 college baseball players, 2 g a day through 11 weeks of offseason training did not improve strength, power, body composition or blood pressure more than placebo (Townsend 2022). All three studies were small.

Safety: the abstracts do not report side effects. The sources here do not describe drug interactions.

Red spinach extract half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

We could not find a single published half-life or time to peak for red spinach extract that applies to a supplement dose, so we do not list one. After a single 2 g dose, blood nitrate stayed above placebo for at least 8 hours (Subramanian 2016).

How to track red spinach extract in Dose Track

  1. Add red spinach extract as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each dose when you take it so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

Dietary Nitratenitrate, inorganic nitrate Beetroot Juice (Dietary Nitrate)beet juice, beetroot powder L-CitrullineL-citrulline, citrulline malate

Frequently asked questions

What is the half-life of red spinach extract?+
We could not find a single published half-life or time to peak for red spinach extract that applies to a supplement dose, so we do not list one. After a single 2 g dose, blood nitrate stayed above placebo for at least 8 hours (Subramanian 2016).
Does red spinach extract improve workouts?+
In the one training trial we found, 11 weeks of 2 g a day did not improve strength, power or body composition in college baseball players compared with placebo.
Can I track red spinach extract in Dose Track?+
Yes. Red spinach extract is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each dose next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Subramanian D, Gupta S. Pharmacokinetic study of amaranth extract in healthy humans: a randomized trial. Nutrition. 2016;32(7-8):748-753.
  2. Haun CT, et al. Differential vascular reactivity responses acutely following ingestion of a nitrate rich red spinach extract. Eur J Appl Physiol. 2016;116(11-12):2267-2279.
  3. Townsend JR, et al. Influence of dietary nitrate supplementation on physical performance and body composition following offseason training in Division I athletes. J Diet Suppl. 2022;19(4):534-549.
  4. NIH ODS Dietary Supplement Label Database. Fermented Beets with Red Spinach (Dr. Mercola), dietary supplement label, entered February 26, 2020; checked October 28, 2026.
  5. FDA. Questions and answers on dietary supplements.

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