Why is Yuth Spermidine in Inspired Nutraceuticals Endless Hydration RTD?

Inspired Nutraceuticals has been busy. One of the reasons they were named a brand to watch in 2024 in PricePlow’s 2023 Supplement Industry Awards was due to their launch of Endless, which took the name from an older intra-workout supplement they had launched in 2017, completely remaking it into a novel electrolyte hydration drink. We covered the new drink in our article, Inspired Nutraceuticals Endless RTD: For Endless Youth and Hydration.

Inspired Nutraceuticals Endless Hydration RTD: Why Spermidine

Why did Inspired Nutra add spermidine to Endless Hydration RTD? We look at the unique anti-aging and skin care spin to complement the hydration aspect

This delicious new formula is focused on one particular aspect of sports performance – hydration. Hydration is of vast importance, not only for athletic performance, but for basically every domain of human health.

While this topic is actually not as thoroughly researched as you might expect (it’s tough to patent water, salt, and potassium!), existing evidence indicates that optimizing hydration status is crucial for cognition, kidney function, and weight management,[1] as well as blood pressure and vascular function.[2]

The standard advice is to simply drink lots of water, which can work… up to a point. For one thing, the amount of water in your body doesn’t necessarily translate to cellular hydration, which is really what we’re after. Additionally, drinking lots of water doesn’t mean your body will retain it.

That’s why Inspired added some glycerol to Endless RTD — this does promote water retention and cellular hydration. And electrolyte balance is also important for cellular hydration.[3] Glycerol and electrolytes obviously make sense.

But why does Endless RTD contain Yüth spermidine inside?

That’s what we’re covering today. First, check out our Endless RTD price comparisons and sign up for our Inspired Nutraceuticals news notifications, then let’s get into it:

Inspired Nutraceuticals Endless RTD – Deals and Price Drop Alerts

Get Price Alerts

No spam, no scams.

Disclosure: PricePlow relies on pricing from stores with which we have a business relationship. We work hard to keep pricing current, but you may find a better offer.

Posts are sponsored in part by the retailers and/or brands listed on this page.

Hydration and Skin Health – The Link to Spermidine

Inspired Nutraceuticals Endless Teaser

The Inspired Nutraceuticals Endless RTD has an incredible sodium:potassium ratio, a bit of glycerol, and a novel anti-aging add-on in Yuth spermidine!

Inspired’s use of spermidine in Endless RTD represents an attempt to expand on the basic hydration drink concept. While spermidine doesn’t directly affect hydration like glycerol or electrolytes can, it does encourage some of the outcomes associated with proper hydration.

The big one is skin health. Dehydration dries out skin cells, giving skin a rough, scaly, or even flaky texture and appearance. These effects can be counteracted by increased water intake. For example, one study found that drinking more water improved epidermal hydration and elasticity in the same manner as a topical moisturizer.[4]

But besides the aesthetic concerns, chronic dehydration can also actually cause premature skin aging.[5] So what can we do to help reverse the damage caused by chronic dehydration?

That’s where Inspired Nutra brings in spermidine – taking Endless to the next level.

What is spermidine, and how can it help skin alongside hydration?

Spermidine is a polyamine,[6] meaning it consists of two or more different amino acids. Animal studies have found that spermidine can activate a process called autophagy, derived from a Greek word that literally means “self-eating”, but scientists usually prefer “self-renew”.[7]

During autophagy, your body’s cells dismantle damaged or dysfunctional cellular components and recycle them into new, healthy, functional ones. If a cell is damaged beyond repair, autophagy can even trigger apoptosis, a process in which that cell undergoes programmed self-destruction.[8] The damaged cell can then be replaced by a healthy one.

Spermidine Autophagy

Spermidine extends lifespans of yeast, flies, and
human immune cells while inhibiting oxidative stress in aging mice.[9]

Autophagy’s role in cellular rejuvenation is crucial for long-term cellular health and homeostasis. For one thing, autophagy is your body’s first line of defense against out-of-control cellular proliferation, which can lead to enormous health issues if allowed to proceed unchecked. And in general, since bodily youth is partly a function of cellular youth, autophagy is important for delaying the effects of aging as well.[8]

Spermidine Ingestion Mortality

Spermidine intake has been shown to be inversely related to all major causes of death.[12]

Polyamines play an important role in autophagy regulation, and are synthesized endogenously by the body. Unfortunately, as we get older, our body’s ability to do this declines, as does its rate of autophagy.[10] As a result, senescent cellular material builds up more and more as we age, a mechanism responsible for many of aging’s unwanted effects.[8,11]

If we want to help maintain autophagy as we get older, then supplemental polyamines like spermidine are a great potential strategy. Although longitudinal human studies are currently lacking, in vitro and in vivo animal studies have shown that spermidine can increase lifespan and healthspan of lower organisms like yeast, flies, worms, and even human immune cells.[9]

Autophagy and skin health/appearance

Unsurprisingly, there’s a close connection between autophagy and skin health.[13]

For example, one study found a close connection between decreased autophagy and hyperpigmentation, which can cause senile lentigo (liver spots) during photoaging (the aging of skin in response to sun exposure).[14] Cells in these skin spots were characterized by severe dehydration and skin barrier dysfunction.[14]

Spermidine Hair Growth: Fighting Hair Loss with Polyamines

Can spermidine supplementation support more hair growth and reduced hair loss? Research from the trifecta of human, in vitro, and animal research all indicate yes! (see article linked below)

Using in vitro experiments, the same study found that restoring autophagy significantly improved cellular hydration status and skin barrier integrity.[14]

By skin barrier, we are referring to the fact that one of skin’s most crucial functions is to keep pathogens, toxins, and other pathogenic substances out of the body. Seen this way, skin is really your body’s first line of immune defense. And unfortunately, when autophagy slows down, the skin barrier weakens.[15]

In other words, upregulating autophagy through spermidine supplementation can potentially improve not just skin appearance, but also skin’s immunological function.

But when it comes to improving appearance, autophagy doesn’t just help reduce liver spots. In fact, as one study title reads, “autophagy plays an essential role in ultraviolet radiation-driven skin photoaging,”[16] and loss of autophagy increases the damage caused to skin by sun exposure, and hence, the rate of skin aging.[16]

One especially interesting piece of evidence that autophagy manages skin photodamage is the fact that exposure to UV light triggers the upregulation of autophagy.[17,18] This direct connection between the two mechanisms suggests that autophagy’s role in skin health is evolutionarily conserved.

Autophagy and hair health

It’s industry convention to mention skin, hair and nails in the same breath, since these tissues depend on many of the same nutrients for optimal health and function.

While peer-reviewed evidence linking fluid intake to hair health is lacking, it seems reasonable to assume that if you’re interested in making your skin look luscious, you probably want the same for your hair. And fortunately, spermidine can help with that too![19-21]

Spermidine Stops Hair Loss in Mice

The reduction of hair loss in aged mice taking spermidine was so impressive that the researchers focused on this before discussing the other metabolic and organ health improvements![21]

We actually wrote an article about the connection between spermidine and hair growth – there’s a lot of really compelling research on this specific topic. If you want to read it, read Spermidine for Hair Growth: Fighting Hair Loss with Polyamines. We also have a full article on spermidine itself for even more info.

Other Skin-Supporting Ingredients in Endless RTD

Now that we’ve established how Yüth spermidine from Compound Solutions can help improve skin health and appearance, it’s worth mentioning that a couple other ingredients in Endless RTD can actually do the same.

  • Vitamin C (ascorbic acid) – 100 mg (110% DV)

    Although vitamin C is most famous as a systemic antioxidant and pro-immune supplement, it has some important effects on skin health as well.

    Inspired Nutraceuticals Endless RTD

    Looking for even more hydration before your workout? Inspired just dropped their new hydration drink!

    For one thing, skin health depends on collagen production, and vitamin C can potentially help with that. A 2018 meta-analysis of 10 peer-reviewed studies showed that vitamin C supplements can increase the body’s synthesis of collagen type I,[22,23] which is the predominant and most-studied collagen in mammals and other vertebrates.

    Skin cells in particular are absolutely dependent on ample vitamin C supply for collagen production.[24]

    Vitamin C’s status as an antioxidant is important for its role in skin health, too. Healthy skin cells contain large amounts of vitamin C, which protects those cells from the oxidative stress typical of UV-induced photodamage.[24] Intuitively we might expect topical vitamin C application to be the best strategy for this, but actually, recent studies have shown that increasing systemic vitamin C levels through oral supplementation is more effective.[24]

  • Biotin (as d-Biotin) – 30 mcg (100% DV)

    Inspired Nutra Endless RTD

    Biotin (vitamin B7) is one of the standard hair, skin, and nail ingredients, and it’s no wonder since biotin deficiency can cause big problems for all three tissues – problems that include dermatitis[25] and hair loss.[26,27]

    In one study, women with brittle nails took high-dose biotin, and about 50% of them experienced a significant reduction in the number of split ends.[28]

    While the dose used in that study was way bigger than the dose in Endless RTD – about 2.5 grams vs. 30 micrograms – in this case, the smaller dose is more physiologically appropriate. The goal here is to prevent deficiency, and it isn’t clear that biotin must be megadosed in order to have a clinical effect.

For a full write-up, see our main Inspired Nutraceuticals Endless Hydration RTD article. We haven’t even gotten into the 3:2 potassium:sodium ratio in this article — so you can read more about that here.

All Flavors Available

    Conclusion: More than just Endless Hydration

    Inspired Logo

    Since 2014, Inspired has been coming out with some of the most innovative products on the market to ‘fuel what inspires you’.

    Inspired Nutraceuticals’ Endless RTD is more than just a hydration formula – through the use of ingredients like spermidine, vitamin C, and biotin, this formula is designed to help optimize hydration-related health markers via multiple mechanisms beyond hydration itself.

    This is quite a novel product — and the taste is on point too (especially that Forbidden Fruit flavor). It’s even more respectable once you remember that it has a 3:2 potassium:sodium ratio, which does make things tougher to flavor. Inspired made it happen, and that’s why this is at the top of our Hydration stable right now.

    Inspired Nutraceuticals Endless RTD – Deals and Price Drop Alerts

    Get Price Alerts

    No spam, no scams.

    Disclosure: PricePlow relies on pricing from stores with which we have a business relationship. We work hard to keep pricing current, but you may find a better offer.

    Posts are sponsored in part by the retailers and/or brands listed on this page.

    About the Author: Mike Roberto

    Mike Roberto

    Mike Roberto is a research scientist and water sports athlete who founded PricePlow. He is an n=1 diet experimenter with extensive experience in supplementation and dietary modification, whose personal expertise stems from several experiments done on himself while sharing lab tests.

    Mike's goal is to bridge the gap between nutritional research scientists and non-academics who seek to better their health in a system that has catastrophically failed the public.

    No Comments | Posted in , | Tagged , , , , , .


    1. Liska, DeAnn et al. “Narrative Review of Hydration and Selected Health Outcomes in the General Population.” Nutrients vol. 11,1 70. 1 Jan. 2019, doi:10.3390/nu11010070 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356561/
    2. Watso, Joseph C, and William B Farquhar. “Hydration Status and Cardiovascular Function.” Nutrients vol. 11,8 1866. 11 Aug. 2019, doi:10.3390/nu11081866 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723555/
    3. James, Lewis J, and Susan M Shirreffs. “Effect of electrolyte addition to rehydration drinks consumed after severe fluid and energy restriction.” Journal of strength and conditioning research vol. 29,2 (2015): 521-7. doi:10.1519/JSC.0000000000000657; https://journals.lww.com/nsca-jscr/fulltext/2015/02000/effect_of_electrolyte_addition_to_rehydration.29.aspx
    4. Palma, Lídia et al. “Dietary water affects human skin hydration and biomechanics.” Clinical, cosmetic and investigational dermatology vol. 8 413-21. 3 Aug. 2015, doi:10.2147/CCID.S86822; https://www.dovepress.com/dietary-water-affects-human-skin-hydration-and-biomechanics-peer-reviewed-fulltext-article-CCID
    5. Cao, Changwei et al. “Diet and Skin Aging-From the Perspective of Food Nutrition.” Nutrients vol. 12,3 870. 24 Mar. 2020, doi:10.3390/nu12030870 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146365/
    6. Pegg, Anthony E. “Functions of Polyamines in Mammals.” Journal of Biological Chemistry, vol. 291, no. 29, 7 June 2016, pp. 14904–14912, 10.1074/jbc.r116.731661; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4946908/
    7. Xi, Hongyan, et al. “The Role of Interaction between Autophagy and Apoptosis in Tumorigenesis (Review).” Oncology Reports, vol. 48, no. 6, 11 Oct. 2022, https://www.spandidos-publications.com/10.3892/or.2022.8423
    8. Barbosa, María Carolina et al. “Hallmarks of Aging: An Autophagic Perspective.” Frontiers in endocrinology vol. 9 790. 9 Jan. 2019, doi:10.3389/fendo.2018.00790 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6333684/
    9. Eisenberg, Tobias, et al. “Induction of Autophagy by Spermidine Promotes Longevity.” Nature Cell Biology, vol. 11, no. 11, 1 Nov. 2009, pp. 1305–1314, 10.1038/ncb1975; https://pubmed.ncbi.nlm.nih.gov/19801973/
    10. Nishimura, Kazuhiro, et al. “Decrease in Polyamines with Aging and Their Ingestion from Food and Drink.” Journal of Biochemistry, vol. 139, no. 1, 1 Jan. 2006, pp. 81–90, 10.1093/jb/mvj003; https://pubmed.ncbi.nlm.nih.gov/16428322/
    11. Aman, Yahyah et al. “Autophagy in healthy aging and disease.” Nature aging vol. 1,8 (2021): 634-650. doi:10.1038/s43587-021-00098-4 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8659158/
    12. Kiechl, Stefan, et al. “Higher Spermidine Intake Is Linked to Lower Mortality: A Prospective Population-Based Study.” The American Journal of Clinical Nutrition, vol. 108, no. 2, 28 June 2018, pp. 371–380, 10.1093/ajcn/nqy102; https://academic.oup.com/ajcn/article/108/2/371/5046172
    13. Eckhart, Leopold et al. “Autophagic Control of Skin Aging.” Frontiers in cell and developmental biology vol. 7 143. 30 Jul. 2019, doi:10.3389/fcell.2019.00143 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682604/
    14. Murase, Daiki et al. “Autophagy Declines with Premature Skin Aging resulting in Dynamic Alterations in Skin Pigmentation and Epidermal Differentiation.” International journal of molecular sciences vol. 21,16 5708. 9 Aug. 2020, doi:10.3390/ijms21165708 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7460956/
    15. Sil, Payel et al. “More Than Skin Deep: Autophagy Is Vital for Skin Barrier Function.” Frontiers in immunology vol. 9 1376. 25 Jun. 2018, doi:10.3389/fimmu.2018.01376 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6026682/
    16. Ma, Jingwen et al. “Autophagy plays an essential role in ultraviolet radiation-driven skin photoaging.” Frontiers in pharmacology vol. 13 864331. 6 Oct. 2022, doi:10.3389/fphar.2022.864331 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9582953/
    17. Gu, Yanpei et al. “Biomarkers, oxidative stress and autophagy in skin aging.” Ageing research reviews vol. 59 (2020): 101036. doi:10.1016/j.arr.2020.101036 https://www.sciencedirect.com/science/article/abs/pii/S156816371930474X
    18. Zhao, Zhen et al. “A dual role for UVRAG in maintaining chromosomal stability independent of autophagy.” Developmental cell vol. 22,5 (2012): 1001-16. doi:10.1016/j.devcel.2011.12.027 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356442/
    19. Ramot, Yuval et al. “Spermidine promotes human hair growth and is a novel modulator of human epithelial stem cell functions.” PloS one vol. 6,7 (2011): e22564. doi:10.1371/journal.pone.0022564; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144892/
    20. Rinaldi, Fabio et al. “A spermidine-based nutritional supplement prolongs the anagen phase of hair follicles in humans: a randomized, placebo-controlled, double-blind study.” Dermatology practical & conceptual vol. 7,4 17-21. 31 Oct. 2017, doi:10.5826/dpc.0704a05; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718121/
    21. Wirth, Alexander, et al. “Novel Aspects of Age-Protection by Spermidine Supplementation Are Associated with Preserved Telomere Length.” GeroScience, 31 Jan. 2021, doi:10.1007/s11357-020-00310-0; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110654/
    22. Shaw, Gregory et al; “Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis.”; The American journal of clinical nutrition; vol. 105,1; 2017; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5183725/
    23. DePhillipo, Nicholas N., et al. “Efficacy of Vitamin c Supplementation on Collagen Synthesis and Oxidative Stress after Musculoskeletal Injuries: A Systematic Review.” Orthopaedic Journal of Sports Medicine, vol. 6, no. 10, Oct. 2018, p. 232596711880454, 10.1177/2325967118804544; https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC6204628/
    24. Pullar, Juliet M., et al. “The Roles of Vitamin c in Skin Health.” Nutrients, vol. 9, no. 8, 12 Aug. 2017, p. 866; doi:10.3390/nu9080866; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579659/
    25. Mock, D. M. “Skin Manifestations of Biotin Deficiency.” Seminars in Dermatology, vol. 10, no. 4, 1 Dec. 1991, pp. 296–302; https://pubmed.ncbi.nlm.nih.gov/1764357/
    26. Lanska, Douglas J. “The Discovery of Niacin, Biotin, and Pantothenic Acid.” Annals of Nutrition and Metabolism, vol. 61, no. 3, 2012, pp. 246–253, 10.1159/000343115; https://pubmed.ncbi.nlm.nih.gov/23183297/
    27. Zempleni, Janos, et al. “Biotin and Biotinidase Deficiency.” Expert Review of Endocrinology & Metabolism, vol. 3, no. 6, 1 Nov. 2008, pp. 715–724, 10.1586/17446651.3.6.715; https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2726758/
    28. Colombo, V. E., et al. “Treatment of Brittle Fingernails and Onychoschizia with Biotin: Scanning Electron Microscopy.” Journal of the American Academy of Dermatology, vol. 23, no. 6 Pt 1, 1 Dec. 1990, pp. 1127–1132, 10.1016/0190-9622(90)70345-i; https://pubmed.ncbi.nlm.nih.gov/2273113/

    Comments and Discussion (Powered by the PricePlow Forum)